canon rumors FORUM

Rumors => EOS Bodies => Topic started by: MichaelTheMaven on December 06, 2012, 03:31:26 AM

Title: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 03:31:26 AM
I did some more tests today with the Canon 6D, and one question I was most interested in was the low light ability of the Canon 6D's central focusing point.

The summary is this:

Between 0 --> -3EV, the Nikon D600 is about 10-15% faster than all of the Canons.
Between 0 --> -7EV, the Canon 6D is almost twice as fast as the 5Dii, ~20% faster than the 5Diii, and the Nikon D600 couldn't achieve any focus at all in extreme low light without it's AF illuminator.

(Note: Here "0" EV was an even exposure at 1/60, 2.8 ISO 400).

For those of you interested in the methodology and actual testing, as well as the specific results, you will want to check out my blog article on the test http://www.michaelthemaven.com/?postID=2577&canon-6d-vs-5diii-vs-5dii-vs-nikon-d600-low-light-focus-speed-comparison (http://www.michaelthemaven.com/?postID=2577&canon-6d-vs-5diii-vs-5dii-vs-nikon-d600-low-light-focus-speed-comparison).

I also tested the top center, and far right center focus points.

- While the Canon 6D's other focusing points are not nearly as impressive as the other focusing points on the 5Diii and Nikon D600, the 6D's center point is in fact very, very good in low light.

- The Nikon D600 and 5Dii's Central focus points felt much quicker, and snappy. The 5Dii, actually did very, very well in 0-> -3EV range. The 5Diii's & 6D's feel like there is a 2 step process to the focusing.

- The more I play around with the 6D, the more pleasantly surprised I am with it. (When I initially heard the specs I was seriously underwhelmed).

While I certainly wish there were more cross type focus points on the 6D, I think that with the low light focusing and relatively low ISO noise, the Canon 6D is going to be a very solid performer in low light situations.

M
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: davidbellissima on December 06, 2012, 04:52:45 AM
Very interesting test Michael. I own all three versions sof the 5D and I am frustrated by the very slow focus lock time, in very low light, of the 5D3. It can take a second or longer. It does seem like it is a two step process: get 95% there is maybe 30-40% of the time and the image through the viewfinder seems to be in focus, but then there is another 60-70% of the time taken on what must be some sort of focus refinement algorithm. Of course the total focus locking time varies with the lens being used, but it is still a pain. Imagine wedding first dances where the subjects are moving and the camera is taking an age to lock focus.

Anyway, maybe when I get rid on my 5D MK1&2 I will buy a 6D as the low light performance looks very good, if not better than the Mk3 and since I mainly use the centre focus point, that will do for me. That is, as long as the focusing on the 5D is as consitent and repaatible as on the Mk3. The Mk3 focusing accuracy and repeatibility is not the best...
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: ScottyP on December 06, 2012, 06:41:30 AM
Thanks Michael.  Very interesting indeed. A lot of folks wanted to see exactly that.  I wonder if you would be able to confirm/quantify the issue of 5d3 + 600ex speed lite AF assist = even worse lag?  (and comparing 6d on same speedlite AF too)  No one else is going to, and yet a lot of people are very interested in that! 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: zim on December 06, 2012, 07:51:51 AM
I thought the 6D autofocus in -3EV conditions was a one stop improvement over the 5d Mark III and a two stop improvement over the 5D Mark II? I don't know about the Nikon.
I don't really get testing beyond the rated limit, maybe I missunderstand further explaination of the -7EV thing would be much appreciated. I also seem to recall a video from DigitalRev (in the boxing ring) where the 5D3 excelled against the D600 no where near -3EV?
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: ScottyP on December 06, 2012, 08:08:04 AM
I don't really get testing beyond the rated limit, maybe I missunderstand further explaination of the -7EV thing would be much appreciated. I also seem to recall a video from DigitalRev (in the boxing ring) where the 5D3 excelled against the D600 no where near -3EV?

How can you not understand the interest in testing beyond the rated limit?  The light around you won't stay to the rated limit of your camera, right?   :)
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 08:15:48 AM
(Note: Here "0" EV was an even exposure at 1/60, 2.8 ISO 400).

You're adding a lot of confusion here by arbitrarily defining your own zero.  It's like saying you're going to start counting everything from the number 4, so if there are of 2 of something on a table, you're telling everyone there are 6.  Makes no sense.

0 EV has a real, absolute definition - an exposure of 1 s, f/1.0, ISO 100.

Technically, your "0" EV is actually EV = 5.  That means your -7 EV is really -2 EV (and in fact, the 6D is spec'd to AF at -3 EV, but of course, that may not equate to real world numbers).

It would help avoid confusion if you restate your numbers according to the real definition of EV = 0, otherwise many people will read that you're testing at "EV = -7" and think you're spewing complete bullsh cow manure.

Sorry, but the fact that you don't seem to understand some of the basics, like the fundamental definition of the basis for the specification you are testing, makes me question what you're doing.  I definitely appreciate individual testing (and especially the fact that you did post your definition, so the error could be spotted), but post/blogs like this contribute to the vast and growing pool of bad and/or unreliable information out there. 

How can you not understand the interest in testing beyond the rated limit?  The light around you won't stay to the rated limit of your camera, right?   :)

See...this is my point.  He's not testing beyond the rated limit of the 6D, he hasn't even tested it as low as the rated limit.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: prjkt on December 06, 2012, 08:19:26 AM
as a side note, in terms of AF assist with a 600EX, there was no noticeable difference in time between focus acquisition with the flash on (AF assist on) or switched off while shooting social shots in a nightclub for me
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: RS2021 on December 06, 2012, 08:37:40 AM
Ugh... Hope tests like this don't sway people. I wouldn't even know where to start with the holes and misinformation here. 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: wellfedCanuck on December 06, 2012, 08:44:28 AM
Ugh... Hope tests like this don't sway people. I wouldn't even know where to start with the holes and misinformation here.
I don't have the technical expertise to argue one way or the other- but if you're going to  make statements like that here then you owe the forum something to substantiate your assertion.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: DavidB on December 06, 2012, 08:57:00 AM
Thanks for the test results Michael.  I'm curious though if you did any tests comparing the expansion points on the 5d3 vs the 6d?  In my experience having 4 pt expansion greatly increases the speed of AF in low light on the 5d3. 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: skitron on December 06, 2012, 09:37:24 AM
Ugh... Hope tests like this don't sway people. I wouldn't even know where to start with the holes and misinformation here.

Given the point was to do a relative comparison and not an absolute measurement, I don't see much of a problem. Especially when he cited his definition of 'EV'. As neuro pointed out, it might add to the confusion a bit but it doesn't really invalidate anything.

That said, I'd be interested to delve in a bit deeper and test it's low light performance with respect to the ability to track and lock a moving subject relative the others. For me this will be the determining factor whether I send mine back for something else. Mine is showing up tomorrow, so I'll test and post...and I promise not to couch the results in terms of EV whether used correctly or otherwise...  :)
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 10:15:13 AM
Given the point was to do a relative comparison and not an absolute measurement, I don't see much of a problem. Especially when he cited his definition of 'EV'. As neuro pointed out, it might add to the confusion a bit but it doesn't really invalidate anything.

No, but now that I've looked at the methodology, there are other holes to be poked in the 'analysis'.  He's testing targets illuminated to different light levels, yes, but they seem to be different targets shot from different angles, therefore they may not be comparable for the same camera (and shooting an orthogonally-shaped target from an angle isn't the best way to test AF performance). 

The better way to have done this test would be to have pointed the cameras straight at the same target, and vary the light levels only.  I'd have set the illumination at 2 EV, then stepped down the illumination to -4 EV in 1-stop increments using ND filters on the lens.

