Canon 1D MKII Focus Question

[dpanicc1]

I was shooting in a relatively low light reception a while back and noticed that on focus lock setting the focus struggled a little and frankly wasn't fast enough w/24-70 L 2.8. I then switched to servo and of course the shutter will release but focus isn't a sure thing. But what I learned was the MKII seems to do a whole bunch better than the 10D in terms of focus accuracy in servo mode, and, the ability to release the shutter at any time is great.

I am just wondering what others do with the MKII in low light in terms of focus mode, and if others have seen this issue. Any thoughts at all?

Thanks,
dan

[Cadwell]

Focus in low light is going to suffer with any camera using a passive AF mechanism. I've found the 1D MkII to be very good (and apparently the latest firmware update helps).

Were you using a flash? If not, and you're going for natural light shots one possible help could be to use a flash unit in order to get the benefit of it's focus assist beam but set it not to fire the main flash via custom functions (can't remember the CF number right now and I don't have the manual handy).

[primoz]

For most of things I'm shooting there's usually enough light for AF to work (at least on 1d and 1dmkII) or I just use flash. I'm lucky to shoot sport so there has to be enough light anyway :) In those few occasions when flash is out of question and it's too dark for AF to work (there's limit for everything... unfortunately) I just switch to manual. AI server doesn't solve anything since if it's not enough light for AF in one shot then it won't be any better in ai servo either. But yes it allows you to shoot even if focus is not achived.

[scottbergerphoto]

There has been a great deal written, mostly complaints, about the low light focusing of the 1DMII. You can find a number of threads on the issue at www.robgalbraith.com , in the 1DMII section . The line from Canon via Chuck Westfall, Director of Technical Information, is that Canon cameras in general will have some deterioration in AF in low light, low contrast situations by virtue of it being a Passive Autofocus System. I did some testing of my own and found that the 1DMII is about the same as the 20D and faster then the 10D. Using CFn. 17-1 which is very useful in AI Servo and good light, really slows down AF by giving the camera additional AF points to use other then the Manually selected one.
I suggest:
1. Manually selected center AF point.
2. Fast lens to take advantage of Cross Type Sensor.
3. CFn. 17-0
4. AF assist beam from 550/420/STE2 if needed.
Regards,
Scott

[dpanicc1]

Well thanks for all the great comments. I'll try to answer a few here. Yes, I did have the 550EX on the camera. I also had the old firmware at that time and have since installed the lastest version but really have not tested it yet. So I am optimistic that will help.

The servo mode does help (and it did help) because it uses, correct me if I am wrong, the center focus point. It probably helped due to what Scott said: less focus points easier for the camera to decide. Plus, with the right f-stop (in servo mode) , you can afford to focus on someone's shirt sleeve and not their eyes; being able to release the shutter at the exact moment is important.

I'll check some of the ideas here--thansl all--and check out www.robgalbraith.com for more information. I am hoping the newer firmware makes a difference.

Thanks,
Dan

[scottbergerphoto]

In AI Servo, 45 pt AF, the camera shuts down all AF points but the Center one. Once it locks focus, it tracks the subject with all 45 points. In AI Servo, Manual focus Point selecton, the camera will only use the focus point you manually selected to lock focus and track the subject. If you select CFn. 17-1, the camera is able to use the AF points immediately adjacent to the manually selected one to lock focus. This slows AF operation in low light.

I havent noticed any difference in AF speed with the new firmware.
Scott

[KennyG]

Dan, the problem isn't a new one and has existed in DSLR terms since the D30 and I even had it with a 1N HS film camera. For AF use single point only, with assist from a 550EX or STE2 and other than that, it is down to squinting through the viewfinder and using MF. The 1D MK-II is a lot better than the 10D, but there are limitations simply due to the way in which Canon have designed the AF system.