Struggling with D7100

Started Feb 9, 2014 | Questions thread
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nfpotter Veteran Member • Posts: 4,080
Re: Possible

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...

Um, HUH?

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?

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

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

What you're not getting is that with the set-up and examples you're using, you HAVE NOT covered all your bases, to ensure that you're always getting the most accurate focus.  Mako did not suggest it IS a mirror adjustment needed, he simply pointed out yet another factor (thanks, Mako) that COULD come into play.

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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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