Having said that, a generic conclusion that the 6D center point AF performs very well in low light is quite reasonable.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: 3kramd5 on December 06, 2012, 10:28:10 AM

0 EV has a real, absolute definition - an exposure of 1 s, f/1.0, ISO 100.

Then EV is amusingly useless since there are varying definitions of ISO 100.

I always thought exposure value was independent of sensitivity (i.e. merely a function of f number and exposure time). f/1 for 1 second happens to be EV 0, but EV 0 isn't defined as such.

Perhaps I'm mistaken.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 10:42:05 AM
Then EV is amusingly useless since there are varying definitions of ISO 100.

LOL...now that's amusing.  "ISO 100" is defined unequivocally by ISO 12232:2006 as published by the International Standards Organization (which is why we call it ISO). 

But you're point is valid.  In actuality, when set to ISO 100 the cameras in question are really at a sensitivity of ISO 73 - 80 based on the actual standard.  That's one of the things that DxOMark measures.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: 3kramd5 on December 06, 2012, 10:50:50 AM
Then EV is amusingly useless since there are varying definitions of ISO 100.

LOL...now that's amusing.  "ISO 100" is defined unequivocally by ISO 12232:2006 as published by the International Standards Organization (which is why we call it ISO). 

But you're point is valid.  In actuality, when set to ISO 100 the cameras in question are really at a sensitivity of ISO 73 - 80 based on the actual standard.  That's one of the things that DxOMark measures.

I don't have access to the standard, but per wiki:

"The ISO standard ISO 12232:2006[55] gives digital still camera manufacturers a choice of five different techniques for determining the exposure index rating at each sensitivity setting provided by a particular camera model. Three of the techniques in ISO 12232:2006 are carried over from the 1998 version of the standard, while two new techniques allowing for measurement of JPEG output files are introduced from CIPA DC-004.[56] Depending on the technique selected, the exposure index rating can depend on the sensor sensitivity, the sensor noise, and the appearance of the resulting image. The standard specifies the measurement of light sensitivity of the entire digital camera system and not of individual components such as digital sensors, although Kodak has reported[57] using a variation to characterize the sensitivity of two of their sensors in 2001."

So while maybe sensitivity has a specific definition, the affect of sensitivity on the result has myriad possible results, hence different cameras recording different luminance levels with equivalent exposure settings.

Also from wiki, EV=log2(Fnumber/ExposureTime).

In any case, it has no bearing on this discussion.

Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 10:57:29 AM
I don't have access to the standard...

In any case, it has no bearing on this discussion.

I do, but you're right.  However, we're talking about small (one stop or in most cases, much less) differences.  My point is that even though it's a relative measurement, labeling the test results as "-7 EV" is pretty darn misleading in light of the specified performance of the cameras being tested.  The difference between -2 EV and -7 EV is a 32-fold difference in light intensity.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: spinworkxroy on December 06, 2012, 11:18:41 AM
Isn't the 6D rated at -3ev while the 5d3 is rated at -2ev?
So in theory…the 6D should perform better in low light than the 5D3..so why are we surprised?

In good light however, it's a different story. I love my 5D3 in daylight but come night time…the focusing speed is a real downer..especially for a camera that has such good ISO capabilities…
Having ISO powers is useless when you can get a focus…i shot a few events at night with it and i constantly miss shots because it fails to focus.
Even with a flash, it wont focus fast enough..in fact with the IR on the flash, it became even slower..
I seriously hope, as do many others i read, that Canon does release some "fix" to make it focus faster in low light…
It's marketed as an event camera but without focusing, you can't shoot any event.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: 3kramd5 on December 06, 2012, 11:25:14 AM
I don't have access to the standard...

In any case, it has no bearing on this discussion.

I do, but you're right.  However, we're talking about small (one stop or in most cases, much less) differences.  My point is that even though it's a relative measurement, labeling the test results as "-7 EV" is pretty darn misleading in light of the specified performance of the cameras being tested.  The difference between -2 EV and -7 EV is a 32-fold difference in light intensity.

In fact, he actually tested something close to EV9 (log2(2.8^2*60)=8.88

It's only 7 if you include ISO (log2(2.8^2*60/4)

I get your point, I just often get hung up on little details I find interesting.
[/hijack]
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Marsu42 on December 06, 2012, 11:35:48 AM
0 EV has a real, absolute definition - an exposure of 1 s, f/1.0, ISO 100.
I always thought exposure value was independent of sensitivity (i.e. merely a function of f number and exposure time). f/1 for 1 second happens to be EV 0, but EV 0 isn't defined as such.

I think technically he wasn't wrong since EV is something to be defined, but it surely is confusing -  that's why af capability in low light should be measured in *lv* which incorporates iso 100 yadayadayada: http://www.kenrockwell.com/tech/ev.htm (http://www.kenrockwell.com/tech/ev.htm)

Quote
LV 0 LV Zero is defined as the light level that requires a 1 second exposure at f/1 with ISO/ASA100 speed film.

Btw, I asked sometime ago but got no answer - I don't understand why the af capability in low light seems to be independent of the lens used (i.e. open aperture), the metering range does - from the 6d specs:

Quote
Metering Range: EV 1-20 (at 73°F/23°C with EF50mm f/1.8 II lens, ISO 100)
AF Working Range: Center AF Point: EV -3 to 18 (at 73°F/23°C, ISO 100)
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Canon-F1 on December 06, 2012, 11:38:36 AM

(Note: Here "0" EV was an even exposure at 1/60, 2.8 ISO 400).

i stopped reading there.

sorry but this shows that you did not understand the whole principle... and that gives me not much confidence in your testing.   ::)

by the way... "best intentions" are often not the best way.

http://atlantablackstar.com/2012/08/27/good-deed-gone-bad-art-restoration-horribly-botche/ (http://atlantablackstar.com/2012/08/27/good-deed-gone-bad-art-restoration-horribly-botche/)

if you do it.. make sure you do it right.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Mt Spokane Photography on December 06, 2012, 11:44:59 AM
The test might be useful as a comparison between models, but there is no measured or controlled light level or color temperature. There is no reason to believe that different camera models respond the same to different color temperatures, so a standard temperature removes any arguement about that.  Measurements at various color temperatures might be interesting for comparison sake.
As to time to focus, its not clear as to how that was measured, I did not notice the methodology.  I have found the best way to get to focus is to merely press the shutter button all the way down while the camera is in one shot mode.  The camera will take the shot when focus is achieved.  Some cameras seem to delay turning on the AF light, but the camera is actually focused earlier.  A sensitive mike connected to a oscilloscope can record the shutter button press, and the shutter opening so you get a precise measurement, for example.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: helpful on December 06, 2012, 12:46:16 PM
Exposure value (EV) is not an amount of light and it also has nothing to do with ISO. It is simply a definition for relating camera settings which are equivalent to each other in terms of how much light they would let in, if there was the same amount of light available.

Setting your camera to f/1.0 and 1 second exposure is still called an EV of 0 even in complete darkness or in bright sunlight. Setting your camera to f/1.4 and 2 seconds exposure is still EV 0.

By telling someone that you are obtaining proper exposure by an EV of 0 and a certain ISO value, then and only then does the actual darkness or brightness of the scene come into play. In that case, changing the ISO will change the EV needed to obtain proper exposure for the same scene. And vice versa, changing the brightness of the scene will also change the EV needed to obtain proper exposure for the same ISO.

So you might ask why then does Canon present on their 6D product page a meaningless specification about sensitivity at -3 EV? EV doesn't mean luminance, but they are acting like it does.

