September 23, 2014, 04:38:03 PM

Author Topic: 6D autofocus capabilites: let's bust some myths about it  (Read 59219 times)

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #150 on: December 19, 2013, 12:57:33 AM »

How about a handheld shot indoors in a dark room at 300mm and f/5.6 (with the 70-300L), for .8 seconds at ISO 10,000?  Is that not low light?  If a 5D3 can autofocus in that amount of light, I'll go buy 10 of them tomorrow...

Those settings would result in close to EV +1. The AF working range of the 5D3 is between EV (-) 2 to (+) 18 so yeah ... it will autofocus.

Correct, because I wanted the image to look like the lights were on, even though they were off.  So I used positive exposure compensation. 

canon rumors FORUM

Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #150 on: December 19, 2013, 12:57:33 AM »

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #151 on: December 19, 2013, 01:00:42 AM »
How about a handheld shot indoors in a dark room at 300mm and f/5.6 (with the 70-300L), for .8 seconds at ISO 10,000?  Is that not low light?  If a 5D3 can autofocus in that amount of light, I'll go buy 10 of them tomorrow...
Those settings would result in close to EV +1. The AF working range of the 5D3 is between EV (-) 2 to (+) 18 so yeah ... it will autofocus.

Thanks for the calculation, imho Canon pulled a real marketing stunt with the -3LV af as the 6d defining feature since it's only the center point, and very few people will need this one stop more, ever.

For me it's still useful for silently af'ing animals in very dark conditions w/o af assist for flash shots, and neuro has convinced me that there might be some long expo handheld shots with IS that are -3LV. For tripod shots I'D still take live view focusing with ML focus peaking and "night mode" lv boost over phase af...

As I explained above, I used positive exposure compensation.  So yeah, the actual available light was more like -2 to -3EV.  And this was with a lens that was native f/5.6.  The room was quite dark. 

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #152 on: December 19, 2013, 01:23:48 AM »
Correct, because I wanted the image to look like the lights were on, even though they were off.  So I used positive exposure compensation.

Now just wait here - you're saying that the light level was -2 LV, but with setting +1 positive exposure compensation on your camera you dimmed down the ambient to -3 LV so that only the 6d af would have been able to auto-focus as you theorized with the wager of buying 10 5d3 camera bodies?

Look, you all can calculate the available light all you like.  I don't have a calibrated light meter.  It was a black pepper shaker that I focused on with that center point.  I just looked it up in my camera, and the exposure compensation was +2 EV.  I will post the picture in the next day or two, unedited, but also post an edited version to make the darkness appear how it looked to my eye.  I shot it as a jpeg.  There is white lettering against the black of the shaker that says "pepper", that helped the autofocus.  Also there is a highlight on the left edge of the shaker, but I didn't put the point over that.  It may or may not have been a factor in the focusing.  I was mainly trying to test the IS...it worked, but only for about 1 in 4 of the shots at such a long exposure.  How many stops of IS is 8/10 of a second at 300mm?

J.R.

  • 1D X
  • *******
  • Posts: 1491
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #153 on: December 19, 2013, 01:32:48 AM »

How about a handheld shot indoors in a dark room at 300mm and f/5.6 (with the 70-300L), for .8 seconds at ISO 10,000?  Is that not low light?  If a 5D3 can autofocus in that amount of light, I'll go buy 10 of them tomorrow...

Those settings would result in close to EV +1. The AF working range of the 5D3 is between EV (-) 2 to (+) 18 so yeah ... it will autofocus.

Correct, because I wanted the image to look like the lights were on, even though they were off.  So I used positive exposure compensation.

I'm not sure I understand your post. 
5D3, 6D
16-35L, 24-70L II, 70-200L II, 100-400L, 50L, 85L II, 135L, 24TSE, 40, 100 macro, 600RT x 4
I come here to learn something new, not to learn how bad my gear is - I know that already ;-)!

