Oof shots

One group of shots were all oof. My daughter was running toward me with strong sun backlighting. The shutter speed was 1/800. All of the shots were soft or oof for one or two groups of high speed shots. I was in ai servo high speed shutter. I'm just trying to understand how it works.

I've seen the same thing with very strongly backlit photos. It seems beside trashing contrast on the subject, strong backlight can confuse the AF, too. Longer lenses and tighter framing help, but it seems unpredictable to me. Oh, that was on 60D and 6D. I haven't tried it with my 70D, yet.

This may make sense. I am also wondering if I didn't kick focus on my daughter initially as she started running toward me, and then it just had a focus error all thought those frames because of a bad initially lock....

Frodge wrote in post #17722627
This may make sense. I am also wondering if I didn't kick focus on my daughter initially as she started running toward me, and then it just had a focus error all thought those frames because of a bad initially lock....

I believe the 60D will try to correct focus between shots in AI-Servo, especially if nothing is in focus. I've had it lose focus for a frame or two, then come back. I can't test. I've sold my 60D.

some lenses just can't keep up with something coming directly at you...what lens were you using?

DreDaze wrote in post #17722637
some lenses just can't keep up with something coming directly at you...what lens were you using?

The slowest focusing lens I've ever had was the 18-135 IS. It could keep up with a dog on a dead run straight at me, on a T1i. Humans just don't move that fast.

Some lenses are faster, 2.8 lenses can be more accurate. There's also custom functions on the 60D for selecting AF points:

AF Selection

In AI servo, the camera will first start with the selected AF point and then find movement coming from there. The easiest way of focusing a moving subject is to press the focus as soon as your subject is on the center focus (I always BBF), and then continue moving the camera to keep the subject around that point.

AI Servo

AI Servo and BBF

Shot with a T3i and 40stm

There were also other situations just like that today where all the frames were perfect or near perfect. Just one or two runs like this. It is of course possible that I had moved the focus point. Hard to say.

Yeah, when I shoot my friends kids, I find my camera tracks just fine.....it's just that they like to keep coming right up to the camera lens (and stay too close)

davesrose wrote in post #17722658
Some lenses are faster, 2.8 lenses can be more accurate. There's also custom functions on the 60D for selecting AF points:

AF Selection

In AI servo, the camera will first start with the selected AF point and then find movement coming from there. The easiest way of focusing a moving subject is to press the focus as soon as your subject is on the center focus (I always BBF), and then continue moving the camera to keep the subject around that point.

AI Servo

AI Servo and BBF

The 60D allows you to pick a starting AF point while in AI-Servo? I had mine 5 years and never noticed that. I always used the center.

Not sure about the 60D....assume so (you have to be in individual point selection and not auto point selection mode...and assigning some custom buttons make the AF selection quick). With my 5D3, I can even be in auto AF point selection mode and emphasize a point. I can first select a point that I think the subject will be in, and then as I hit the focus button, the camera will start with it and then start tracking and selecting the neighboring points.

My 70D works like your 5D3 in AI-Servo. I can select any point to start with. Camera will use all other points to maintain tracking. The 60D didn't do that; you had to start with the center point in AI-Servo, I think. Frodge?

It looks like you select focus points in a similar manner as the 5D/7D/70D series....hitting the AF point selection button and then selecting which point to use. So the 60D would ignore that in AI-Servo and go to center point? Wasn't aware any Canon did that.

davesrose wrote in post #17722683
It looks like you select focus points in a similar manner as the 5D/7D/70D series....hitting the AF point selection button and then selecting which point to use. So the 60D would ignore that in AI-Servo and go to center point? Wasn't aware any Canon did that.

I believe my 450D and 500D worked the same way. AI-Servo keys to center point only. You can select ALL POINTS or any one point. You can't use ALL POINTS and pick a starting point. Maybe just the XXXD models and the 60D?