The answer is that it is well-established practice among photographers to express luminance in terms of their camera settings using the EV terminology, by assuming that ISO 100 is used and that a nominally "correct" exposure is being obtained by the camera settings indicated by the specified EV. Since photographers probably communicate best when talking in terms of their camera settings, EV makes for an easy way to understand the level of available brightness for a photographer when this common practice is used.

Anytime exposure value is used to speak of the amount of available light, the assumption is that a CORRECT exposure will be obtained from that EV of aperture/shutter speed AND a sensor sensitivity of ISO 100.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: ishdakuteb on December 06, 2012, 12:57:35 PM
Quote
You're adding a lot of confusion here by arbitrarily defining your own zero.  It's like saying you're going to start counting everything from the number 4, so if there are of 2 of something on a table, you're telling everyone there are 6.  Makes no sense.

0 EV has a real, absolute definition - an exposure of 1 s, f/1.0, ISO 100.

Technically, your "0" EV is actually EV = 5.  That means your -7 EV is really -2 EV (and in fact, the 6D is spec'd to AF at -3 EV, but of course, that may not equate to real world numbers).

It would help avoid confusion if you restate your numbers according to the real definition of EV = 0, otherwise many people will read that you're testing at "EV = -7" and think you're spewing complete bullsh cow manure.

Sorry, but the fact that you don't seem to understand some of the basics, like the fundamental definition of the basis for the specification you are testing, makes me question what you're doing.  I definitely appreciate individual testing (and especially the fact that you did post your definition, so the error could be spotted), but post/blogs like this contribute to the vast and growing pool of bad and/or unreliable information out there. 

neuro, i have question on this part:  base to my conversion of everything back to iso 100, it shows that
- 1/60 f2.8 iso 400 (0)          will be equivalent to       1/15  f2.8 iso 100  which is     EV 7
- 1/60 f2.8 iso 102,400 (-7)  will be equalivant to       2       f1.0 iso 100  which is     EV -1

is there something wrong with my conversion?  however, taking a look into his images, i guess that he was talking about zone system instead of exposure value, but there is no such -7 zone system, and i am scratching my head over here :P
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: dlleno on December 06, 2012, 01:28:15 PM
...The answer is that it is well-established practice among photographers to express luminance in terms of their camera settings using the EV terminology, by assuming that ISO 100 is used and that a nominally "correct" exposure is being obtained by the camera settings indicated by the specified EV. Since photographers probably communicate best when talking in terms of their camera settings, EV makes for an easy way to understand the level of available brightness for a photographer when this common practice is used.

Anytime exposure value is used to speak of the amount of available light, the assumption is that a CORRECT exposure will be obtained from that EV of aperture/shutter speed AND a sensor sensitivity of ISO 100.

+1 helpful nice summary.  now can we get back to discussing the 6D's AF performance in terms that make sense and communicate the right story?  Lets use the term "EV 0" as it is nearly universally understood in terms of evaluating important camera capabilities. 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 02:02:06 PM
Ive always been surprised to meet highly intelligent individuals who are completely unable to process the most basic of information, simply because they are too smart to understand the heart of the matter.

Something to think about.

Love ya guys!

MM
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Chuck Alaimo on December 06, 2012, 02:20:18 PM
I thought the 6D autofocus in -3EV conditions was a one stop improvement over the 5d Mark III and a two stop improvement over the 5D Mark II? I don't know about the Nikon.
I don't really get testing beyond the rated limit, maybe I missunderstand further explaination of the -7EV thing would be much appreciated. I also seem to recall a video from DigitalRev (in the boxing ring) where the 5D3 excelled against the D600 no where near -3EV?

I watched that vid ---- it was testing the servo tracking of the 3 though, this is one shot focus mode
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 02:23:18 PM
I'm always surprised when people put forth results and a conclusion, and then are surprised when others critically evaluate the methods used to generate those results, and weigh the quality of the methods when evaluating the reliability of the results and the strength of the conclusions. 

Something else to think about.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Chuck Alaimo on December 06, 2012, 02:29:01 PM
grrrrr..... Ok, I'll say it, I don't really care about the methodology! What I care about is how well this camera's AF performs in a variety of situations. The definition of EV matters less to me than the results!  which in this case seem pretty good.  I'd like to see more of this!!!
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 02:39:47 PM
I'm always surprised when people put forth results and a conclusion, and then are surprised when others critically evaluate the methods used to generate those results, and weigh the quality of the methods when evaluating the reliability of the results and the strength of the conclusions. 

Something else to think about.

I welcome and appreciate criticism, but how does the discussion of semantics in this test somehow mean that the 6D doesn't focus well in low light?

Some people appreciated the amount of time & energy it took to do this. Some don't. But I do know this:

That center focus square on the 6D is very, very good in low light. Ill grab it before the others for low light situations.

If you cannot walk away from this post/discussion with that very basic, heart of the matter idea, than nothing I can say will matter to you.

No hard feelings either.

Thanks!

MM
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Chosenbydestiny on December 06, 2012, 02:41:38 PM
I'm always surprised when people put forth results and a conclusion, and then are surprised when others critically evaluate the methods used to generate those results, and weigh the quality of the methods when evaluating the reliability of the results and the strength of the conclusions. 

Something else to think about.

Makes me think about DXOMark tests
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: dlleno on December 06, 2012, 02:48:57 PM
back on topic --

Isn't the 6D rated at -3ev while the 5d3 is rated at -2ev?

the single AF point in the center is rated at -3EV sensitivity, yes.  However, per Canon product support the other 10 AF points are -1EV sensitive.  so -- the stationary "focus, then frame" approach with only the center AF point should yield a not-surprising one-stop advantage in very low light compared to the 5D3.  Note for interests sake that -3EV is four stops less light than requried for the exposure meter itself to perform up to its rated specifications!  so you can focus, but you  might want to get to know how the metering system behaves under those same conditions. 

Someone correct if wrong, but Canon also confirmed to me that all 61 AF points of the 5D3, on the other hand, are sensitive to -2EV.

Don't forget that EV sensitivity is not the only measure of success for the AF system.  for example, Roger over at lensrentals put these puppies to the test and discovered a wider variability in AF accuracy (std dev = 28 I believe) for the 6D compared to the more consistent 5D3 at std dev = 17.   thats a considerable difference. 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Helevitia on December 06, 2012, 03:04:11 PM
Thanks for the results.  I'm considering upgrading from a 7D.  How does the 7D compare in these tests?  Does anybody know?  I'm sure there have been similar tests done between 7D and 5D2/3?
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: rafaelsynths on December 06, 2012, 03:10:33 PM
I'm thinking of renting the canon 6D myself . Can anyone help me on my other post it has 3 replies and all of them are from me :(
I need some pro tips on whether to rent a 6D or 5D
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Marsu42 on December 06, 2012, 03:24:55 PM
Thanks for the results.  I'm considering upgrading from a 7D.  How does the 7D compare in these tests?  Does anybody know?

The af is supposed to work from -0,5lv ... my 60d from 0lv, so not much of a difference, and the af slows down considerably and I have to use af assist frequently. So the -3lv from the 6d (or -2lv from the 5d3 for that matter) should make a very, very large difference in speed and low light capability.

Note for interests sake that -3EV is four stops less light than requried for the exposure meter itself to perform up to its rated specifications!  so you can focus, but you  might want to get to know how the metering system behaves under those same conditions. 

Interesting point, I wondered about that, too and would like to see some reviews on that, but afaik it only matters for available light w/o en e-ttl flash.

for example, Roger over at lensrentals put these puppies to the test and discovered a wider variability in AF accuracy (std dev = 28 I believe) for the 6D compared to the more consistent 5D3 at std dev = 17.   thats a considerable difference. 

