Sharpness of a still shot using back button focus

[DanK]

I find this a bit confusing because the starting question and thread mix together a number of very different things: single shot vs a tracking mode, focus and recompose, back button vs. shutter button, moving subjects vs. stationary subjects, lighting, and maybe more. The fact that I use Canon may make this even a bit more confusing because the terminology is different.

Nonetheless, i think the only way to get clarity is to separate these things. assuming Nikon works like Canon:

-- the back button, like the front button, is simply binary: on or off. The two cause exactly the same response by the camera.

--at least on Canon cameras, there is no need for a "focus lock" option: when you take your thumb off the back button, AF stops. That is the primary reason I use BBF for 95% of my shooting. I want to control when AF is on and when it's off, and I want that separated from my decision about when to trip the shutter. I do often do use shutter control of AF when I'm tracking something moving--say, a runner in a marathon--because under those circumstances, I don't want to stop AF earlier than tripping the shutter, and it's simply easier to leave AF on the shutter button.

--re the accuracy of continuous vs. one-shot focusing: I have often wondered about that but didn't have an answer. My hunch was that single-shot was more accurate for static subjects, at least if operator behavior is included in the consideration, because on Canons, only single-shot AF provides focus confirmation. This thread has taught me that this hunch was correct.

[Stagecoach]

--re the accuracy of continuous vs. one-shot focusing: I have often wondered about that but didn't have an answer. My hunch was that single-shot was more accurate for static subjects, at least if operator behavior is included in the consideration, because on Canons, only single-shot AF provides focus confirmation. This thread has taught me that this hunch was correct.

On my Nikons, 'focus confirmation' (a small green light in the viewfinder) is there for both AF-S (single) and AF-C (continuous).

Additionally, in both AF-S and AF-C modes you can select whether the shutter will activate only when the camera registers it's in focus or not.

With respect to your method described of shooting runners, on the Nikon I will use AF-C keeping the BBF pressed and fire away.

[DanK]

With respect to your method described of shooting runners, on the Nikon I will use AF-C keeping the BBF pressed and fire away.

My Canon will as well. However, since I want to keep the AF running, I find it simpler not to have to hold the BBF button down. However, if something is moving intermittently, I would use BBF.

[cauger61]

Hi Sanjib

I always perform AF tests under natural light. Of course if you are always going to be shooting under a specific light source (or more accurately....auto-focussing under a specific light source), then you would be better off calibrating under that source.

Yes very true. Thnx u very much.

[rpcrowe]

When I am shooting portraits with my Sony mirrorless cameras, I choose continuous AF and eye-AF... Even when both the subject and I am not moving to any great degree. The Continuous Eye AF will compensate for the slightest movement between the camera and the subject...

[mariah]

I do not think that there is anything as you mention that the clarity is locked or something. What you are using is not even for a stationary object shot lens. You are using a different lens and that is why you are facing difficulties getting the clarity out of a stationary object.

[pschlute]

I do not think that there is anything as you mention that the clarity is locked or something. What you are using is not even for a stationary object shot lens. You are using a different lens and that is why you are facing difficulties getting the clarity out of a stationary object.

I am afraid your online translator is not working. Your post makes no senses at all