PIX 2015

Struggling with D7100

Started Feb 9, 2014 | Questions thread
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Mako2011 MOD
Forum ProPosts: 18,110
not always
In reply to chary zp, Feb 10, 2014

chary zp wrote:

Mako2011 wrote:

chary zp wrote:

Just to make it clear, by

" Um, yeah. 2 examples, each comparing at the same exact focal length and distance."

you mean that the exact focal lenght and distance of the scenario was wrong or good way to find out if D7100's untuned PDAF was ok or not, compared to the other bodies?

Comparing Liveview with PDAF at one focus distance (especially a close one) may not necessarily mean AF fine tune is called for but a good indication to check further. Comparing it to other bodies (especially in artificial light) can often lead to faulty conclusions.. but a fair way to "see if further investigation is called for.

It means that in artificial light the camera is faulty, because it doesn't PDAF properly, while "my friend's D90" works well...

For some reason...certain lens combinations and artificial light (usually lower than 5000K) can focus poor on the newer bodies and have no effect on older bodies. Don't know the physics or the whys of it.

This "um yeah" makes me feel you think it was wrong.

And how would you solve the wrong fine tune of the lenses differently than by fine tune?

I would use a lot more scientific approach to testing and evaluating than you are, and I'd VERY, VERY likely find that no fine tune was needed.

You mean in that those two examples where

D7100 fine tuned to 0 gave visibly poor results of PDAF compared to other bodies and fine-tuned D7100

was in your opinion actually right


the fine tuned sharper one

was actually wrong?

No, the fine tuned image was indeed sharper...but that does not necessarily mean the lens needs fine tuning or that that specific setting is the right one.

Because you'd come to conclusion that in fact "no fine tune was needed"? Really?

That can actually be the case. You may simply need a AF-Sub mirror adjustment.

How do I do that?

If you get different results in sunlight vs tungsten light with a particular lens (often affects one lens and not another)...often a AF-sub mirror adjustment by Nikon (only they can do that) will solve it. Getting them to do (or check for it) it is another matter

And what will happen to my 85/1,8G which works fine with fine tune 0?

Should still be fine

If I have my D7100 serviced to work with 18-105 perfectly, won't it scatter the other lenses which work fine now?

Not necessarily. Might just be a 18-105 issue and not a body issue. Also, seems to be a bit more sample variation with some of the less expensive models.

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My opinions are my own and not those of DPR or its administration. They carry no 'special' value (except to me and Lacie of course)

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My opinions are my own and not those of DPR or its administration. They carry no 'special' value (except to me and Lacie of course)

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