Shuuter doesn't release in my D750 using back button focus with AF-ON

hjensun

New member
Shuuter doesn't release using back button focus with AF-ON

I just got my new D750 from Adroma, and immediately set it up using back button focus with AF-ON. One thing I have noticed that it behaves differently with my D7100 is when it is used in AF-S/Single point focus mode, if I press the back AE-L/AF-L button to lock focus, let my thumb go off and recompose my picture, then occasionally I am not able to fire shots successfully, the shutter simply doesn't release all the time. This only happens in single point mode, if I change it to auto or group area mode, then the shutter can always release successfully after recomposition.

My other D7100 has the same settings, but I can always fire shots successfully without experiencing any shutter release problem. I am wondering if anyone has the same experience or I have a defective D750. Thanks for your help!

Eric
 
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Bikerbrent

Senior Member
Welcome aboard. Enjoy the ride.
We look forward to seeing more posts and samples of your work.

I am sure a D750 user will be along shortly to help you out.
 

Texas

Senior Member
One of the menu items is for "S" - it allows the choice of release / focus
Perhaps that option is set for the focus.

There's another menu option for "C" with the same choices, maybe it is set for release

This is a quick wild guess, have not tested my D750's behavior yet
 

hjensun

New member
One of the menu items is for "S" - it allows the choice of release / focus
Perhaps that option is set for the focus.

There's another menu option for "C" with the same choices, maybe it is set for release

This is a quick wild guess, have not tested my D750's behavior yet

Yes, my D750 menu a2 (AF-S priority selection) is currently set as "Focus", and I understand it means the shutter won't release unless it got focus lock. The problem is after I pressed and released my thumb from the AF-ON button, I assume the focus should already be locked after the beep, so I should be able to press my shutter and fire the shot after I recomposed my picture. If I changed the a2 setting to "Release, then yes the shutter will always be released, but you won't hear the beep. As I said, this is not happening when you are using auto or group area focus with AF-S.

Eric
 

nickt

Senior Member
Your shutter is not firing because your camera is not seeing focus anymore when you recompose. This is what Texas mentioned above.
Also, the textbook bbf technique is to use af-c and release priority. You are missing out on the full benefit of the technique using af-s and you are likely at the default of focus priority. The camera may not fire if you recompose with those settings.

On the d7100 and d7200, the camera (oddly) overrides the a1 and a2 menu priority settings and you get release priority no matter what when you program the back button for af-on. So you didn't have to think about it on your d7100. Not sure what the d750 does but it probably sticks with the a1 and a2 menu settings. In any case, set af-c servo and also set menu a1 to release priority and you will be good to go for the full technique including focus/recompose.

If you must use af-s with bbf for some reason, then you will have to set menu a2 to release priority. The reason to use af-c is because in effect it gives you both servo modes. That is the beauty of the technique. Hold the button down and you get continuous focus. Release the button and you get a simulated af-s mode where you can recompose or pre-focus on a location.
 

nickt

Senior Member
Yes, my D750 menu a2 (AF-S priority selection) is currently set as "Focus", and I understand it means the shutter won't release unless it got focus lock. The problem is after I pressed and released my thumb from the AF-ON button, I assume the focus should already be locked after the beep, so I should be able to press my shutter and fire the shot after I recomposed my picture. If I changed the a2 setting to "Release, then yes the shutter will always be released, but you won't hear the beep. As I said, this is not happening when you are using auto or group area focus with AF-S.

Eric
No to the first part. It will not remember that focus locked. In the multi point modes, a different point is likely seeing focus and satisfying the camera to allow firing.
As for the beep, you won't get it when the technique is properly used.
 

samanth

New member
Re: Shuuter doesn't release using back button focus with AF-ON

Hi Eric,

I have the same problem. Do you know if the Focus/recompose works only with Group AF-S on D750? Is it a defect in D750?

Thanks,
Samanth.
 
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Marcel

Happily retired
Staff member
Super Mod
I'm not certain because I don't have the D750. But I think you have to disable the focus with the shutter button in order for what you are trying to achieve to happen. If the shutter button focus function is still enable, it's trying to focus where the focus point is, and since you have recomposed, it might be on something that hasn't got enough contrast or it starts hunting to acquire focus.
Hope this helps.
 

samanth

New member
I'm not certain because I don't have the D750. But I think you have to disable the focus with the shutter button in order for what you are trying to achieve to happen. If the shutter button focus function is still enable, it's trying to focus where the focus point is, and since you have recomposed, it might be on something that hasn't got enough contrast or it starts hunting to acquire focus.
Hope this helps.

Thanks, but I have bbf enabled and the half press shutter focus is de-coupled.
 

nickt

Senior Member
Re: Shuuter doesn't release using back button focus with AF-ON

Hi Eric,

I have the same problem. Do you know if the Focus/recompose works only with Group AF-S on D750? Is it a defect in D750?

Thanks,
Samanth.

Af-s with shutter button will focus/recompose regardless of the focus area mode.
BUT... if you are using bbf with af-s, that is not the typical bbf setup and it will not work in the way the technique is supposed to work. I'll stop short of saying it is wrong to use af-s with bbf. There may be some reason someone wants to do it that way, but it defeats the purpose of why most people use the technique.

The typical bbf setup is using af-c with release priority (menu A1). The method of use is to hold down the back button for continuous focus. You can keep the back button depressed and track the subject, shooting as needed. Or you can hold the bb down and when you are happy with the focus, release the bb and recompose and shoot. This technique allows you to be in af-c mode but at any instant, release the button and recompose. It gives you instant access to a simulated af-s mode.

If you were to set up bbf with af-s focus priority, recomposing while not holding down the bb will likely not allow shutter release. You could probably continue to hold down the back button while recomposing and that would let you recompose via af-s but that defeats the purpose of the "bbf technique". You would simply be using af-s mode activated by the back button only. You don't get the benefit of full time af-c with instant access to a simulated af-s. That is what most users want to achieve when using the "bbf technique".
 

samanth

New member
I was able to change it by making AF-S to release priority. I had single point focus set to "focus priority". I had to change it to "release priority" in the AF menu.

Thanks,
Samanth.
 

zilla

Senior Member
I had this issue on my D750 that I just purchased. At first I overcame it by setting the shot up and if the shutter stalled I switched to manual. A couple of things come to mind. One, is the focus lock lever on?? Two; After researching this on the ol interweb I found that I needed to set other menu items to overcome this issue. Google D750 BBF and browse the videos.. I can't recall which vid but the answer to proper setup is out there..

As for BBF NickT hit it on the head. BBF is best in "C" mode.. FWIW I bought a PDF book on line that extensively discusses Nikon focus systems and how to use them.

I believe it is called "Secrets To the Nikon Auto Focus System"
 

chatkat

New member
I inherited a D750 and also have the same problem. Sometimes if I turn the cam on and off it will work. I made sure my D750 settings were the same as my trusty D7200 to rule out having a setting that might affect my ability to shoot. I too use back button focus and have autofocus set to "release". I've made sure my battery is charged as I've experienced other functions that don't work if the battery is low. I just used an eraser on the lens contact So, it'll be interesting to see if these are real fixes.
 

Skwaz

Senior Member
Re: Shuuter doesn't release using back button focus with AF-ON

C356F0AD-3A6E-4B41-BAE4-40F6D6DA8CBC.jpg
May help
 
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