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Author Topic: 6D Autofocus not impressive  (Read 87418 times)

BrettS

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Re: 6D Autofocus not impressive
« Reply #30 on: March 26, 2013, 06:06:21 PM »
One thing I don't get is before the 5DMIII came out, people were doing fine with 5DMII. I did. I shot a lot of wedding with 5DMII. My clients are happy, and I'm proud of my work. It's still a great camera for me. I bet it is still an awesome camera for many working pro out there. Yet, the 6D is a little better overall but it seems like everyone is trying to bash the camera. If you could take great pictures with the 5DMII, you can take great picture with the 6D. I know its AF is not in the same league with the 5DMIII but it is still a great camera IMHO.
It has its limit, but I've seen many great bird in fly photos taken with the 5DMII. I don't see any reason why the 6D can be any worst than the 5DMII. Or suddenly, the 5DMII became a worth-less camera at the end of its cycle.

This.

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Re: 6D Autofocus not impressive
« Reply #30 on: March 26, 2013, 06:06:21 PM »

elflord

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Re: 6D Autofocus not impressive
« Reply #31 on: March 26, 2013, 06:09:03 PM »
I rented a 6D camera body to take helicopter skiing in Canada. I brought my 24-105 f/4, 40 f/2.8, and my 50 f/1.8 lenses. I found the autofocus to be slow with all 3 lenses, especially in lower light. I really experimented by changing many of the autofocus parameters and resetting the rental body to factory settings to make sure nothing was amiss. I found the 6D autofocus to be for the most part as good as my Rebel 550D with each of my lenses. I was really disappointed because a want a new body to replace my Rebel.  Lensrentals.com checked the 6D and found it up to factory specs.  Looks like I may have to pony up for the 5D m III.  Does anyone think the climate and elevation had anything to do with the slow AF?  Or does the 6D really have a mediocre AF?

Can you provide more details ? How were you using it ? Green box mode ?

elflord

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Re: 6D Autofocus not impressive
« Reply #32 on: March 26, 2013, 06:09:41 PM »
If you read my original post, I rented the 6D to try it out. I did not buy it.  I was seeking other opinions because many have said the 6D's AF was in the same ballpark of the 5D m III. I found this not to be the case with the kit 24-105 f/4.

Have you also tried the 5DIII ?

Skirball

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Re: 6D Autofocus not impressive
« Reply #33 on: March 26, 2013, 06:19:50 PM »
I tried to use my 6D to take a picture of a moving subject and the AF motor spontaneously combusted.  True story.

MintMark

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Re: 6D Autofocus not impressive
« Reply #34 on: March 26, 2013, 06:20:14 PM »

There still is no (zero, 0) full cross point at all @f2.8 (only @f4+), so precision with fast lenses esp. on moving objects should be very bad.


I think that's a little harsh. With a faster lens you do still have the centre cross point... it's just no more accurate than with a slower lens. However, I understand that it is designed to calculate focus to within one depth of field. Since depth of field is shallower it means the focussing is more accurate in absolute terms. Also, the 6d centre point does become more accurate in one direction, so if your scene accommodates that then you get focus to within a third of the depth of field.

Marsu42

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Re: 6D Autofocus not impressive
« Reply #35 on: March 26, 2013, 06:33:08 PM »
There still is no (zero, 0) full cross point at all @f2.8 (only @f4+), so precision with fast lenses esp. on moving objects should be very bad.
I think that's a little harsh. With a faster lens you do still have the centre cross point... it's just no more accurate than with a slower lens.

I admit my annoyance with the 6d af means that I might be a bit simplistic - but in fact many people seem to think that the 6d has a xxd-style center cross point (extra sensitive for f2.8 lenses) while with the 6d the opposite is true (non-cross overlay). Then think of the 1dx/5d3 double-cross points - doh. But of course for years photogs managed to shoot with the 5d2 center af just fine, and the 6d has improved the accuracy a bit (see lensrentals).