... but only if you use a large aperture lens and shoot with a thin dof, for other shots a little variation doesn't matter - 60d and esp. 7d are much less precise than the 6d.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: dlleno on December 06, 2012, 03:25:25 PM
Thanks for the results.  I'm considering upgrading from a 7D.  How does the 7D compare in these tests?  Does anybody know?  I'm sure there have been similar tests done between 7D and 5D2/3?

yes, the 7D fared among  the worst of all the cameras he tested.  FYI pardon my asssumption of background here, but for those unfamiliar, high standard devition is bad.  7D was 41, 5D3 was 17. 

http://www.imaging-resource.com/news/2012/08/01/autofocus-reality-part-3b-canon-cameras (http://www.imaging-resource.com/news/2012/08/01/autofocus-reality-part-3b-canon-cameras)


and Marsu42 yes good reality check. 

Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Chosenbydestiny on December 06, 2012, 03:46:41 PM
Thanks for the results.  I'm considering upgrading from a 7D.  How does the 7D compare in these tests?  Does anybody know?  I'm sure there have been similar tests done between 7D and 5D2/3?

yes, the 7D fared among  the worst of all the cameras he tested.  FYI pardon my asssumption of background here, but for those unfamiliar, high standard devition is bad.  7D was 41, 5D3 was 17. 

http://www.imaging-resource.com/news/2012/08/01/autofocus-reality-part-3b-canon-cameras (http://www.imaging-resource.com/news/2012/08/01/autofocus-reality-part-3b-canon-cameras)


and Marsu42 yes good reality check.

Could it be they had a bad copy of the 7D for testing? I've always remembered my old 7D focusing a bit better than my 60D.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Dylan777 on December 06, 2012, 03:52:16 PM
I'm always surprised when people put forth results and a conclusion, and then are surprised when others critically evaluate the methods used to generate those results, and weigh the quality of the methods when evaluating the reliability of the results and the strength of the conclusions. 

Something else to think about.

I welcome and appreciate criticism, but how does the discussion of semantics in this test somehow mean that the 6D doesn't focus well in low light?

Some people appreciated the amount of time & energy it took to do this. Some don't. But I do know this:

That center focus square on the 6D is very, very good in low light. Ill grab it before the others for low light situations.

If you cannot walk away from this post/discussion with that very basic, heart of the matter idea, than nothing I can say will matter to you.

No hard feelings either.

Thanks!

MM

Michael,
I'm not an expert in testing.

I did have a chance to play with 6D outside parking lot, behind business building, around 7PM westcoast. It was quite dark and the light sources were street lights. I compared to my 5D III and I didn't see the advantage of 6D has to offer in term of -3EV AF center point. Maybe it wasn't dark enough?  I shot with my 24-70 f2.8 II lens at f2.8. The outer points were bit slower though.

Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Marsu42 on December 06, 2012, 04:03:34 PM
Could it be they had a bad copy of the 7D for testing? I've always remembered my old 7D focusing a bit better than my 60D.

I guess you didn't do any (semi-)scientific tests? I don't have a 7d, but I've read many times that the af on the 7d is the least precise, and the lensrentals test confirms it - though by a margin you may not notice in day-to-day shooting because unfortunately the 60d is rather unprecise, too, and of course the lens also matters.

I compared to my 5D III and I didn't see the advantage of 6D has to offer in term of -3EV AF center point. Maybe it wasn't dark enough?  I shot with my 24-70 f2.8 II lens at f2.8. The outer points were bit slower though.

The good news for 6d buyers is that obviously you didn't see any disadvantage, too - and yes, I guess it wasn't dark enough because -3lv is rather dark, though not different enough from -2lv to tell a difference w/o a lightmeter (or you can look inside your picture files, the measured light value is in there). From kr http://www.kenrockwell.com/tech/ev.htm (http://www.kenrockwell.com/tech/ev.htm)

Quote
LV 3 Brightly lit night street scenes
LV 2 Typical night street scenes
LV 1 Dark scenes outdoors at night
LV 0 LV Zero is defined as the light level that requires a 1 second exposure at f/1 with ISO/ASA100 speed film.
LV-1
LV-2
LV-3
LV-4
LV-5 Scene lit by the full moon
LV-15 Scene lit only by starlight.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: dlleno on December 06, 2012, 04:11:42 PM
...I did have a chance to play with 6D outside parking lot, behind business building, around 7PM westcoast. It was quite dark and the light sources were street lights. I compared to my 5D III and I didn't see the advantage of 6D has to offer in term of -3EV AF center point. Maybe it wasn't dark enough?  I shot with my 24-70 f2.8 II lens at f2.8. The outer points were bit slower though.

folks this is not complicated.    The way to test the advantage that the 6D has to offer in terms of a -3EV center point, is to test in -3EV light! 
 
were you shooting in that level of light? I would say never mind trying to correlate with KR or Wikipedia or any other attempt to describe qualitatively what -3EV is.  Maybe its a firefly in a coal mine during power outage, I don't know --  but none of that matters: it turns out  we know what -3EV is!     Does proper exposure require 4 seconds at f/2.8 and  ISO 1600? 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 04:16:30 PM
Hi Dylan-

  I appreciate you taking the time to do some tests of your own. This is what I wanted to read, other low light focusing tests.

  It's going to be very difficult to notice the difference between the 5Diii and 6D for single focusing type tests, both are going to focus in low light in just over a second. Even when going for 30-50 rounds of focusing, the 6D was only marginally better in the central point. Set up a timer and focus back and forth between 2 high contrast targets 50 times and then you will start to see the differences in speed easier.

As a side note, most of the 5Diii's central, top to bottom, middle row, did very well in low light, where the 6D's other squares failed.

As a whole the 5Diii's focusing systems are the best of the bunch (not even close), but when it comes to low light, yes, it does seem the 6D has the edge in that one central square. Its a true pity Canon didn't have more of an upgrade, but the 6D absolute dominated the 5Dii and D600 on that central point in low light.

M
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: ScottyP on December 06, 2012, 05:27:28 PM
Good-natured helpful criticism is great.  But what compells someone to just plain savage someone else's efforts?  What button got pushed?  There is room for more than just one or two experts on this forum, right?  Why waste such considerable talents for precise measurement conducting vain (and metaphorical) comparisons of the size of one guy's "monopod" vs. the other guy's "monopod"?

If someone knows the only proper and relevant way to look at this question, and yet he sits back casting only stones instead of light, is he not denying humanity by not investing the time/effort to do a proper comparison themselves? 

Or, put another way, "is this how we welcome new members to this forum"?

 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: zim on December 06, 2012, 05:35:10 PM
I actually really do appreciate any testing especially real world as I’m very much in the 6D – 5D3 quandary right now but have time on my side. I’m not questioning the effort put in or the results, I just don’t understand the results, apologies for not articulating that very well.

I thought the 6D autofocus in -3EV conditions was a one stop improvement over the 5d Mark III and a two stop improvement over the 5D Mark II? I don't know about the Nikon.
I don't really get testing beyond the rated limit, maybe I missunderstand further explaination of the -7EV thing would be much appreciated. I also seem to recall a video from DigitalRev (in the boxing ring) where the 5D3 excelled against the D600 no where near -3EV?

I watched that vid ---- it was testing the servo tracking of the 3 though, this is one shot focus mode

and that’s the sort of thing that confuses me how can a camera that by all account blows the socks off the D600 in AF Servo tracking not do the same in single point. Does the sensitivity of the points change somehow or is it down to software algorithms in which case isn’t single point the simplest scenario?
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 06:05:07 PM
I think the thing that may have caused the confusion is that EV is often used interchangeably with "stops". There are countless cameras out there that adjust exposure compensation in EV values relative to the current setting, not the absolute standard EV value. I should have described it as relative stops instead, but though the results were still meaningful. I approached it from the perspective of an experienced wedding photographer who has been frustrated with the single point in low light.