Marsu42

  • Canon EF 400mm f/2.8L IS II
  • *******
  • Posts: 4571
  • ML-66d / 100L / 70-300L / 17-40L / 600rts
    • View Profile
    • 6D positive spec list
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #154 on: December 19, 2013, 01:37:32 AM »
It may or may not have been a factor in the focusing.  I was mainly trying to test the IS...it worked, but only for about 1 in 4 of the shots at such a long exposure.  How many stops of IS is 8/10 of a second at 300mm?

Sorry, I mis-read your posts (just drinking my morning coffee :-)) and removed it, but not before you could snatch it for a quote :-p ... you're correct, with exposure compensation used (which you didn't mention at the time) you cannot directly calculate back the ambient from only shutter/aperture/iso, so if it was as you said it might have been darker than -2 LV.

Another question is how hard these barriers are, much more likely the camera's ability to af doesn't stop suddenly af -3.000001 LV, and nobody really tested it so we can only take Canon's word on how large the 5d3/6d gap really is.

My experience with the 6d af using the 100L f2.8(!) lens is that the lack of a precise center cross point shows up more at dim light, it af's alright sooner or later, but the precision seems to be worse than at good light unless you're extra-careful to pick a contrast part. With a f4+ lens you won't have these troubles of course.

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #155 on: December 19, 2013, 02:18:32 AM »
It may or may not have been a factor in the focusing.  I was mainly trying to test the IS...it worked, but only for about 1 in 4 of the shots at such a long exposure.  How many stops of IS is 8/10 of a second at 300mm?

Sorry, I mis-read your posts (just drinking my morning coffee :-)) and removed it, but not before you could snatch it for a quote :-p ... you're correct, with exposure compensation used (which you didn't mention at the time) you cannot directly calculate back the ambient from only shutter/aperture/iso, so if it was as you said it might have been darker than -2 LV.

Another question is how hard these barriers are, much more likely the camera's ability to af doesn't stop suddenly af -3.000001 LV, and nobody really tested it so we can only take Canon's word on how large the 5d3/6d gap really is.

My experience with the 6d af using the 100L f2.8(!) lens is that the lack of a precise center cross point shows up more at dim light, it af's alright sooner or later, but the precision seems to be worse than at good light unless you're extra-careful to pick a contrast part. With a f4+ lens you won't have these troubles of course.

Something we can agree on!  I have the same experience as you with your 100 f/2.8, in my same darkly lit room, with my 135 f/2 mounted.  It absolutely refuses to autofocus with just center point, where it will easily AF with an f/4 lens in the same light.  An f/4 lens is how much less light than f/2?

As for the 70-300L, I really must conclude that it just still can't autofocus as fast or in as low of a light, as the 70-200 f/4 (non IS)...even if the 70-300L is zoomed to f/4 at the wider end.  The 70-300L has more trouble all around than the 70-200 f/4.  I hate to sell it, but I can't afford to keep both lenses (also need to sell two of my Sigma lenses...I like them but I can't afford to collect 40 lenses like some of you guys). 

The 70-200 f/4 non-IS, combined with the 6D, absolutely got the best out of the 6D's admittedly limited autofocus and servo tracking ability, in my experience.  I've still not fully explored the 70-300L's servo ability, but given its single shot performance, I have to conclude it also cannot do what the 70-200 f/4 could do.

The 70-300L seems quite a lot sharper, except all the way at 300mm.  It seems to have slightly more CA, but it's not a problem.  It seems to have quite a lot more contrast (similar to the 135 f/2 and that's saying something, especially for a zoom!!)...And again, it most definitely is the most flare resistant lens I've ever used.  The reviews that talk about this are almost understating it.  I can't believe I'm pointing this thing nearly into the sun and no flare, no significant hazing (ghosting?). 

