5D2 AF in dim light: :-(
by AFS on Dec.20, 2008, under cameras
So this week I got a change to use the 5D2 for a real shoot, using daylight which is my favorite way to shoot. Unfortunately, for full body shots, I got many frames where the model is out of focus. I counted 50% of the shots out-of-focus using the outer AF points and my 85 1.2 on a tripod! A few were due to movement of the model, but mostly just due to misfocus with the outer AF points which were positioned over her face. Fortunately I noticed this fairly early on and switched to the center AF point, which worked fine.
A week prior I found that these outer AF points work like a charm with the 85 1.2 lens in fairly bright light outdoors, but they apparently are not stellar performers when it’s dim. This is very disappointing in a $3000 camera. You will definitely do better with the 1Ds2 or 1Ds3 if you are shooting dim available light as I often do. However if you are in a situation where you can use the center point 100% of the time the 5D2 AF should work fine.
This was not nearly my most adventurous photography, but the exercise did show me that the 5D Mark II files look fine in low light (when focused correctly,) as the 1Ds3 files do. Though the bad AF is an issue, I think the main problem here is that the red focus indicator lights up as if the shot is in focus, when it’s not. The 5D2 seems not to work better than the original 5D in terms of low light AF using the outer AF points. But at least with the original, the AF point does not light up if the shot is not focused. For $3000 it should indeed be better. Too bad they didn’t have the nuts to put all cross-type sensors in this camera like the $1000 40D has! 
here’s one example of the AF issue:
off-center-af-issue-5d2.
And here’s one which focused ok:
5D Mark II
Here is an older shot where the 5D Mark I focused effortlessly, even though it was darker:
5D Mark I
UPDATE 12-22-2008
OK, so I just combed through a bunch of old shoot using the original 5D in essentially identical situations as the aforementioned bad AF shoot with the 5D2.
Where the peripheral AF points were used on the old 5D, I counted 40 in focus shots, 10 out of focus in one example; 40 in focus vs. 7 out of focus in another; 20 in focus vs. 4 out of focus in a third shoot. The lenses used ranged from the 50 1.4, 70-200 2.8, 85 1.8 – all used in the neighborhood of 1/30 or so, ISO 200, around f 2.8 or 4, and all on tripods. These were all full body shots like the example posted earlier in this thread. Facial features were used as focus points.
As I suspected, the older camera was FAR better at achieving focus with the non cross-type AF points in non-bright situations. So either this particular camera is not right, or something went awry with the AF update in the new camera.
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December 20th, 2008 on 7:51 pm
Bummer…thanks for sharing.
December 21st, 2008 on 10:43 pm
Ron asked me to add my impression on how the Autofocus perform on the Sony a900 when shooting fashion in studio.
I have been a Canon user for about 5/6 years, and Nikon, Mamiya and Hasselblad user for much longer. I am still using Canon cameras so often that I would say I’m pretty much in symbiosis with 1ds series and I also owned the previous canon 5d, but recently I got a Sony a900 with a few prime lenses and so far I used it with the 85mm 1.4 Zeiss, and the 135mm 1.8 zeiss and Sony 50mm 1.4.
I have used the a900 on a couple of fashion shoots in studio, with strobe flashes and the focusing was made under modeling light only, without any help from extra continuous lighting.
The a900 has a very similar sensors layout and joystick to the 5D2. In general it lock focus very easily on all the focus sensors and occasionally it hesitates a little before locking when using the outer AF sensors, but that happens very rarely and when the sensor is placed on a flat area without contrast like a white shirt or if the detail is far and small. Normally it focus precisely with a rate of sharp shots well above 90% in “single shot” mode using any of the AF sensors. When working with the model moving and using “continuous” AF mode, it gives a reliability of about 80% shots in focus and almost all of those are tack sharp. It does not give you any “false” focus shots where you think the AF worked properly and then when you check the photo is pretty much out of focus to be unusable. Normally the 135mm zeiss focus faster and with less hesitation than the 85mm and 50mm.
So far with the limited use I had I would say that even if the a900 does not have a sophisticated AF system as some other cameras, it simply works with a very good reliability. It was actually better than what I expected.
December 23rd, 2008 on 12:31 am
Hmm, that’s too bad, not good to hear. My 5D II, so far, is giving me more in focus shots than I was getting with the 5D (original). What I was noticing is that *specifically* the outer points seem a bit better than on the old camera and issues of front- or back-focusing seem to be minimized.