As to your quandary about the 5Diii vs 6D, let me ask you this. What kind of shooting are you primarily going to do?

MM
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: dlleno on December 06, 2012, 07:04:37 PM
What we're learning here is consistent with the published specs.  I admit I'm one of those who "stopped reading" when the test wasn't correleated to the standard I was expecting and I couldn't (immediately) tell if the test actually tested the -3EV condition or not.    But that doesn't mean  I quit watching for additional info :D

What isn't so clear to me  is the aparent (empirical evidence only, maybe even just anictotal) slow behavior of the 5D3 to focus in low light situations compared to the 6D (this is not about the AF assist beam with flash).  I'm hearing that the 6D AF (even if slightly less accurate) is faster than the 5D3 under certain situations (which themselves have not yet been acurately described).   Should this turn out to be true,  I wonder if it has anything to do with the fact that the 5D3 AF system is remarkably consistent (low standard deviation per the lensrentals test):  It may have a more elaborate retry/credence algorithm,  and as such require a greater number of handshakes with the lens to acheive that level of accuracy.  It could be that, assuming the evidence is consistent, that the more elaborate algorithm is not as easily satisfied in low light.  To the extent that such a suggestion is true, this strikes me as something Canon might fix or improve silently with a firmware update without officially acknowledging the issue. 
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 07:16:18 PM
That center focus square on the 6D is very, very good in low light. Ill grab it before the others for low light situations.

If you cannot walk away from this post/discussion with that very basic, heart of the matter idea, than nothing I can say will matter to you.

Already done, several posts back...   ;)

Having said that, a generic conclusion that the 6D center point AF performs very well in low light is quite reasonable.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: zim on December 06, 2012, 07:17:17 PM
I think the thing that may have caused the confusion is that EV is often used interchangeably with "stops". There are countless cameras out there that adjust exposure compensation in EV values relative to the current setting, not the absolute standard EV value. I should have described it as relative stops instead, but though the results were still meaningful. I approached it from the perspective of an experienced wedding photographer who has been frustrated with the single point in low light.

As to your quandary about the 5Diii vs 6D, let me ask you this. What kind of shooting are you primarily going to do?

MM

Good question, a big old mixture is the answer I guess! over the years in no particular order architecture/family/aircraft/motor racing.
Next year unusually I have several events weddings/anniversaries/big holidays which are important to me and are without doubt a major driver to new kit. So stuff like the 5D3 flash AF assist issues and low light single point AF are important. That and I’m fed up camera sharing with my daughter. I have SD cards but the 5D3 doesn’t have fast SD, why Canon why!! I do like the faster fps but I want to be confident of focus in low light so lean towards 6D and the IQ looks a little better from what I’ve seen so far, but would the difference be seen on 20x16s I doubt it. I love prints, 20x16 max, If I get a few a year I consider worthy of my wall (yes wife has given me a wall in the house) I’m a happy bunny.
Overall I totally get what a well rounded camera the 5D3 is but boy are there things that just niggle. I love the thought of a camera that I really have to work at learning how to use I think the 5D3 AF system is a challenge, I want to have fun growing into it. I’m thinking of renting over Christmas but I really would prefer putting that money toward glass.

mmmm, you know I think this all boils down to for the most part that I’d be fine with either camera but which camera works best for those special events and that’s where I’m finding AF differences frustrating. The 5d3 should be a no brainer but it just isn’t…… aaarrrgggg
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: jrista on December 06, 2012, 09:43:35 PM
I don't have access to the standard...

In any case, it has no bearing on this discussion.

I do, but you're right.  However, we're talking about small (one stop or in most cases, much less) differences.  My point is that even though it's a relative measurement, labeling the test results as "-7 EV" is pretty darn misleading in light of the specified performance of the cameras being tested.  The difference between -2 EV and -7 EV is a 32-fold difference in light intensity.

It might be interesting to point out that as far as the AF sensor is concerned, the ISO setting does not matter a wit. For that matter, neither does the shutter speed. The only thing the AF sensor cares about is the actual amount of light allowed through the aperture. Shutter speed and ISO only factor in when the image is actually exposed on the image sensor...which is an entirely different aspect of the camera.

The term EV, or exposure value, is just a way to denote a quantity of light by describing it in terms of a given "exposure setting". You effectively have the same "EV" at 1s f/1 as you do at 2s f/1.4 or 16s f/4 or even 1/8s f/0.35! Those are all the same EV. It is usually initially derived at a standards-based ISO setting of 100...but the specific camera settings at which it is generally derived shouldn't change the actual meaning of EV 0, -2, or -3, nor mandate that the only valid way to achieve EV -3 is to use a 1s exposure at f/1 at an ISO of 100. It's just a scalar number that represents a known quantity, nothing else.

That said, I totally agree, indicating that the 6D can AF down to EV -7 is a rogue misrepresentation of both the 6D's capabilities, and a radical misunderstanding or misapplication of what an Exposure Value is. The 6D is clearly rated to AF down to EV -3...that would mean it could AF in as little light as that provided by a full moon (bit less than -2 EV from an illumination standpoint) with an f/1.2-1.4 aperture lens (knock off another 1 EV to reach -3, since we are letting in 1 stop less light than an f/1 lens).
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 06, 2012, 10:51:20 PM
Plenty of criticisms on semantics but why no alternative suggestions on methodology?

Lesson learned.

M

Ps- Jrista- I look forward to seeing your tests.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 06, 2012, 11:11:12 PM
Plenty of criticisms on semantics but why no alternative suggestions on methodology?

Touched on that, as well...and you've got the perfect set of cameras for it!  Got any ND filters?  Set up a target lit at about 2 EV (lighting like you used for Target 2), then start knocking the light down with ND filters.  Alternatively, light a target with a dim desk lamp, then keep moving the lamp further away from the target.  The idea is to keep the same target, but decrease the light levels.  If possible, get them a stop or two lower than your Target 3, so you're below the rated spec of the 6D (and see how far you can push it...the 5DII seemed to go 1.5 stops lower than it's rated spec, and manage to AF, sort of).
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: jrista on December 06, 2012, 11:48:33 PM
Plenty of criticisms on semantics but why no alternative suggestions on methodology?

Lesson learned.

M

Ps- Jrista- I look forward to seeing your tests.

Heh, well, there are definitions and math, and there are ad-hoc tests. There is nothing wrong with an ad-hoc test, so long as it is represented accurately in the correct frame of reference. The definition of EV and the math adds up, and I believe your test is effectively falsified given the facts. We can derive the EV you were actually shooting at based on your exposure settings.

You stated that in your test "0" EV was 1/60s f/2.8 ISO 400. Well, first off, EV 0 cannot really be arbitrarily defined. Officially, EV 0 is "baselined" at 1s f/1. From an available-light standpoint, ISO does not actually matter. So, if EV 0 is officially 1s f/1, then a 1/60s f/2.8 exposure is actually EV 9 (6 stops difference in shutter speed, 3 stops difference in aperture). That is a difference of 12 stops total from an actual EF -3, and a total of 16 stops off from the EV -7 you claim in your test. This makes the assumption that at 1/60s f/2.8 ISO 400, your images were properly exposed (which, based on your blog, they were not...we'll get to that).

Since it is the AF sensor that really matters in the context of DSLR phase-detection AF, the shutter speed doesn't really actually matter either. In this context, the EV designation ultimately refers to a level of illumination on your AF target. If you really want to test AF at -3 EV, you should try it out under the light of a full moon on a clear night with an f/1.4 lens, such as the EF 50mm f/1.4. Assuming you were exposing correctly at 1/60s f/2.8, that would be like photographing a few minutes after sunset during "golden hour"...which is actually a LOT more light than photographing just by moonlight, even though it may appear to be rather dim to your eyes. According to your blog, you were testing indoors with standard house lighting. Indoor illumination is usually rated at around EV 7, however your target was directly in a spot of light illuminated by a very close light fixture that appeared to have multiple bulbs in it, so I'd say EV 9 sounds about right.

