Improving AI-Servo accuracy for street shots?

I seem to be getting very low success rates with AI Servo (with auto AF but tried center as well). It is better with my 70-200mm F4 IS (about 50/50) and 135mm F2 (25% of the time).

These are for street shots.

Any tips from my fellow PotNers? Here are some samples to describe my inaccuracy.

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I would stick on centre point

Auto AF with so much going on in the frame is not going to work out very well. Pick a point and I would imagine that your keeper rate should increase dramatically.

I actually switched from center AF to auto AF recently to see if I can improve accuracy. Doesn't seem to be working (obviously). I was just wondering if there anything other than AF points or am I expecting too much for more than a 50/50 rate.

For the 60D, if you can adjust the bias towards accuracy(opposed to acquisition speed).

If that doesn't work, buy a 17-55

And then get a 7D.

You know you want one.




How do you like the 135/2 on the 60D?

Don't use Auto AF selection; the camera will frequently choose something other than what you want, as it appears to have done in both of these shots.

For the most part, I'd stick with single AF point and One Shot unless you really are spying on someone

If you want accurate AI servo, you need a better camera.

1-series, or maybe the new 5D3.

Or just about any pro-level Nikon body (D300 and above).

Even the T1i can grab great shots in Servo; so that's more than a bit of hyperbole there And, comparing an existing camera to one that isn't even announced yet...

Snydremark wrote in post #13995390
Even the T1i can grab great shots in Servo; so that's more than a bit of hyperbole there And, comparing an existing camera to one that isn't even announced yet...

Not if you need to track with off-centre points for composition reasons, or if you're shooting with ultra-thin DOF...

And, of course, you can grab great shots in servo with anything - but we're trying to maximise keepers here.

And you maximize keepers by getting better at using the camera; not by buying new gear.

OP: Besides Servo, how else do you have the camera set up?

Snydremark wrote in post #13995438
And you maximize keepers by getting better at using the camera; not by buying new gear.

OP: Besides Servo, how else do you have the camera set up?

AI servo speed and accuracy has nothing to do with skill. You're entirely reliant on the AF to acquire and keep focus - nothing you can do will make it any more or less accurate.

Even if you have no skill whatsoever, with a good AF system, your photos will be in focus. They may be compositionally crap, with blown highlights and shadows, but at least they'll be sharp where you wanted them to be.

Conversely, no matter how good you are, if your AF system can't keep up with your subject (due to subject speed, variable movement, lighting or contrast) you'll get blurry shots. Compositionally excellent and perfectly lit, maybe, but out of focus.

Shadowblade wrote in post #13995451
AI servo speed and accuracy has nothing to do with skill. You're entirely reliant on the AF to acquire and keep focus - nothing you can do will make it any more or less accurate.

I'd say having the skill to select the proper AF point and keep it on the subject would do a lot more to improve the image than a new piece of (improperly used) gear.

We're talking about street photography here, not fast-moving sports. The xxD bodies' AF system, if set up and used properly, is more than adequate for the OP's needs.

Veemac wrote in post #13995462
I'd say having the skill to select the proper AF point and keep it on the subject would do a lot more to improve the image than a new piece of (improperly used) gear.

We're talking about street photography here, not fast-moving sports. The xxD bodies' AF system, if set up and used properly, is more than adequate for the OP's needs.

Can't anyone keep an AF point on target? It's not the most difficult thing in the world...

And selecting the proper AF point is more to do with composition than focus. If the AF system is adequate, it shouldn't matter which AF point you choose - whatever you point it at should be in focus.

With center point manual selection and your USM lenses, you should be able to catch focus very quickly in One Shot. Give that a go and see if your keeper rate goes up.. Personally, I don't think it is necessary to use AI Servo when shooting on the street.

I'm assuming you've tried the AF Auto Expansion feature? The center point is highlighted with 3-4 smaller boxes surrounding it.