sathca Loc: Narragansett Rhode Island

I was about to pose this question...... "I have a problem when in continuous auto focus mode. I use back button focus on my D750 and D610. If I move around to different subjects or if the subject is difficult to track the auto focus will freeze and not restart unless I release the back button and reapply. Sometimes I might have to do it several times. It seems I can cause it to happen by moving from close focus and then back out to a distant subject but that's not always the case. But since I've tried to make note of when it happens it seems to happen more often when the lens goes to it's minimum focus distance and I go back to something farther away. It does it on both cameras and with different lenses ( Nikon 200-500 and Tamron 150-600 G2 ). The D750 just came back from Nikon after being dropped and was supposedly returned to factory specs. Auto focus was said to have been adjusted." ..........But then I tried my old 80-200 2.8 and the problem never happened. So it's not the camera's, it's the lenses. The 5.6 ( Nikon ) and 6.3 ( Tamron ) maximum aperture doesn't provide enough light for optimum auto focus performance( I'm guessing ). But there's still a question here because I don't know if that should happen at all. I could understand if the lens hunted but didn't focus. But it just stops. I can point it at a bright light and it still won't attain focus unless I release and press the button again,sometimes several times. Is this common with these lenses or do I have a problem needing repair?

via the lens Loc: Northern California, near Yosemite NP

Use AF-C and release priority. BBAF is set once you hit it and then will not focus again until you hit it again, that is how it operates. It's a set and then set again type of thing, depending on your subject. Read your manual on the focus system and get the book by Mike Hagan on the Nikon Autofocus System.

Bill_de Loc: US

In Nikkor lenses it is sometimes an indication of an AF-s motor is on it's way out.

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chase4 Loc: Punta Corona, California

Our member Steve Perry has some great videos on Nikon autofocus uses/settings. Check this link out:

https://www.youtube.com/watch?v=_N_bzhJAKms&t=16s

Good Shooting, chase

sathca Loc: Narragansett Rhode Island

I have it set to AF-C and release priority. It is not set once you hit it, it's set if you take your finger off the button. As long as you're pressing the button it should adjust to whatever is in front of the sensor. It is supposed to focus "continuously". As I said it works with the 80-200 2.8 and it works until it doesn't with the other lenses. I have the book by Mike Hagan and the one by Steve Perry.

chase4 Loc: Punta Corona, California

I have a Nikon D610 and here's a copy of what Nikon says at nikonusa.com about the D610:

"Remarkable AF performance with compatibility up to f/8 One of the keys to capturing razor-sharp images is a fast, precise autofocus system, and the D610 has one of the best. 39 tightly packed focus points with wide-area AF coverage offer endless compositional possibilities. Nine cross-type sensors in the center offer superior accuracy even when light and contrast are scarce. Seven center focus points work all the way down to f/8 for extended AF functionality with teleconverters and long-reach lenses. Switch between 9, 21 or 39 point AF, allowing for compositional freedom. D610's Scene Recognition System's subject identification and tracking information means enhanced performance by 3D Tracking and Auto Area AF. When shooting photos or HD video in Live View, Nikon’s responsive contrast-detect AF activates for accurate fulltime autofocusing."

I don't use BBF but my D610 can focus at f/8 and >. chase

rgrenaderphoto Loc: Hollywood, CA

Continuous focus is the key.

rdubreuil Loc: Dummer, NH USA

jerryc41 Loc: Catskill Mts of NY

I have the same camera, but I've never experienced that. Interesting situation.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Sorry, I have always used the correct default release button (you know, the one on top of the camera) with the D500 and the 200-500 mm lens. Never a problem, never a hesitation, always works great. And, I always get the shot (never missed yet). Can you tell I am not a proponent of rear camera shutter release.

jerryc41 Loc: Catskill Mts of NY

You mean focus?

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

I mean I push the shutter release button on top of the camera half way and it focuses, if I am in continuous auto focus the camera stays in focus and when I want to shoot I press the button all the way down. Just like the manual tells me to.

Bill_de Loc: US

You are correct.

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dannac Loc: 60 miles SW of New Orleans

Just to test ... you could try assigning back-button-focus to another button, to see if it makes a difference.

Rich1939 Loc: Pike County Penna.

Real handy for old coots that can't stand still or have the shakes