You were also underexposing by a significant degree. Again, it should be noted that as far as the AF sensor is concerned, the actual camera exposure settings do not matter, so trying to "simulate" EV -3 by underexposing a photo is not the same as autofucusing in EV -3 or even EV 0. You were actually autofocusing with quite a lot of light. The illumination from the area of your wall that you focused on was probably about EV 9, however you were using an f/2.8 lens rather than an f/1 lens (which, BTW, I am again assuming...Canon cameras always AF at maximum aperture...if your maximum aperture was wider than f/2.8, and you simply chose f/2.8 to force a certain underexposure, then my calculation here will be wrong.) At f/2.8, the AF sensor is effectively working at EV 6. That means that in your test case, instead running the 6D through it's paces at EV 0 (or for that matter EV -3 or -7), you were actually running it through its paces at EV 6.

I don't mean any offense, however your blog writeup about the 6D's AF performance will be eaten alive by anyone who understands how the AF system works, and understands the rough level of illumination of your AF target. The AF Unit, which resides underneath the mirror in the mirror box, contains a special light-splitting lens that directs light from both sides of the lens mounted to your camera onto various phase-detection strips in the AF sensor. The actual amount of light each strip has to work with is minuscule. If we were to describe it in terms of EV's, at EV -3 in your scene each strip is probably working at EV -5 or EV -6, it not less. The mirror will split the light from the camera lens in half, as 50% is reflected up through the viewfinder and the other 50% is redirected through the primary mirror to the secondary AF unit mirror underneath the primary. The AF Unit lens will further split that light for each AF strip. The central cross-type point in the 6D is composed of two diagonal strips, each of which would get around half of the 50% of light directed down to the AF Unit. That is at least two stops, assuming all of this mechanical redirection of light operates at 100% efficiency. Since nothing is perfectly efficient, the phase-detect strips on the AF sensor itself are really probably working at EV -6 to EV -7, when the illumination on your AF target is EV -3. None of this has anything to do with exposure settings...all that matters is the amount of light passing down the lens at maximum aperture. Since the EV scale is baselined at 1s f/1, if you use an f/1.4 lens, the AF sensor is working with even less light. If you use an f/2.8 lens (the minimum required for the central high-sensitivity AF point in the 6D to work), the AF sensor phase-detect strips are working at around EV -10, a vanishingly small volume of light!!! Hopefully this puts the incredible feat of phase-detection AF at EV -3 into, erm, proper light! (...yes, pun intended. ;P)

Now, I can't really say how much illumination the target on the floor under your desk may have had. It is quite possible you were getting closer to EV 0 at that point. However making a guess, even mildly educated as it may have been, is no substitute for using a proper light meter to actually measure the illumination under your desk in EV. It could very well have been that, as dark as it may have looked, the target under your desk was EV 2 or 3, if not higher. There is another caveat here as well. The kind of AF performance testing done by Canon is performed extremely carefully under very tightly controlled circumstances. The ambient temperature must be exact, the kind of lighting used to illuminate the test target must be full spectrum to introduce a proper and predictable amount of illumination, high frequency so as not to introduce a frequency oscillation that could interfere with the test (something that can occur with improperly designed ballasts for CFL bulbs that operate on a 60Hz power frequency), and test targets must be designed with the right level of contrast such that at the incredibly low levels of illumination below EV 0, the AF sensor can actually pick up differences in contrast at all.

I would not be surprised if the cameras failed or were slow to AF on the target under your desk due to a lack of contrast. Your carpet looks to be a dark gray or slightly off gray, with a black + as the target. In EV -3, I highly doubt anything would pick up enough contrast from that to really do anything. If you had stuck the target + on a piece of white paper, that would have created a slightly better test target for testing AF in low illumination, and even then, your at the boundary of the AF units rating, so AF will be spotty at best even in the most ideal of circumstances.

I hate to say it, but your test approach leaves a lot to be desired, and I believe many of the claims (such as EV -7) were fundamentally incorrect. It is highly ad-hoc, and makes use of a lot of guesswork. A lot of the critical factors, such as your definition of EV 0, or even the notion that camera settings have any impact on the AF system at all, are flat out incorrect. I think the only truly valid part of your test was the comparison of the central AF point with the outer AF points, and the conclusion that the central AF point being more sensitive was spot on, if already common knowledge.

As Neuro stated, you have the perfect set of cameras to perform such a test. Maybe, armed with more knowledge from my post here, and further armed with an actual incident light meter to get an accurate EV reading at your AF test targets, you can perform a more accurate and realistic test in a proper frame of reference.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: AudioGlenn on December 07, 2012, 12:10:05 AM
man, u guys are too smart.  i just like to take pictures of things/people.  sometimes, when it's dark, I use a flash =)
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Ryan_W on December 07, 2012, 12:27:29 AM
man, u guys are too smart.  i just like to take pictures of things/people.  sometimes, when it's dark, I use a flash =)

^ This.

Not that I don't appreciate the tests, because I do - and the responses too.  But this one is my favorite.  "things/people."
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: skitron on December 07, 2012, 12:40:21 AM
OK, got my 6D in and have done a bit of subjective testing. First off, IMO, the center point kicks butt and takes names in low light. With a 100L it locks focus in light low enough the IS doesn't seem to be able to work consistantly (if at all) and I can't see what it is I'm even focusing on (I'll let the peanut gallery determine what EV that is  ;) ). The outer points need moderate light (as in a single lamp on in the room), but actually work pretty good on stuff that has some detail, but if it lacks detail, not so good (while the center would focus on the same thing).

Elsewhere I posted about how my 50D body had a substantial "bracket" in which it would confirm focus when manually focusing. It would confirm everything within the equivalent focus range of about 7 AFMA clicks. Meaning when focusing from infinity to closer in would back focus though confirming, while focusing from close to further out would front focus though confirming. And it would confirm anything in between. Meanwhile my 5D2 had a "bracket" of about 2-3 clicks. This 6D seems to be about like the 5D2, maybe a bit worse when manual focus, but autofocus from either direction seems pretty consistent so far with both a 100L and Sigma 50. Not perfect, but if AFMA is right it seems to be completely acceptable even at f1.4 and close up.

All in all, the experience is similar to the handling of a 60D body while getting 5D2 ISO and focus sytem on steroids. Meaning you get something way less than a 5D3 focus system (with the caveat the 6D center is somewhat better in low light), but IMO the 6D system is way better than the 5D2 because it works with so much less light (including the outer points compared to 5D2 outer points) plus seems substantially faster so far. And then there is the ISO, which is also pretty dang good. The video is pretty much the same as the 5D2, i.e. moire city, but certainly useable most of the time. So for me, a nice upgrade to 5D2 for stills, plus lighter and smaller to lug around. And a bit of an upgrade for video in that it will do all i-frame. Of course also not as durable, but seems beefy enough if you don't abuse it.

I did a cursory test of the center point in AI Servo by focusing on a business card about four feet away and then moving the camera towards the card at my best attempt at 1 ft per second and clicking while moving. It locked on with my 100L at 2.8, and that seems encouraging. That was with the default "AF ballistic" settings (which the 5D2 had none of).

Next I tried an outer point the same way. Epic fail. However, it did work when moving the camera about 1ft per second (maybe a bit less) at a distance of about 8 ft and f2.8. So somewhat encouraging that the outer points aren't basically useless like they were on 5D2. Subjectively, the outer points in this cursory test "feel" about like the center point on a 5D2 in AI Servo.

