Focus/recompose with burst mode

Apologies because this is probably in the manual but I figure I'll get a quicker answer here

If I focus and recompose while using high speed burst mode, does the focus stay locked on the original focus point for all the shots in that burst?

Only if you remove the AF from the shutter button (using BBF). Otherwise, the moment you press the shutter button, the camera will re-focus

This has got to be one of easiest things that you could actually test yourself......

(hint...Markis is wrong)

John

If the camera is in One Shot focus mode, focus will not change once it's achieved, so long as you don't lift pressure off the shutter release. I'm not really sure where or why you might use One Shot along with a burst mode... But I'm sure someone can think of a time it might be useful. One Shot is for stationary subjects. Once activated, focusing does it's thing, then it stops, allowing you to recompose after you get Focus Confirmation.

If the camera is in AI Servo focus mode, it won't work. This mode is for moving subjects and constantly updates, never stops focusing and doesn't give Focus Confirmation. In fact, you can't focus/recompose at all in AI Servo unless you have switched focus from the shutter release to one of the back buttons (and stop focus action by lifting your thumb off the button).

Again, I don't know when or where you might be able to use BBF and recompose in AI Servo firing a burst. If tracking a moving subject, I can't think of a situation where you would want the AF to stop continuous updating. If you keep AF active and recompose, the AF will refocus onto whatever is under the AF point, after recomposing. In other words, recompose and you'll lose focus on the subject being tracked.

Rather than trying to use a focus and recompose method with a moving subject and shooting bursts, you might want to stick with a single, pre-selected AF point, frame the subject a little loosely and crop the image in post-production. Otherwise, you'll have to use one of the multi-point methods and hope the camera tracks the subject across different AF points properly. Or, you'll have to select a different AF point, that will give you the framing you want. Chances are you'll still need to do a little cropping, though.

amfoto1 wrote in post #14679467
I'm not really sure where or why you might use One Shot along with a burst mode... But I'm sure someone can think of a time it might be useful.

Well I was using it to focus on a large patch of poppies in the foreground, then recomposing/shooting in burst mode to catch a train going past quite fast in the background. I didn't need to focus on the train as the poppies were the main interest. I was shooting at f/11 so the train would be pretty much in focus anyway. I wasn't moving the camera... rather letting the train come into the shot and using high speed burst to make sure I got the train where I wanted it. Here's what I'm talking about:-

IMAGE LINK: http://www.flickr.com …/43829277@N07/7​515950504/

Vendee wrote in post #14679201
Apologies because this is probably in the manual but I figure I'll get a quicker answer here

If I focus and recompose while using high speed burst mode, does the focus stay locked on the original focus point for all the shots in that burst?

It depends how you set up the camera.

For the shot you took, you could set the camera up to use "back button focus" and then just press the BB once to obtain focus. Once focused, it will stay focused at that distance until the BB is pressed again.

On the 7d you can also alter the way in which focus is tracked between focus points/zones together with how quickly focus may change if objects pass across the focus plane.

Thus, depending upon settings, you could have obtained focus on the front of the train and, whilst holding the camera in the same position, have the camera track focus on the train across various point/zones.

I think selecting a lower AF point is the way to go here.

Although another way is use a tripod, focus, switch to Manual Focus mode, then burst....

Also, next time drag the shutter so the train blurs a little, that will contrast the pastoral flowers with the fast, industrial train.

PFDarkside wrote in post #14680123
I think selecting a lower AF point is the way to go here.

Possibly but for my style of shooting I usually use centre point focus and then recompose.

PFDarkside wrote in post #14680123
Also, next time drag the shutter so the train blurs a little, that will contrast the pastoral flowers with the fast, industrial train.

Did that years ago but still one of my favourite shots. I think I shot that with a Minolta A200 and I messed around with the saturation in Photoshop. It was only a couple of miles from the poppy shot:-

Byte size: ZERO | Content warning: NOT AN IMAGE

Well, setting up on a still target and the allowing some moving target to enter the frame as a secondary subject isn't really action photography and doesn't call for tracking the subject. Especially using a fairly small aperture.

I'd simply have used One Shot and focus/recompose. Could even have used manual focus, preset. Either way, pick something at the hyperfocal distance that covers the areas to be in focus, a point that would insure the foreground was in focus would probably dictate in this case, then take a burst as the train passes by.

amfoto1 wrote in post #14683283
Well, setting up on a still target and the allowing some moving target to enter the frame as a secondary subject isn't really action photography and doesn't call for tracking the subject. Especially using a fairly small aperture.

I'd simply have used One Shot and focus/recompose. Could even have used manual focus, preset. Either way, pick something at the hyperfocal distance that covers the areas to be in focus, a point that would insure the foreground was in focus would probably dictate in this case, then take a burst as the train passes by.

That's what I did. I focused on the foreground and took a burst when the train came into frame to make sure I had a selection of shots to pick from.

On the second train shot which I took over 5 years ago, I used a large aperture and focused at hyperfocal distance but because the shutter speed was 2/3 second to get motion blur, there was no point in using burst because the train would be out of frame by the third shot.