Bracket Exposures Using Back Button Focus
I have my Nikon D7500 set up for back button focus in continuous release mode. I plan to do some exposure bracketing (for HDR purposes in challenging lighting conditions) in landscape photography using the self-timer delay to avoid camera movement. My understanding is that holding down the back focus button results in continuous focus tracking unless the button is released which results in focus being fixed/frozen (until/unless the button is pushed again). I can then use the self-timer to do multiple images in the bracket at the fixed focus.
Under this scenario, does it matter whether I have custom setting a1: AF-C Priority Selection set to release or focus? The Menu Guide has me confused with the following statement: "Regardless of the option selected, focus will not lock when AF-C is selected for autofocus mode. The camera will continue to adjust focus until the shutter is released.
Maybe I am confused but it seems to me that letting up on the back focus button after the lens focuses does lock the focus without regard to the a1: AF-C selection. Or is it preferable to just go ahead and select focus for custom setting a1 for some reason?
Thanks for any help.