LOL, the real AI Servo test is the dreaded "kids on the swing set" tomorrow... I'll work both center and outers and post the results.

[edit] Just shot some 12800 night video...definite upgrade from 5D2...

[another edit] Another thing I noticed about this body is (1) I don't care for the button layout, and still won't even when I get used to it and (2) for me anyway, there is something about how it is balanced and holds in my hand and the way the shutter button feels that is resulting in way, way less camera shake. Again, that is just me and YMMV, but it is a very welcome thing. It holds true with all three of my lenses, which granted aren't all that different in terms of handling...

To sum it up, for me it was about $400 to do the upgrade from my 5D2 I bought a year ago, given what I sold it for, and so far feels like money very well spent.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: MichaelTheMaven on December 07, 2012, 01:44:43 AM
Plenty of criticisms on semantics but why no alternative suggestions on methodology?

Touched on that, as well...and you've got the perfect set of cameras for it!  Got any ND filters?  Set up a target lit at about 2 EV (lighting like you used for Target 2), then start knocking the light down with ND filters.  Alternatively, light a target with a dim desk lamp, then keep moving the lamp further away from the target.  The idea is to keep the same target, but decrease the light levels.  If possible, get them a stop or two lower than your Target 3, so you're below the rated spec of the 6D (and see how far you can push it...the 5DII seemed to go 1.5 stops lower than it's rated spec, and manage to AF, sort of).

This is actually a pretty good suggestion. I have a couple sets of ND filters and light meter. Doable.

Having all 4 of these cameras is the hard part, putting together and redoing a new test would be simple. Please give me some more ideas and I can put them to another test.

Thanks



Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 07, 2012, 06:32:33 AM
I don't mean any offense, however your blog writeup about the 6D's AF performance will be eaten alive by anyone who understands how the AF system works, and understands the rough level of illumination of your AF target.

^^ this

But, as stated, you've got the tools, and perhaps a better-designed test will provide more accurate answers.

I have a couple sets of ND filters and light meter. Doable.

"Where we did we put that light meter the albino had?"
"Over the albino, I think."
"Well, why didn't you list that among our assets in the first place?"


 :P

Keep jrista's points in mind, too - lens wide open, high contrast target (I mentioned that, before, as well).  You should have been using spot metering before (not sure if you were), but the light meter is definitely the best way to go.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: jrista on December 07, 2012, 11:25:06 AM
"Where we did we put that light meter the albino had?"
"Over the albino, I think."
"Well, why didn't you list that among our assets in the first place?"


 :P

LOL!  :o Where in the world did THAT come from?!? :D
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: DanielW on December 07, 2012, 02:03:17 PM
I understand we're talking about focus speed and sensitivity of the central point, but has anyone tested the outer points with fast glass in terms of focus accuracy? Most of the tests I've found on the web, like Roger's, concern the central point exclusively.
I'm asking this because 11 AF points should be enough for me, if they're all really usable. Maybe the only situation for which I actually need the outer points is when shooting with a very shallow DoF and placing the focus zone very off-center, when composition would change too much and the focus-and-recompose technique would sure fail. (If the subject is not so close to the camera, then the angle changes little when recomposing and I can usually take a sharp pic, even with a shallow DoF.)
I sure appreciate -3 EV sensitivity, but in very low-light situations I won't be playing around with composition anyway, and having one reliable, sensitive central point sounds good enough, IMO. The precision of the outer points concerns me the most, for I can't rely very much on them when shooting with my 60D, even in reasonably well-lit situations.
(Sorry if it's been discussed before; I searched, but found nothing.)
Thanks!
Daniel
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: RDPOE on December 07, 2012, 02:28:03 PM
"Where we did we put that light meter the albino had?"
"Over the albino, I think."
"Well, why didn't you list that among our assets in the first place?"


 :P

LOL!  :o Where in the world did THAT come from?!? :D

A quote from "The Princess Bride" (altered to fit the situation, and much appreciated!!)
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: pj1974 on December 07, 2012, 02:55:24 PM
"Where we did we put that light meter the albino had?"
"Over the albino, I think."
"Well, why didn't you list that among our assets in the first place?"


 :P

LOL!  :o Where in the world did THAT come from?!? :D

A quote from "The Princess Bride" (altered to fit the situation, and much appreciated!!)

Aha!! No wonder I love this forum... it was the Princess Bride connection all along!! :)  Love it.   ;D
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: jrista on December 07, 2012, 03:00:19 PM
"Where we did we put that light meter the albino had?"
"Over the albino, I think."
"Well, why didn't you list that among our assets in the first place?"


 :P

LOL!  :o Where in the world did THAT come from?!? :D

A quote from "The Princess Bride" (altered to fit the situation, and much appreciated!!)

Aha!! No wonder I love this forum... it was the Princess Bride connection all along!! :)  Love it.   ;D

Wow, that brings back memories. I haven't seen Princess Bride in such a long time, but oh, such fond, fond memories! :D
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: neuroanatomist on December 07, 2012, 03:07:33 PM
Just be careful (http://www.canonrumors.com/forum/index.php?topic=9673.msg174273#msg174273).  You have been warned.   :-X
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Area256 on December 07, 2012, 03:16:01 PM
I understand we're talking about focus speed and sensitivity of the central point, but has anyone tested the outer points with fast glass in terms of focus accuracy? Most of the tests I've found on the web, like Roger's, concern the central point exclusively.
I'm asking this because 11 AF points should be enough for me, if they're all really usable. Maybe the only situation for which I actually need the outer points is when shooting with a very shallow DoF and placing the focus zone very off-center, when composition would change too much and the focus-and-recompose technique would sure fail. (If the subject is not so close to the camera, then the angle changes little when recomposing and I can usually take a sharp pic, even with a shallow DoF.)
I sure appreciate -3 EV sensitivity, but in very low-light situations I won't be playing around with composition anyway, and having one reliable, sensitive central point sounds good enough, IMO. The precision of the outer points concerns me the most, for I can't rely very much on them when shooting with my 60D, even in reasonably well-lit situations.
(Sorry if it's been discussed before; I searched, but found nothing.)
Thanks!
Daniel

I suspect the precision of the outer points on the 6D will be at best the same or a little worse than the 60D...

The main problem with precision of the outer points on any camera (save the 5D3), is that they are normally f/5.6 sensitive points, which aren't as precise as the f/2.8 sensitive points sometimes found on the center AF point(s).

All of the 60D's AF points are f/5.6 cross type, and there is an additional f/2.8 cross type sensor overlapping the center point.   Since the 6D's outer points are f/5.6 line sensors, I'd expect, assuming good light and contrast in the right direction, their precision will be about the same.

There will likely differences in how well they respond with different light and target sizes.  And the fact they are only line sensors, will do other things to effect the hit rate.  Just how much of a difference is hard to quantify / no one has tested yet.

Sadly I don't have the equipment to test this formally, but I will have a 60D and 6D tomorrow for some rough analysis.

Also this is kind of the reality of almost all modern AF systems... The outer points tend to have less precision than the inner points, which is annoying since aside from action photography, the use of the outer points is almost always for fast lenses where focus-and-recompose breaks down - and where precision is extra important..  I tend to use LV and manual focus when I'm working with close subjects and fast lenses.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: DanielW on December 07, 2012, 03:43:10 PM
Sadly I don't have the equipment to test this formally, but I will have a 60D and 6D tomorrow for some rough analysis.
Great! Can't wait to see the results!
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: skitron on December 07, 2012, 04:31:19 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: verysimplejason on December 07, 2012, 07:23:48 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

Can you please expound on this?  We want to know what's the difference...  And try using the updated DPP if possible when converting the 6D and 5D2 files.  The jpeg rendering of other software might not be as updated.

