Back Button Focus: I was hoping you all could help me figure out why the back button focus will not work at times. I am shooting with a Nikon D850 with 85mm lens.In the middle of a...

SandraLovesPhotography

I was hoping you all could help me figure out why the back button focus will not work at times. I am shooting with a Nikon D850 with 85mm lens.In the middle of a shoot, it just won't focus at all. Do you all prefer the back button focus?

Bill_de Loc: US

Make sure that when you set up for BBF that you disabled the shutter button from focusing.

I personally don't use BBF, but I am in the minority.

--

Old Timer Loc: Greenfield, In.

I am not a Nikon shooter but I would suspect that your metering selection, such as center, evaluate, or Al servo could be the problem. Read your manual and it should explain the different types of metering. I had some problems with my Canon till I read the field manual and the explanations.

Dan R Loc: Way Way Way Upstate NY

I hate to ask this, but could you be too close to your subject for the lens?

Bill_de Loc: US

Old Timer wrote:

I am not a Nikon shooter but I would suspect that your metering selection, such as center, evaluate, or Al servo could be the problem. Read your manual and it should explain the different types of metering. I had some problems with my Canon till I read the field manual and the explanations.

I don't know about Canon, but in Nikon I don't believe metering mode has anything to do with focus.

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MadMikeOne Loc: So. NJ Shore - a bit west of Atlantic City

SandraLovesPhotography wrote:

I was hoping you all could help me figure out why the back button focus will not work at times. I am shooting with a Nikon D850 with 85mm lens.In the middle of a shoot, it just won't focus at all. Do you all prefer the back button focus?

Do you have your Autofocus Mode set to AF-C?

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

SandraLovesPhotography wrote:

I was hoping you all could help me figure out why the back button focus will not work at times. I am shooting with a Nikon D850 with 85mm lens.In the middle of a shoot, it just won't focus at all. Do you all prefer the back button focus?

I don't have an answer for your BBF not working, but I do use BBF on my Df and have not had a problem.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

As above. My Canon 7d 1/2 press shutter relasse totally screws up BFF that's why I shut it off. As an aside--As a totally manual filmshooter. I was an trained to slowly press the shutter. When I first used that 7 d I pressed the shutter button very slowly. I was surprised when 8 shots were made before m y hand realeased that button

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

As above. My Canon 7d 1/2 press shutter relasse totally screws up BFF that's why I shut it off. As an aside--As a totally manual filmshooter. I was an trained to slowly press the shutter. When I first used that 7 d I pressed the shutter button very slowly. I was surprised when 8 shots were made before m y hand realeased that button

toxdoc42

It happens to me occasionally, the focus dots disappear, I just depress the shutter a little and the focus dots return. It is annoying but not a fatal problem.

User ID

`

I don't use your model of camera, but I
always use BBAF, and here are 2 things
that make my AF button act "dead":

1. Focus targeting mark is not covering
anything focusable.

2. How I position my face against the
eyepiece.

Just food for thought.

`

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

User ID wrote:

`

I don't use your model of camera, but I
always use BBAF, and here are 2 things
that make my AF button act "dead":

1. Focus targeting mark is not covering
anything focusable.

2. How I position my face against the
eyepiece.

Just food for thought.

`

I don't understand how you position your face against the eyepiece can affect BBF.

User ID

Mac wrote:

I don't understand how you position your
face against the eyepiece can affect BBF.

If I have the quick menu active on the
monitor, there's a proximity sensor that
shuts it off and returns the camera to
normal picture taking activities. I have
two different brands with such a sensor.

`

KenBlackwell Loc: Killeen, Texas

Check the focus lock switch. I have inadvertently turned it on during a shoot. Thought I had a serious problem.

SusanFromVermont Loc: Southwest corner of Vermont

SandraLovesPhotography wrote:

I was hoping you all could help me figure out why the back button focus will not work at times. I am shooting with a Nikon D850 with 85mm lens.In the middle of a shoot, it just won't focus at all. Do you all prefer the back button focus?

I use bbf on my D810 all the time. Love it. The manual does not specifically address how to set it up, which can make it difficult to know if you have done it properly. First, you have to assign focus to the button. Then you have to remove the shutter-release button's ability to focus. Each of those are discussed in the manual - look in the section devoted to setting up.

If you have gone through the required steps, then consider it may be a problem with the camera. For that possibility, Nikon support would be the place to go for getting answers.