What focus mode do you use?

[te1221]

I was reading up on fred miranda forums that a lot of people are using AI Servo for weddings to capture the people in motion. I was thinking about trying to leave my XT in AI focus so it will switch back and forth. Currently I use one shot. I am aware it probably uses more battery to keep it in AI focus, but would it be a better idea when capturing objects that are moving slowly as well?

[cdifoto]

I was reading up on fred miranda forums that a lot of people are using AI Servo for weddings to capture the people in motion. I was thinking about trying to leave my XT in AI focus so it will switch back and forth. Currently I use one shot. I am aware it probably uses more battery to keep it in AI focus, but would it be a better idea when capturing objects that are moving slowly as well?


IMO people don't move fast enough for AI Servo to work well. AI Focus is ok but it's also unreliable from my own experience. One shot with regular half-pressing of the shutter release seems to be best, again IMO.

[te1221]

The main reason I'm asking is because I notice my 17-40 hits dead on with focus a lot more consistently than my 50 F1.4. I'm using both in low light with an external flash. When it does hit, it is tack sharp. I'd probably say I have like a 60-70% hit rate with the 1.4 whereas with the 17-40 I cant say I've had shots that were completely out of focus.

I'm wondering if it's my XT, or maybe I need to send my 50 in for calibration.

[Bluedog]

My 30D stays in single shot center focus point 95% of the time.

[24Peter]

My 30D stays in single shot center focus point 95% of the time.
My XT stays in single shot focus 100% of the time and portrait point (extreme top/right) 90% of the time when shooting people.

[aparmley]

The main reason I'm asking is because I notice my 17-40 hits dead on with focus a lot more consistently than my 50 F1.4. I'm using both in low light with an external flash. When it does hit, it is tack sharp. I'd probably say I have like a 60-70% hit rate with the 1.4 whereas with the 17-40 I cant say I've had shots that were completely out of focus.

I'm wondering if it's my XT, or maybe I need to send my 50 in for calibration.

Your 50 may need calibration - do you shoot it at F4 when comparing to the 17-40?

Single shot focus for me - I've found AI servo to be about as accurate as me focusing manual when it comes to a moving object and it drains the battery real fast.

I use every focus point. I've noticed with my XT that anything but the center point is real iffy.

[cdifoto]

I've found AI servo to be about as accurate as me focusing manual when it comes to a moving object and it drains the battery real fast.

I use every focus point. I've noticed with my XT that anything but the center point is real iffy.

My XT + 70-200 did really well with AI Servo at the soccer game Thursday evening. I had about a 95% success rate, including shots that were so far across the field that the players weren't much bigger than a focus point. That was plenty with of light and using the center point most of the time though.

Hmmm...I think I'm gonna hafta activate all my points and see how well that does...players isolated on the field shouldn't pose a problem with incorrect point being chosen. At least I wouldn't think so...

[aparmley]

I use every focus point. I've noticed with my XT that anything but the center point is real iffy.

please read the bold comment above like so - I use every focus point - but only one at a time - I select my focus point - if my subject is off center I move my focus point - I don't focus recompose.

[cdifoto]

please read the bold comment above like so - I use every focus point - but only one at a time - I select my focus point - if my subject is off center I move my focus point - I don't focus recompose.

I knew what you meant Andy. I'm just saying I didn't seem to have trouble with AI Servo at all on Thursday. Matter of fact, I had little trouble with the 24-70 mounted on Saturday even though it was relatively dark. I didn't have as high of a success rate, but only one or 2 of the shots were totally out of wack some others were slight misses as you might expect in a lowlight situation.

My comment about using all focus points at once was just kind of an "out loud" thought, not really related to what you said. :o

[aparmley]

I knew what you meant Andy. I'm just saying I didn't seem to have trouble with AI Servo at all on Thursday. Matter of fact, I had little trouble with the 24-70 mounted on Saturday even though it was relatively dark. I didn't have as high of a success rate, but only one or 2 of the shots were totally out of wack some others were slight misses as you might expect in a lowlight situation.

My comment about using all focus points at once was just kind of an "out loud" thought, not really related to what you said. :o

I wasn't sure if you misread my comment - but it made me think how easy it might be for others to think that perhaps I use all focus points active, which cleary isn't the case.

[cdifoto]

I wasn't sure if you misread my comment - but it made me think how easy it might be for others to think that perhaps I use all focus points active, which cleary isn't the case.

True enough. We know what we're talking about...sometimes...but perhaps a lot of lurkers do not. :eek:


But on another note...I was using the black XT both times. The silver one is/was normally my workhorse and seemed to have more focus problems. I sent it back in yet again to get the shutter button fixed (I lost my half-press sensitivity) but also included a note mentioning the focus issues and if they could check it once more. It's a little out of warranty but hopefully Canon will be good natured like the rep said and fix it within the "grace period".

[te1221]

Your 50 may need calibration - do you shoot it at F4 when comparing to the 17-40?

Single shot focus for me - I've found AI servo to be about as accurate as me focusing manual when it comes to a moving object and it drains the battery real fast.

I use every focus point. I've noticed with my XT that anything but the center point is real iffy.

Yes both were shot at F4 actually, so the 50 was stopped down while the 17-40 was wide open.

[te1221]

Actually I've done some controlled testing and I think the problem is coming more from user error because i'm not used to shooting at such a low tolerance for shallow depth of field. It's just something I need to practice with :)