Thanks.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: skitron on December 08, 2012, 05:53:13 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

Can you please expound on this?  We want to know what's the difference...  And try using the updated DPP if possible when converting the 6D and 5D2 files.  The jpeg rendering of other software might not be as updated.

Thanks.

I'll try to explain using subjective terms and maybe a technical measurement or two.

To my eyes, everything is underexposed a significant amount and this is verified when looking at the RGB histogram in Capture One. Left side is towards the top and then a smooth slope to zero on the right for typical outdoor shots. Equivalent shots with 5D2 are exposed the way I'd expect and hisotgram is more level with some peaks, as expected.

Color renditions are flat and lifeless to my eyes. This is true just comparing equivalent shots from 5D2 and 6D and looking at the RAWs. Same holds true after working with them in Capture One. Let me put it this way: in adequate light, I'd take my 50D over the 6D in a heartbeat for exposure, color rendition and DR (as lacking as 50D was in DR)...the equvalent shots just look a lot better to my eyes.

I know there is a bunch of chatter about how 6D has better DR, but when shooting it seems the exact opposite and shadows are going black with no detail in the RAWs.

It's hard to quantify this sort of thing, but when I first got my 5D2 I was pleasantly stunned how good any shot looked. It's just the opposite with 6D for me and I'm stunned how un-Canon like all of my shots were. Yes, were. As in its boxed up to go back in exchange for a 5D3.

And I suppose that sums it up for me. As you can see in my earlier posts, I was happy as could be with the AF and low light when I tested it. But then when I started shooting it, it became quickly apparent I'd be sending it back and just spending the extra $ for a 5D3. And for me anyway, I'll spend $400 extra over the eBay price to buy it from B&H so I have no doubt it will have a warranty and I can send it back if I have an issue like I did with the 6D I bought from them...

Of course this is all just my opinion and YMMV. Maybe I got a dud, but bottom line is I'm going 5D3 instead.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: unxpectederror on December 08, 2012, 06:18:46 PM
is anyone quite surprised with the results of the 5d2? i just got one in the other week and it focus's better then my T4i which has 9 cross type point...
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: verysimplejason on December 08, 2012, 08:52:28 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

Can you please expound on this?  We want to know what's the difference...  And try using the updated DPP if possible when converting the 6D and 5D2 files.  The jpeg rendering of other software might not be as updated.

Thanks.

I'll try to explain using subjective terms and maybe a technical measurement or two.

To my eyes, everything is underexposed a significant amount and this is verified when looking at the RGB histogram in Capture One. Left side is towards the top and then a smooth slope to zero on the right for typical outdoor shots. Equivalent shots with 5D2 are exposed the way I'd expect and hisotgram is more level with some peaks, as expected.

Color renditions are flat and lifeless to my eyes. This is true just comparing equivalent shots from 5D2 and 6D and looking at the RAWs. Same holds true after working with them in Capture One. Let me put it this way: in adequate light, I'd take my 50D over the 6D in a heartbeat for exposure, color rendition and DR (as lacking as 50D was in DR)...the equvalent shots just look a lot better to my eyes.

I know there is a bunch of chatter about how 6D has better DR, but when shooting it seems the exact opposite and shadows are going black with no detail in the RAWs.

It's hard to quantify this sort of thing, but when I first got my 5D2 I was pleasantly stunned how good any shot looked. It's just the opposite with 6D for me and I'm stunned how un-Canon like all of my shots were. Yes, were. As in its boxed up to go back in exchange for a 5D3.

And I suppose that sums it up for me. As you can see in my earlier posts, I was happy as could be with the AF and low light when I tested it. But then when I started shooting it, it became quickly apparent I'd be sending it back and just spending the extra $ for a 5D3. And for me anyway, I'll spend $400 extra over the eBay price to buy it from B&H so I have no doubt it will have a warranty and I can send it back if I have an issue like I did with the 6D I bought from them...

Of course this is all just my opinion and YMMV. Maybe I got a dud, but bottom line is I'm going 5D3 instead.

Have you tried using DPP?  I don't think Capture One is updated already to handle raw files from 6D.  Just like Lightroom needs an update or a new profile just to handle other new bodies.  WTH, even DPP needs an update to correctly render raw files from new bodies.  Agreed, maybe you got a bum copy because, I have never seen anyone complain about the DR/IQ of 6D except for underexposing which could be easily adjusted by Canon Support if needed. 

Anyway, good choice.  I'd always say, if you think you've got the money to afford a 5D3, then go for it.  Granted it's more expensive but it's more versatile.  However, for some, I think it will be 6D.  I've got a friend who just got a 6D yesterday.  Hopefully, he brings it to office tomorrow so I can see it and maybe compare it with some cameras from our group.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Area256 on December 08, 2012, 09:56:01 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

I processed a few shoots of the same scene with same settings (ISO 100)/lens with the 60D and 6D, then looked at the RAWs in CPP.  Both were basically identical in terms of color and DR (although CPP was applying the same tone curve so that should be expected).  I don't think there was a major difference between the 60D and the 5D2.  So I'm not sure what's happening in your case.

I also tried pushing the shadows in both, and didn't notice any real difference between the 60D and 6D.  A tad better in the 6D, but nothing to write home about.  The area the 6D really seems to shine is high ISO, where it clearly dominates the 60D.  But again, color looks the same on both.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: Area256 on December 08, 2012, 10:15:13 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

I processed a few shoots of the same scene with same settings (ISO 100)/lens with the 60D and 6D, then looked at the RAWs in CPP.  Both were basically identical in terms of color and DR (although CPP was applying the same tone curve so that should be expected).  I don't think there was a major difference between the 60D and the 5D2.  So I'm not sure what's happening in your case.

I also tried pushing the shadows in both, and didn't notice any real difference between the 60D and 6D.  A tad better in the 6D, but nothing to write home about.  The area the 6D really seems to shine is high ISO, where it clearly dominates the 60D.  But again, color looks the same on both.

I just tried Capture One.  Images look almost exactly the same as CPP.  And I got very impressive shadow detail recovery on the 6D in Capture One.  Sadly I think your camera must be a bad copy.
Title: Re: Canon 6D Dominates Low Light Focusing Test vs 5Dii, 5Diii & Nikon D600
Post by: skitron on December 09, 2012, 03:01:31 PM
...I will have a 60D and 6D tomorrow for some rough analysis.

Let me know what you think of the way 6D renders colors and lighting dynamics. Now that I've moved on from testing to actual pictures, I am not liking what I am seeing in this respect. I'm shooting RAW and the the 6D files have a very different character than do 5D2 files imo, and not in a good way.

I processed a few shoots of the same scene with same settings (ISO 100)/lens with the 60D and 6D, then looked at the RAWs in CPP.  Both were basically identical in terms of color and DR (although CPP was applying the same tone curve so that should be expected).  I don't think there was a major difference between the 60D and the 5D2.  So I'm not sure what's happening in your case.

I also tried pushing the shadows in both, and didn't notice any real difference between the 60D and 6D.  A tad better in the 6D, but nothing to write home about.  The area the 6D really seems to shine is high ISO, where it clearly dominates the 60D.  But again, color looks the same on both.

I just tried Capture One.  Images look almost exactly the same as CPP.  And I got very impressive shadow detail recovery on the 6D in Capture One.  Sadly I think your camera must be a bad copy.

Mine very well could have been a dud but I was thinking I'd like the improved video of 5D3 anyway so just went ahead and did it. I'm sure I'll like the 'even better' AF though the 6D AF was fine in my book.

Yes, the Capture One v7 shadow recovery tools are pretty amazing.