The imho real unforgivable point is Canon porting the 5d2 outer points 1:1 to the 6d when as far as I researched it you should better not use these, not only in dim light but because their precision and pattern detection is so bad and just behind the times. That won't hinder me from buying a 6d, but just saying...

neuroanatomist

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Re: 6D Autofocus not impressive
« Reply #36 on: March 26, 2013, 07:48:24 PM »
I admit my annoyance with the 6d af means that I might be a bit simplistic - but in fact many people seem to think that the 6d has a xxd-style center cross point (extra sensitive for f2.8 lenses) while with the 6d the opposite is true (non-cross overlay). Then think of the 1dx/5d3 double-cross points - doh.

In fact, xxD bodies since the 40D have been 9 cross-type at f/5.6 with a dual-cross center point (f/2.8 'x' superimposed on the center f/5.6 '+').  Moreover, even the T4i/650D and T5i/700D now have that AF sensor.  The 1D X/ 5DIII have a vertical row of five of those dual-crosses, not just one in the center.  As you state, the 6D doesn't even have that.  Just sayin'.
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Re: 6D Autofocus not impressive
« Reply #36 on: March 26, 2013, 07:48:24 PM »

Marsu42

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Re: 6D Autofocus not impressive
« Reply #37 on: March 26, 2013, 08:07:30 PM »
As you state, the 6D doesn't even have that.  Just sayin'.

As you're the expert on Canon gear: Are there any redeeming reasons for Canon implementing the 5d2 af in the first place and then copying it to the 6d (+2 non-cross points, +low light af)? Maybe designing an af array for ff is more complicated/expensive - even though the af spread on 5d2/6d isn't very large?

gimmeadeal19

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Re: 6D Autofocus not impressive
« Reply #38 on: March 26, 2013, 09:10:53 PM »
No elflord, I strictly used it in a custom setting sarcastic mode.

I was on a ski trip away from my kids so I had plenty of time to use the 6D.  I shot it with several different modes and AF adjustments. Too many to list. I rented it for 10 days and did a variety of shooting. My point is for a current Canon model the AF was no improvement over my 550D.

I did rent a 5D m III on a trip to NYC last Thanksgiving and it was everything it was cracked up to be.  My purpose for renting the 6D was to see if my needs could be met with a less expensive body. They were not.

weixing

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Re: 6D Autofocus not impressive
« Reply #39 on: March 26, 2013, 09:24:32 PM »
Hi,
   When 6D is launch, Canon already mention that 6D AF system is design to be low-light AF priority rather than AF speed and they cannot put in more cross point due to the larger AF element require for good low-light AF performance.

http://www.imaging-resource.com/news/2012/09/20/qa-with-canons-mike-owen-behind-the-scenes-in-developing-the-6D-and-whats

   Have a nice day.

x-vision

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Re: 6D Autofocus not impressive
« Reply #40 on: March 26, 2013, 10:45:03 PM »
Maybe designing an af array for ff is more complicated/expensive - even though the af spread on 5d2/6d isn't very large?
If Canon wanted to invest in a new AF system, they would have done it.
But they obviously decided to reuse the 5D/5DII AF system.

The savings for Canon here come from reusing a mature, fully tested AF module and mirror assembly.
This saves them a lot of money for R&D, testing/validation, and subsequent support.

FYI, here are the 6D and 5DII AF sensors side by side.
The 6D clearly has a new sensor ... but one with an identical floorplan as the 5DII sensor - presumably to fit in the existing AF module.



Source: http://www.phreekz.de/wordpress/2012/09/canon-af-vergleich-2012/

neuroanatomist

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Re: 6D Autofocus not impressive
« Reply #41 on: March 26, 2013, 11:48:15 PM »
As you state, the 6D doesn't even have that.  Just sayin'.
As you're the expert on Canon gear: Are there any redeeming reasons for Canon implementing the 5d2 af in the first place and then copying it to the 6d (+2 non-cross points, +low light af)? Maybe designing an af array for ff is more complicated/expensive - even though the af spread on 5d2/6d isn't very large?

Well, first off there was no 'implemented AF' in the 5DII - Canon simply reused the AF sensor from the original 5D.  Many people compare it to the 20D/30D AF, but of course the sizes are different so the design is different. The theory of the assist points was nice - 6 'invisible' points to help with servo tracking. But in practice, it didn't work well, I suspect in part because of a slow AF chip and weak algorithms - and I bet they reused the whole system (AF chip and code) from the 5D in the 5DII, meaning a really old AF system. For sure it couldn't track well, and enabling the assist points (which are off by default) didn't seem to help.  As for why, reusing the 5D's AF saved development and production costs. Similarly, when the 40D got a new AF array, the 20D/30D's system went to the Rebel/xxxD line, and eventually the 40D/50D/60D's AF went to the T4i/650D (which I expect means we'll see something new in the 70D, my money is on 15 points, 9 crosses </speculation>).

