D7200 with 35mm DX 1.8 struggling to focus

Joined
Mar 25, 2011
Messages
2,313
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London
Today was a very very grey and miserable day in London weatherwise.
Nothing remarkable to shoot at but I decided to have a go anyway.
Most of the time the combo D7200-38mmDX was not able to AF.
Here are a few examples of very difficult AF.
Nothing remarkable with any of these shots but after a while I decided to shoot manual focus.

I know I am not giving a lot of info but under what conditions should I expect the AF to fail?


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Joined
Jul 8, 2019
Messages
391
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SF Bay Area, California, USA
AF checklist
  • Does the lens AF in a controlled setting?
  • What AF mode is the camera in? Area or closest subject takes focus selection out of your hands, which is why I do not use it, does not work for me.
  • WHERE is the active AF point in the image?
  • Is the active AF point on something that has enough contrast for the AF mechanism to focus on?
#1 is a bit odd, as it seems to me that only an area on the left middle is in focus. Kind of like you were shooting through a mask.
 
Joined
Mar 25, 2011
Messages
2,313
Location
London
Thanks for the checklist.
I had cleaned the contacts but will clean them again.
I reset the AF to single point center and it is working much better.
It must have been on an area setting with face tracking on or an auto mode with 3D.
I had been shooting with my Sony Alpha 5000 the days before and keep on noticing how superior in the situations I am in the Sony AF is to Nikon’s.
I will keep my D7200 on single point AF for now.
Also re reading the manual quite a few of the scenes were grey on grey or buildings with lines which Nikon states are “AF Fail”’situations.
I need to practice more.
Thanks for the tips.
 
Joined
Jul 8, 2019
Messages
391
Location
SF Bay Area, California, USA
It has been a while since I read the manual. I should go look at the AF fail section.

Usually I have no problem with the AF.
When I do, it is usually 'pilot error' of various sorts.
Two very common ones for me are:
  • Quickly changing from subject A to subject B. When I press the shutter on subject B, the lens is still changing focus from subject A, so subject B is OOF. The 2nd shot in the burst is usually in focus, as the lens has finally focused on subject by the 2nd frame. Unfortunately, it is the OOF frame 1 that I usually want.
  • Similar movement as above, but in the shift, I overshoot the subject, and the AF point is on the background when I press the shutter.
My first instance of AF confusion was when I got my first dSLR, a Nikon D70.
I set it on Auto, then shot at a family party. Over half the pics were OOF.
On studying the pics, and RTFM, I figured out that in Auto mode, the camera uses "closest subject" logic to AF.
And that was the problem, on all the OOF pics, the camera focused on something that was between the subject and me.
On the dinner table group pic, it focused on the food dishes on the table, not the guests on the other side of the table. :mad:
I NEVER again used Auto mode.

My yearbook students would use the camera in zone/area focus mode, then complain that their subject was OOF.
The first time it confused me, until I figured out how to determine what AF mode was used and what the camera focused on. Then the problem was clear.
Zone AF on the Canon uses "closest subject" logic. ah ha
After that, even though it is more difficult for them, I told them to NOT use zone AF. Because MANY times their subject is farther away than other students in the frame, and the zone focus will focus on the closer student, not their subject.
But kids being kids, most of them take the easy option and use "sports scene" mode, which uses zone AF.

With both Auto mode and scene modes people have to understand HOW the AF works, or they run right into these problems, without knowing why. Then they blame the camera.

I occasionally use face recognition AF. But usually it is more problem than it is worth, for me.
In group/party environments, the face recognition will grab faces on the side or WAY behind my subjects. And I have not been able to figure out how to limit or redirect the face AF. So I stopped using it.
In a situation where there is ONLY my subjects in the frame, then it works.
 
Joined
Mar 25, 2011
Messages
2,313
Location
London
It has been a while since I read the manual. I should go look at the AF fail section.

Usually I have no problem with the AF.
When I do, it is usually 'pilot error' of various sorts.
Two very common ones for me are:
  • Quickly changing from subject A to subject B. When I press the shutter on subject B, the lens is still changing focus from subject A, so subject B is OOF. The 2nd shot in the burst is usually in focus, as the lens has finally focused on subject by the 2nd frame. Unfortunately, it is the OOF frame 1 that I usually want.
  • Similar movement as above, but in the shift, I overshoot the subject, and the AF point is on the background when I press the shutter.
My first instance of AF confusion was when I got my first dSLR, a Nikon D70.
I set it on Auto, then shot at a family party. Over half the pics were OOF.
On studying the pics, and RTFM, I figured out that in Auto mode, the camera uses "closest subject" logic to AF.
And that was the problem, on all the OOF pics, the camera focused on something that was between the subject and me.
On the dinner table group pic, it focused on the food dishes on the table, not the guests on the other side of the table. :mad:
I NEVER again used Auto mode.

My yearbook students would use the camera in zone/area focus mode, then complain that their subject was OOF.
The first time it confused me, until I figured out how to determine what AF mode was used and what the camera focused on. Then the problem was clear.
Zone AF on the Canon uses "closest subject" logic. ah ha
After that, even though it is more difficult for them, I told them to NOT use zone AF. Because MANY times their subject is farther away than other students in the frame, and the zone focus will focus on the closer student, not their subject.
But kids being kids, most of them take the easy option and use "sports scene" mode, which uses zone AF.

With both Auto mode and scene modes people have to understand HOW the AF works, or they run right into these problems, without knowing why. Then they blame the camera.

I occasionally use face recognition AF. But usually it is more problem than it is worth, for me.
In group/party environments, the face recognition will grab faces on the side or WAY behind my subjects. And I have not been able to figure out how to limit or redirect the face AF. So I stopped using it.
In a situation where there is ONLY my subjects in the frame, then it works.
I find that face focus is a lot smarter on my iPhone and my Sony A5000 than my D7200.
I am going back to my previous settings of single point AF which I set in the center.
That works for me.
I must have set the AF to some smart mode and forgot about it. Bad idea.
 
Last edited:
Joined
Jul 8, 2019
Messages
391
Location
SF Bay Area, California, USA
I find that face focus is a lot smarter on my iPhone and my Sony A5000 thank my D7200.
I am going back to my previous settings of single point AF which I set in the center.
That works for me.
I must have set the AF to some smart mode and forgot about it. Bad idea.
After I get back from a shoot, I TRY, to reset the camera back to what I consider my "standard" configuration, to prevent confusion the next time out.
Does not always work. Sometimes I miss resetting one change, and it bites me the next time out. This usually happens when I make a configuration change to something that I rarely change.
 
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