The IS of the 70-300L can be spectacular (.8 seconds hand-held at 300mm)...but this is NOT the norm.  And if I focus-recompose and I'm not in panning mode, the IS gets upset and I have to let it settle for probably 1.5 seconds before I snap the picture.  It does seem to have some mirror slap compensation (which is impressive in itself at this price level imho)...But again, it's nothing like the best IS I've personally experienced so far, the 200 f/2L.  That was in another realm...however the 200L's IS was probably only reliably repeatable while hand-held at 1/10 or 1/13 of a second, and faster.  The 70-300L is similar at 1/30 or 1/40 of a second...at least at 300mm.  In the middle, around 100-150mm, it might be repeatable down to 1/20 second.  At the wide end it seems slightly better than the long end, but not as good as from 100-150mm.

Marsu42

  • Canon EF 400mm f/2.8L IS II
  • *******
  • Posts: 4571
  • ML-66d / 100L / 70-300L / 17-40L / 600rts
    • View Profile
    • 6D positive spec list
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #156 on: December 19, 2013, 02:33:46 AM »
I've still not fully explored the 70-300L's servo ability, but given its single shot performance, I have to conclude it also cannot do what the 70-200 f/4 could do.

I've already read multiple posts complaining about 6d+70-300L, but I have to say I can't see the problem - but maybe that's because I've only got "tricky" lenses to begin with and no good "standard" comparison. Unless I use multipoint-tracking in which the result is pitiful, the 70-300L is ok at single-point tracking, well, as ok as I'd expect the 6d to get at all.

The one issue I can see that the 70-300L exposes the 6d not to be a closed loop system. I just tested it in a dim room, it af's a first step, then thinks again for some microseconds, then af's a second step - just like the Tamron 24-70/2.8 does. I also just did a quick comparison on the 60d: the speed isn't a big difference, however the final 2nd af step seems to be bit faster on the 60d, but it's also there.

canon rumors FORUM

Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #156 on: December 19, 2013, 02:33:46 AM »

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #157 on: December 19, 2013, 02:40:04 AM »
I've still not fully explored the 70-300L's servo ability, but given its single shot performance, I have to conclude it also cannot do what the 70-200 f/4 could do.

I've already read multiple posts complaining about 6d+70-300L, but I have to say I can't see the problem - but maybe that's because I've only got "tricky" lenses to begin with and no good "standard" comparison. Unless I use multipoint-tracking in which the result is pitiful, the 70-300L is ok at single-point tracking, well, as ok as I'd expect the 6d to get at all.

The one issue I can see that the 70-300L exposes the 6d not to be a closed loop system. I just tested it in a dim room, it af's a first step, then thinks again for some microseconds, then af's a second step - just like the Tamron 24-70/2.8 does. I also just did a quick comparison on the 60d: the speed isn't a big difference, however the final 2nd af step seems to be bit faster on the 60d, but it's also there.

Interesting, I've not noticed a two step process.

Marsu42

  • Canon EF 400mm f/2.8L IS II
  • *******
  • Posts: 4571
  • ML-66d / 100L / 70-300L / 17-40L / 600rts
    • View Profile
    • 6D positive spec list
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #158 on: December 19, 2013, 02:44:52 AM »
Interesting, I've not noticed a two step process.

Compare it to a "closed loop" system like 1dx/5d3 if you have the opportunity, these don't need any further feedback from the lens and can tell it precisely where to focus in one step, while "open loop" systems use a second micro-step depending on circumstances. This is the big advantage of Canon's newest af system, though it only works in combination with the latest lenses.

CarlTN

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2227
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #159 on: December 19, 2013, 02:47:07 AM »
Interesting, I've not noticed a two step process.

Compare it to a "closed loop" system like 1dx/5d3 if you have the opportunity, these don't need any further feedback from the lens and can tell it precisely where to focus in one step, while "open loop" systems use a second micro-step depending on circumstances. This is the big advantage of Canon's newest af system, though it only works in combination with the latest lenses.

