Autofocus and airshows

Anders I personally would reccomend removing the AF from the shutter button when using BBF. You can then be sure of exactly what the AF will do in any situation. With AIServoAF selected you can use it just like OneShotAF by pressing and releasing the focus button. If you still have AF on the shutter button though the camera will AF again as you press through to release the shot. Also if you are holding the shutter at half between bursts in AIServo then you will be overiding the BBF if you have not separated AF and AE/Shutter.

Alan

@persson850 and everyone, thanks very much for the great answers! I knew what panning is and do pan a moving subject. I zoom out a bit to locate, then zoom in and pan before/after shooting. I was just using the incorrect drive mode and AF mode for my subject. My T1i has AI Servo and continuous shooting, plus either selecting only the center AF point or, with AI Servo, setting auto AF point selection, which starts with the center AF point while tracking, but if the subject moves off the center AF point the camera will switch to another AF point. Unfortunately, it does not have Back Button Focus. I'll have to practice holding the shutter release down halfway while panning.

"All knowledge is learning and therefore good". / D.A.R.Y.L.

At these distances, and having plenty of light, DOF should cover unless the planes are flying straight at or away from you. I would try a hyperfocal focus technique here, understanding that traditional DOF scales underestimate DOF you will see in the 2014 digital world.

BNOmnivore wrote in post #16665633
My T1i ...Unfortunately, it does not have Back Button Focus. I'll have to practice holding the shutter release down halfway while panning.

I believe even my old XT was capable of BBF. I know that my T2i is capable. Look in the custom function menu.

does BBF work with AI Focus, or would need to keep button pressed if tracking a moving subject?

The T1i does have back button focus; you can assign it to the * button. Just go into the custom function menu, custom function 10, check out settings 1-3. I found that on the online manual here: http://www.fhs.cuni.cz …ka/dokumenty/eo​s-500D.pdf

No excuses now. We want to see your best pics from the next airshow

Cheers,
Eros

birderman wrote in post #16667561
does BBF work with AI Focus, or would need to keep button pressed if tracking a moving subject?

AIFocus is the least responsive choice, as all it does is to try to figure out whether to switch you to One-Shot or AIServo. The popular wisdom here is to recommend not using it (I agree).

After extensive testing in my 60D I decided to use BBF/AIServo?No Shutter button AF exclusively. I have no evidence of detrimental behavior in nearly two years.

Does the sole use of BBF make focusing any faster(in camera focus time rather than combined -focus exposure etc)?


P.

Just to explain myself a little better - say you are just using the BBF with focusing disabled on the shutter button, then at the moment you press the shutter only then does the exposure take affect, is will this produce faster focusing over the same situation where just using the shutter button for everything?


P.

Keyan wrote in post #16662732
Nice shot, btw, I have yet to see a Raptor.

yes, the F-22 Raptor has had some problems then 'sequestration' cancelled most of the military air shows. Hopefully this year will be better

Performancewise, AF works the same regardless of which button you press. But starting AF prior to actually taking the picture makes the response faster. But it doesn't matter which button you use to start AF.

watt100 wrote in post #16670302
yes, the F-22 Raptor has had some problems then 'sequestration' cancelled most of the military air shows. Hopefully this year will be better

Yeah, sad. Actually the sequestration caused my local airshow to cancel entirely last year...and now they have decided to not continue it at all. I am super-bummed about it.

MakisM1 wrote in post #16667657
AIFocus is the least responsive choice, as all it does is to try to figure out whether to switch you to One-Shot or AIServo. The popular wisdom here is to recommend not using it (I agree).

After extensive testing in my 60D I decided to use BBF/AIServo?No Shutter button AF exclusively. I have no evidence of detrimental behavior in nearly two years.

Oops typo gremlins sneaking in, I meant to say AI Servo, anyhow if AI Servo is selected with BBF does one need to keep the button pressed to maintain focus on a moving object ?

BNOmnivore wrote in post #16665633
@persson850 and everyone, thanks very much for the great answers! I knew what panning is and do pan a moving subject. I zoom out a bit to locate, then zoom in and pan before/after shooting. I was just using the incorrect drive mode and AF mode for my subject. My T1i has AI Servo and continuous shooting, plus either selecting only the center AF point or, with AI Servo, setting auto AF point selection, which starts with the center AF point while tracking, but if the subject moves off the center AF point the camera will switch to another AF point. Unfortunately, it does not have Back Button Focus. I'll have to practice holding the shutter release down halfway while panning.

"All knowledge is learning and therefore good". / D.A.R.Y.L.

Look in the custom functions; it's there, and I've been using it on my T1i for the last year or so.

birderman wrote in post #16681095
Oops typo gremlins sneaking in, I meant to say AI Servo, anyhow if AI Servo is selected with BBF does one need to keep the button pressed to maintain focus on a moving object ?

Yes. You can keep the back button pressed while you click the shutter too, so it will continue to try to focus between shots.