Hi

I got my camera back a week or so ago after a second trip to Nikon for the left focus problem. They had said to send back the camera, then they said to hold off while Japan looked at my pictures, then they said send it after 6 weeks or so of me waiting for the "analysis."

Today I spent some time shooting in a sculpture park, and upon looking at the images I have no idea what's happening with the focus. I shot in f 2.8 and 5.6 using left, center and right sensors, and sometimes on sensor was off and the other time it was the others.

I'm starting to go nuts with this. I have bad near and far vision and 5 different pro lenses and a Nikon service center with a verified track record of incompetence, and I have no idea any more whether its possible to own a working D800, and how to isolate my vision and equipment variables from the camera function.

Way I do see for sure is some shots using autofocus are clear, and some are not. This is across left, right and center sensors. Is there some way to actually measure focus accuracy objectively?

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From what I read online, PD AF cannot be precise all the time. I do not know what's the expected percentage of it being correct. I believe this is the reason to shoot multiple exposures for each sensor when testing for focus precision.

I do not know if your vision has anything to do with this - you are not focusing manually. Also, in my mind, if a camera misbehaves in the same sort with multiple lenses then only camera can be blamed for it - I would find it highly unlikely that multiple lenses would all experience same malfunction.

Alex
http://www.yermakov.net

The variation you are getting is a problem in coming up with any solution. That suggests your test conditions or technique may be an issue.

Take a look at this article over at LensRentals.com. The article is about a Canon lens, but I would expect to see similar variation for Nikon lenses.
http://www.lensrentals.com/blog/2012/11/canon-24-70-mk-ii-variation

My take would be that you need to work on technique until you get consistent results. Even the best photographers are going to miss focus. Not all subjects are good AF targets. And while AF today is the best ever, you have enough resolution in a D800 to see the slightest error.

I'm not saying you don't have a camera problem - just that variable results are most likely due to other factors than the camera.

Eric Bowles
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Thank you for your help.

Do any members here feel that FoCal software would help me zero in on camera function, and help me fine tune my lenses?

Is it worth the $100 for the pro version?

Thank you

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I just bought FoCal. Actually I paid less using the link I found in some other thread here:

http://www.reikan.co.uk/focal/mbp45/

Not sure if it is still valid - when I asked about it I was told that it would be taken down last Sunday, but it is still there. Since it's an automated process you get your license within few minutes.

As for usefulness. Well, I'm analyzing my camera focusing issue right now. It is a mess, so I'm running lots of test to establish at least single sensor I can use safely. So far it seems that the software produced repeatable results with both daylight and artificial light (500w). My case is a bit extreme, so I can see how this software helps me.

As lots of people pointed out - calibration is not exact science and there are a lot of variables here. I would guess that using such software you can get a feel of your camera and lens performance, but it's unlikely you'd be able to adjust it to ideal conditions, especially zoom lenses.

Alex
http://www.yermakov.net

After purchasing a 24-70 f/2.8 my images were no where what I expected. Soft eyes, things seemed out of focus, etc. I purchased FoCal to help with tuning my lenses and after wasting hours on top of hours trying to get my 24-70 tuned, the results were all over the place, so I would recommend skipping it. One time it was -16 then -3 then -11 then +4 then... then... then... then...

Right now, I look at FoCal as the equivalent to any golf swing instruction aid, completely useless at achieving anything except for making my wallet lighter.

In the end, it turns out, I just upped my shutter speed from 1/FL to 1.5 or 2x local length and all of a sudden my images got razor sharp (with Fine Tune disabled) so I was performing Problem Determination on the wrong tool. The problem wasn't the lens, it was the photographer. Even if the problem was my equipment, I have no faith that FoCal would have helped at all.

But that's just my experience with it.

Nikon D800 | 24-70mm f/2.8G | 70-200mm f/2.8G VR II

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The other option is Focus Tune which is $29.95.

http://michaeltapesdesign.com/focustune.html

Thank you all. I did some more "testing" with different lenses and found much more pleasing results.
I need to look into it deeper but it appears my left focus issue MAY have been fixed.

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<<After purchasing a 24-70 f/2.8 my images were no where what I expected. Soft eyes, things seemed out of focus, etc. I purchased FoCal to help with tuning my lenses and after wasting hours on top of hours trying to get my 24-70 tuned, the results were all over the place, so I would recommend skipping it. One time it was -16 then -3 then -11 then +4 then... then... then... then...>>

Sadly a repeat of my problems posted elsewhere with the 24-70mm with LensAlign and FocusTune much it seems to the annoyance of some! However, I do have some faith in my system, although I was losing my cool with zooms, the repeatability was much better with primes. My 300mm f4 analysis actually returned 3 times an AF-fine tune of zero! My opinion is that zooms are a hit or miss issue and best left alone. That said, I have returned all my AF-fine tune settings to zero, upped my technique as you have by increasing speed. Job done

Richard

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