The 6D got a similar system, looks like a modification of the basic 5D design. No more assist points (too bad, IMO, because with a modern AF chip and current algorithms, those tightly-clustered points may have been effective.  I'm not sure I buy the bit about needing 'elements of the AF system to be larger' to support -3 EV. AF point size and threshold determine micro lens size, low light is more about signal amplification, and given the density of the 5DIII/1D X AF sensor at -2 EV compared to other bodies at -0.5 EV, I don't see it. 

Why 11 points on the 6D?  I'd say pure marketing. The spread is no greater than the 5DII, just two extra points stuck in there.  But consider the 6D's market position - 'entry-level FF'. Targeted to Rebel/xxxD and xxD users looking to 'go FF'. So, the target upgrade audience all have bodies with 9 AF points (and 18 MP sensors).  So, give them 11 AF points (and 20 MP).  Canon's marketing department understands that for most consumers, quantity trumps quality - the former is a simple 'more is better' and can listed as a top-line spec and be printed on a display placard at Best Buy, the latter requires some technical understanding (e.g., why 9 cross-type points are better than 1 cross type plus 10 lines).  </cynicism>
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verysimplejason

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Re: 6D Autofocus not impressive
« Reply #42 on: March 27, 2013, 02:21:16 AM »
Maybe designing an af array for ff is more complicated/expensive - even though the af spread on 5d2/6d isn't very large?
If Canon wanted to invest in a new AF system, they would have done it.
But they obviously decided to reuse the 5D/5DII AF system.

The savings for Canon here come from reusing a mature, fully tested AF module and mirror assembly.
This saves them a lot of money for R&D, testing/validation, and subsequent support.

FYI, here are the 6D and 5DII AF sensors side by side.
The 6D clearly has a new sensor ... but one with an identical floorplan as the 5DII sensor - presumably to fit in the existing AF module.



Source: http://www.phreekz.de/wordpress/2012/09/canon-af-vergleich-2012/

I'm sorry but they don't have identical floorplan.  It might look as if the same but the there are definitely more connections inside the 6D.  Notice the amount of lines in both the upper and lower portion.  This means that something is different in their logic implementation.

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Re: 6D Autofocus not impressive
« Reply #42 on: March 27, 2013, 02:21:16 AM »

Marsu42

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Re: 6D Autofocus not impressive
« Reply #43 on: March 27, 2013, 03:58:09 AM »
But consider the 6D's market position - 'entry-level FF'. Targeted to Rebel/xxxD and xxD users looking to 'go FF'. So, the target upgrade audience all have bodies with 9 AF points (and 18 MP sensors).  So, give them 11 AF points (and 20 MP).  Canon's marketing department understands that for most consumers, quantity trumps quality

Great, thanks for the conclusive information - this goes into my personal "sticky" posts, and coming from you I guess there really aren't any hidden or redeeming facts except the obvious about the 6d af system - it's really a quick/reused minimal r&d system (thanks, Canon).

Chuck Alaimo

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Re: 6D Autofocus not impressive
« Reply #44 on: March 30, 2013, 04:28:00 PM »
So we'll see what this thing can do...

Please tell us your experiences, I'd be interested to hear from a pro if the 6d is able to do a wedding (I expect it does, after all the 5d2 was able to and the 6d center af is more precise and should be faster at lower light).

@Marsu

not wedding tested yet, and the wedding I am doing is going to be small, ceremony only and in buffalo's botanical gardens - I will be using it but it's not the fullest wedding test I can do.  But, I've had the rental body now for a full day, and have been putting it through some tests in conditions I may find at a wedding.  Daytime, midday, not the ideal time to be shooting, but, weddings don't occur in prime shooting hours, so I thought a good test was midday street style candids.  Here are some results
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Re: 6D Autofocus not impressive
« Reply #44 on: March 30, 2013, 04:28:00 PM »