Lens Calibrate with Nikon D6

[mdavis501]

I'm trying to calibrate the Nikon 500mm f/4 and the D6. Michael Tape's excellent Focustune doesn't work with the new D6 EXIF file(s) and I got the impression that he won't be adding that camera to work with focustune. Trying to work with just the LensAlign physical tool by choosing different lens adjust value and evaluating the jpeg images in Photoshop (even using the emboss filter to emphasize which ruler numbers were sharper) just didn't produce reliable results. I consistently got the number just below the 0 on the LensAlign ruler (the number 8) to be sharp no matter what lens adjust value I used.

So, having read Steve's excellent book on Nikon AF, I decided to print Steve's target and tape it to my garage door (the only one my wife would allow to be used). Maybe my wife knows Steve's wife, don't know. Then I lit it nicely and evenly. Then did the Auto fine tune in the D6. 41 feet from the taped, well lit target. Lightly touching "OK" sign to coach the d6 to do its auto adjust. Threw out the high and low values, and averaged the rest. Just seems to be too much variation. +2 on Monday. Re-do it and get +5 on Wednesday.

I don't think it's the lens. The lens calibrates nicely with the D850 and produces excellent results.

Any other thoughts on how to get consistent AF adjust numbers on the D6?

 

[soundbyte]

You might try the Dot Tune method, not the in camera option.

.
It takes a little to get used to what you are doing but after that it is probably less than 5 minutes per test for each lens / camera combination you might have.
I used Steve Perry's target and had good success, BUT make sure you have the target well lit otherwise you may get odd results.

You can only see EXIF info for this image if you are logged in.

 

[Warren D]

I used the lens align target and just repeated the test about 20 times. I used single point AF, single shot af (not continuous). Values will vary because of the nature of the af system. I started to observe that my D6 had the same front focus bias that the rest of my bodies have, which makes sense as the factory calibration should be similar. For a good ballpark, if your D850 has, for example, 8 units of FF (AFFT +8) for your 500 f4, then that's the value I'd start with for the D6. Just a warning, if your D850 has ever been in for repair to either Nikon or one of their authorized repair stations, this won't work as the AF calibration of the repair units are about 7 units off factory. (You would need to add +7 units AFFT to compensate for the repair bias)
The dot tune method works, too. I have found that AFFT can vary with temperature so a value I'll use in the summer isn't the same as what I'll use in the winter. Be wary of heat waves if doing the AFFT outdoors, they will lead to inconsistant readings and you can't always see them.

 

[gordon_g]

I'm trying to calibrate the Nikon 500mm f/4 and the D6. Michael Tape's excellent Focustune doesn't work with the new D6 EXIF file(s) and I got the impression that he won't be adding that camera to work with focustune. Trying to work with just the LensAlign physical tool by choosing different lens adjust value and evaluating the jpeg images in Photoshop (even using the emboss filter to emphasize which ruler numbers were sharper) just didn't produce reliable results. I consistently got the number just below the 0 on the LensAlign ruler (the number 8) to be sharp no matter what lens adjust value I used.

So, having read Steve's excellent book on Nikon AF, I decided to print Steve's target and tape it to my garage door (the only one my wife would allow to be used). Maybe my wife knows Steve's wife, don't know. Then I lit it nicely and evenly. Then did the Auto fine tune in the D6. 41 feet from the taped, well lit target. Lightly touching "OK" sign to coach the d6 to do its auto adjust. Threw out the high and low values, and averaged the rest. Just seems to be too much variation. +2 on Monday. Re-do it and get +5 on Wednesday.

I don't think it's the lens. The lens calibrates nicely with the D850 and produces excellent results.

Any other thoughts on how to get consistent AF adjust numbers on the D6?

What kind of driveway do you have?? are you getting heat refraction off the blacktop / concrete / Stones??

 

[mdavis501]

You might try the Dot Tune method, not the in camera option.

.
It takes a little to get used to what you are doing but after that it is probably less than 5 minutes per test for each lens / camera combination you might have.
I used Steve Perry's target and had good success, BUT make sure you have the target well lit otherwise you may get odd results.

View attachment 8554

Thank you. I'm definitely going to try the Dot Tune method.

 

[Steve]

The bigger question is do you have a problem? I don't recommend tuning lenses just for the sake of it. Whenever I get a new camera or lens, I test it both with targets and in the real world to see if I am seeing either consistent front or back focus. Most of the time, the lens is fine from the factory, however, if I do see a problem, it's only then that I actually try to tune the lens. I've seen a LOT of people tune lenses only to end up with results that were far worse than had they not messed with it.

 

[Thern]

The bigger question is do you have a problem? I don't recommend tuning lenses just for the sake of it. Whenever I get a new camera or lens, I test it both with targets and in the real world to see if I am seeing either consistent front or back focus. Most of the time, the lens is fine from the factory, however, if I do see a problem, it's only then that I actually try to tune the lens. I've seen a LOT of people tune lenses only to end up with results that were far worse than had they not messed with it.

EXACTLY, this is exactly the same I said in another thread.
People do think they really should AFFT their lenses, introducing problems by ‘solving’ a non existent problem.

To quote Nikon...

AF tuning is not recommended in most situations and may interfere with normal focus; use only when required.

Service note: If your lens has a focus problem you should return it to Nikon Service as AF Fine-Tune is not intended to solve optical problems which will generally be outside of scope for this tool. If you have a focus problem which is always present with different lenses then this would indicate a camera setting issue

 

[mdavis501]

The bigger question is do you have a problem? I don't recommend tuning lenses just for the sake of it. Whenever I get a new camera or lens, I test it both with targets and in the real world to see if I am seeing either consistent front or back focus. Most of the time, the lens is fine from the factory, however, if I do see a problem, it's only then that I actually try to tune the lens. I've seen a LOT of people tune lenses only to end up with results that were far worse than had they not messed with it.

I see the point here -- however, it seems that if I could get a reliable adjustment (I realize that is a big IF) then it would be better than saying, hey my images look right. It's difficult with not traveling much due to covid to actually test on animals. I guess I will try using my dog, he's always willing to run around and pose.

 

[mdavis501]

The bigger question is do you have a problem? I don't recommend tuning lenses just for the sake of it. Whenever I get a new camera or lens, I test it both with targets and in the real world to see if I am seeing either consistent front or back focus. Most of the time, the lens is fine from the factory, however, if I do see a problem, it's only then that I actually try to tune the lens. I've seen a LOT of people tune lenses only to end up with results that were far worse than had they not messed with it.

I did not know that most of the time the lens and the camera body are properly calibrated. I thought the opposite -- that the chances of this body happening to match the tolerences of a lens manufactured at a different time would be remote. I will check my lenses on a live subject and see if I can see any type of focus error. Thank you.

 

[Steve]

I see the point here -- however, it seems that if I could get a reliable adjustment (I realize that is a big IF) then it would be better than saying, hey my images look right. It's difficult with not traveling much due to covid to actually test on animals. I guess I will try using my dog, he's always willing to run around and pose.

And remember - shoot wide open and you're looking for consistent front or back focusing - if you see a bit of both, it's not a calibration issue. OTOH, if every shot is focused slightly ahead of or behind where it should be, time to AFFT. On my D6, pretty much every lens I have was perfect - I think I only had one that needed a bit of an adjustment.