Manual focus also seems *way* better than on the 5D I. On the 5D 1 I could never tell what was in focus below about f4, maybe 2.8. Maybe it’s the larger viewfinder or coverage or whatever on the 5D II but I seem to be able to get a good ratio all the way down to f2! Below that and I think you’d better have the special screen for manual focusing (which I plan to investigate when I can find one).
Back to autofocus, now I haven’t done this yet, but maybe you should look at the AF lens micro-adjustment feature on the 5D II. It’s supposed to prevent exactly what you’re talking about if I understand it correctly. It would be interesting to hear if it makes any difference at all. I would say maybe give that a try with a favorite prime lens. I agree that it shouldn’t be necessary on a $3k camera, but at least there’s something to try short of sending it to Canon to have it calibrated.
December 23rd, 2008 on 7:53 am
Hi Geoff, thanks for posting. It’s funny how people’s experiences vary so widely with these cameras. I never really had any focusing issues with my 5D Mark I, while lots of people apparently did.
In any case I feel that the issue with the 5D Mark II can not be fixed by micro-adjustment because as it stands the focus works well across lenses and using any of the AF points in bright light . It also works well in the dark as long as only the center point is used. The micro-adjustment works by adjusting the lens for all time, not just in darkened conditions. I tried it the other day and it simply throws the AF off for all focus points, all the time.
December 25th, 2008 on 12:24 pm
I’ve always have problems with an old 5d. I had a few of an old 5d – everyone had that problem in dim light. Center point works better, but not perfect. But I work very often at iso800, 1/60s f1.4-1.8.
I think, that better idea is to buy used 1ds mk2.
December 25th, 2008 on 9:40 pm
See I never had issues with the focus no the original. And I already have a 1Ds3, but what I really want is a smaller camera with good focus and a big file. I guess I am going to go back to my 5D1 until (hopefully) this focus thing is resolved by firmware. Otherwise I will sell it and stick to the 1 Series, or get a Nikon D700 to use as my smaller camera. It’s really too bad they crippled this thing with bad focus.
December 26th, 2008 on 10:32 am
Ron,
Any chance the outer points would be more accurate in low light with the AF assist of a 580ex or ste-2?
Perhaps this would not be your preferred shooting setup, but it would be great to hear your opinion on this for those of us that do use this kind of rig.
Thnx
December 26th, 2008 on 1:55 pm
I’d be interested in that (what DPL suggested)too Ron..
Kind regards and thanks for the heads up.
December 27th, 2008 on 9:34 pm
[...] up on the Internet. Can’t say I’m surprised. And then, some fashion shooter discovered that the outer focus points on the 5D2 don’t work very well in low light. Can’t say I’m [...]
December 28th, 2008 on 4:42 pm
DPL and Bart, maybe I’ll try it next week, but I would not be willing to work like that myself. The idea of working with this camera instead of my 1Ds3 is to have a smaller, lighter body. Putting a flash on top adds makes it unwieldy in my opinion. Plus is makes working with studio strobes more complex. We’ll see.
December 28th, 2008 on 11:15 pm
Hi Ron,
Thanks, I do hope you get the chance to try it.
With each new camera, Canon always seems to be five steps forward, then two steps back in other not-so-important areas like focus.
December 30th, 2008 on 5:39 pm
[...] a wedding pro had difficulty getting his POSED shots in focus. And recently, a fashion photographer got a chance to experience first hand just how bad the AF system of the 5D Mark II really is. Check out the post on his website. Here’s a quote: So this week I got a change to use the [...]
January 7th, 2009 on 8:55 am
[...] 12/28/2008: Apart from the wedding pro which I mentioned above, recently a fashion photographer got a chance to experience first hand just how bad the AF system of the 5D Mark II really is. Check out the post on his website. Here’s a quote: So this week I got a change to use the [...]
January 12th, 2009 on 11:29 pm
I think you are thinking like sukrat, but I think you should cover the other side of the topic in the post too…
January 15th, 2009 on 3:00 pm
I am amazed with it. It is a good thing for my research. Thanks
January 20th, 2009 on 1:38 pm
I am unable to understand this post. But well some points are useful for me.
January 26th, 2009 on 9:03 am
interesting inputs – I’m not spending as much time as I’d like in front of the 5D2 so I’m not sure i can give any real feedback, but i’ve added this to the 5D wiki at http://planet5d.com We’ve got more 5D reviews/still/video samples than anywhere else on the planet.
February 10th, 2009 on 8:43 am
Ron, I found my one lens that has trouble with the 5D MkII is the 85 1.2 (original).
It was WAY off. Microfocus adjustment seemed to solve the problem–though you’ve probably tried that solution already.