My cousin who owns the 1DX does not have any of the newest lenses.  You're welcome to bring all of yours over sometime!

ashmadux

  • Rebel T5i
  • ****
  • Posts: 144
  • Art Director, Visual Artist, Freelance Photography
    • View Profile
    • Edward Ofori Photography
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #160 on: December 28, 2013, 02:16:20 PM »
Not to cut into the AF conversation, but ive finally gotten a chance to take some test shots with a replacement 6d. The first ones AF/sharpness was atrocious. Much better, but its not 'there' yet. I havent AFMA'd though.

The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

Be the best you, screw everything else.

Skirball

  • 7D
  • *****
  • Posts: 364
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #161 on: January 02, 2014, 04:15:57 PM »
The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

So, you're allowed to litter any time other than 8:30 - 10:00 on Mondays?

Chuck Alaimo

  • 1D Mark IV
  • ******
  • Posts: 963
    • View Profile
    • Chuck Alaimo Photography
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #162 on: January 02, 2014, 04:16:57 PM »
The screen is a 1:1 screen shot, non- developed, adobe bridge 100% raw file preview. Reference 24-105.

So, you're allowed to litter any time other than 8:30 - 10:00?

LOL!!!!
Owns 5Dmkiii, 6D, 16-35mm, 24mm 1.4, 70-200mm 2.8, 50mm 1.4, 85 mm 1.8, 100mm 2.8 macro, 1-600RT, 2 430 EX's, 1 video light

canon rumors FORUM

Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #162 on: January 02, 2014, 04:16:57 PM »

Tonywintn

  • Power Shot G16
  • **
  • Posts: 14
  • Art for the sake of art
    • View Profile
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #163 on: January 05, 2014, 07:29:34 PM »
I went to a college women's basketball game yesterday and got a number of nice shots using my 6D.  This was my first time shooting a sporting event since the early 1980s.  Some background:  I used to shoot sports when I was in college in the 1970s for the local newspaper.  I freelanced college and high school football and basketball games going wherever the Sports Editor sent me.  I earned much needed cash doing that.  I used my 35mm camera with a 50mm f/1.4 lens back then for most shots and push processed to ASA1000 in order to use available light.  Flash wasn't allowed at most sporting events.  Fast forward to yesterday:  My Canon 6D with 50mm f/1.4 lens (just like the old days) set on AI Focus.  A momentary lag on each shot as I pressed the button so that the camera could focus.  I got a number of nice action shots and in focus.  A couple focused on players behind the action.  All and all, not bad.  I switched to AI Servo and multi-shot mode.  Now we're talkin'.  Focus hit on nearly every shot.  I have a few that focused on the bleachers or on the wrong players; but 90% dead on.  I used 1/250 and f/2.8 with the 50mm and stayed with 1/250 but shot wide open with my 70-300mmL at f/5.6.  ISO was between 2000 and 6400.  So pretty good lighting on the floor.  The shots with both lenses were excellent.  My experience compared to the 70s is what a difference technology makes.  I used to go through a lot of B&W film to bag a few great shots.  My keeper rate was way higher with today's technology.  I was also glad to see I still have the knack.  btw- would I get in trouble posting a few of these pix from a public sporting event?  Do we need released to do that?  What are the rules?
Canon 6D, 24-105mm f4L,50mm f1.4,70-300mm f4.5/5.6L,17-40mm, f4L, G10

ashmadux

  • Rebel T5i
  • ****
  • Posts: 144
  • Art Director, Visual Artist, Freelance Photography
    • View Profile
    • Edward Ofori Photography
Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #164 on: January 06, 2014, 12:52:26 PM »
If you can't get decent pictures out of a 6D then there is some serious wrong with you as a photographer!!

+1, and I'd even expand on that: you can't get decent pictures out of any *Rebel* then there is something seriously wrong with you as a photographer.

Post like this are ridiculous. Also considering that my rebels have been super reliable, yet 7d/6d have been nothing but trouble in the Af department. My Xsi focus put these higher level bodies to shame...and im ashamed to have to say that. :(
Be the best you, screw everything else.

canon rumors FORUM

Re: 6D autofocus capabilites: let's bust some myths about it
« Reply #164 on: January 06, 2014, 12:52:26 PM »