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D7100 + 35mm 1.8 DX. Focusing problems - Fine tunning does not work.

d7100 focus issues focus fine tuning

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#1
guillermo_arp

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The problem is that the camera plus the 35mm Lens are not focusing properly, by that I mean that is focusing just tad in front of my subject.

 

Conditions of my tests
 

- D7100 + 35 1.8mm both bought new.

- Target at 3 feet (1 meter) away from the lens, high contrast lines at a 45°

- On a tripod, tripod did not move. 

- Lens at 1.8 for shallow DOF

- Autofocus set to AF-S, center point, on a timer to avoid motion blur (Speed was somewhere  1/320 but just to be sure).

 

Tests:

 

1. Focus fine tune set to OFF.

1.1 After 5 shots I noticed that the camera was focusing somewhere around 1 cm too close (0.3" inches).

2. Focus fine tune set to ON

2.2  +5... no changes

2.3  +10 no changes

2.4  +20 it gets a little bit better.

2.5 - 5 it changes a lot  for the worst, it focuses even more closely than before.

2.6 -20 WORST, it's focusing way way closer. 

2.7 Just for the kicks I change the default value to - 17 and it gets better. Still not spot on, but better. So it gets: Default value -17 and Saved value +20 and focus is ALMOST perfect. 

 

So I wonder, why can't I move the focus point forward (Away from the camera)?

 

I also noticed after a few more shots lowering the F value that the focus point actually moves away. At F/8 focus looks perfect given the increased DOF, but it is actually about half an inch off away from the lens.

 

Another thing, I don't know if related but, when Selecting AF-A - AUTO, the camera has a tendency to "prefer" the left sensors on normal basis.. But for example if I shoot a blank wall with detail on the RIGHT it has no problem selecting the RIGHT sensors.

 

I'll appreciate any help I can get. I'm going PRO, can't afford new equipment at the moment and it's a real pain to take portraits out of focus.



#2
Merco_61

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Could you post one of your test shots? It is much easier to help if we see what you do.



#3
Nikonite

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For what it's worth I have that exact setup. The D7100 and 35mm 1.8 I mean. No problems here.







Also tagged with one or more of these keywords: d7100, focus issues, focus fine tuning