D7000 with Nikon 16-35 F4 backfocus issues


Agree with dd regarding AFMA-ing for the value of best compromise.

Not just for zoom lenses at varying focal lengths, for the case of large aperture 1.4 primes, a slight change in focusing distance may also change the AF characteristics by heaps and bounds. Different lighting conditions and color temperature, backlight etc will further wreak havoc to the overall consistency of PDAF systems. Best to test at a comfortable colour temperature (not too warm, pref. daylight) and make slight adjustments for warm lighting. Cheers!

Good point on choosing the ambient for adjusting focus. Some kinds florescent lighting can cause havoc to focus accuracy too.
 

Thanks for the adv.

From my understanding, is it safe for me to do a testn calibrate if necessary at f/4 @ 40mm (since it is the sharpest from most of the reviews Also at test at f/8 @ 17mm & f/4 @ 70mm as well to see if any difference.
 

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Thanks for the adv.

From my understanding, is it safe for me to do a testn calibrate if necessary at f/4 @ 40mm (since it is the sharpest from most of the reviews Also at test at f/8 @ 17mm & f/4 @ 70mm as well to see if any difference.

Problem with testing at wide angles is, the DOF will not be so thin since the FOV is so wide, you will have trouble figuring out if the focus is spot on or not.
 

Problem with testing at wide angles is, the DOF will not be so thin since the FOV is so wide, you will have trouble figuring out if the focus is spot on or not.

best way to check lenses of this class is to evaluate the bluriness of the background & foreground. it is not essential to have perfect 1/2 front & 1/2 back DOF & will depend on whether u prefer slight front focus or slight backfocus. eg. portrait slight front focus is pleasing for smoother background & the opp for landscapes as it is easy to achieve a reading closer to hyperfocal.
 

AF fine tune is specific to the lens used. It does not care about focal length nor aperture. Usually we calibrate the lens at or near the longest focal length of a zoom lens. Do note that some lenses do exhibit focus shift (different focus point at different focus distance/aperture). So if that is the situation, either find a point where it is the best compromise, or send your lens in to get it looked at. Sometimes it is the characteristic of the lens and there is nothing you can do about it. In that case, tune your AF at the focal length/aperture/focus distance you are most likely to use.

Hi Daredevil,
For canon, I heard it goes by serial number. For Nikon, the afma goes by the lens focal length n aperture. Meaning if u tune afma for a 85mm f1.4 n u mount another lens, the same afma is applied. Not sure if the body will differentiate between afd n afs lens though. But I did test on 2 x 85mm f1.4g before. For canon, they can have 2 afma for zoom lens. Nikon should have done that. Regarding the last part, how would we know that it's the lens characteristic n not manufacturer fault?
Thanks. :)
 

Hi Daredevil,
For canon, I heard it goes by serial number. For Nikon, the afma goes by the lens focal length n aperture. Meaning if u tune afma for a 85mm f1.4 n u mount another lens, the same afma is applied. Not sure if the body will differentiate between afd n afs lens though. But I did test on 2 x 85mm f1.4g before. For canon, they can have 2 afma for zoom lens. Nikon should have done that. Regarding the last part, how would we know that it's the lens characteristic n not manufacturer fault?
Thanks. :)

It goes by the type of lens. If you mount 2 lenses of the exact same model, afma will be applied. But if one is a zoom and another is a prime, they will be different. Question is, how many people out there will own 2 copies of the same exact lens and swap between them often. If you are one of those minority, you might want to consider sending one of your lens in. And for afma, you can always turn it on or off. Just program that menu item into your shortcuts.
 

It goes by the type of lens. If you mount 2 lenses of the exact same model, afma will be applied. But if one is a zoom and another is a prime, they will be different. Question is, how many people out there will own 2 copies of the same exact lens and swap between them often. If you are one of those minority, you might want to consider sending one of your lens in. And for afma, you can always turn it on or off. Just program that menu item into your shortcuts.

Hi Daredevil,
For the second part, I was referring to your previous post that we should send the zoom in to NSC if let's say the afma is diff at 70mm n 200mm for the 70-200afs vr2 for eg.
Is there any way we can know if that is the characteristic? Or that copy of lens has issue?
And no I don't have 2 copies of same lens. :) But I happen to goto NSC to demo n i went to a shop to test n I thought nikon would afma based on serial, but it didn't.
Thanks
 

Hi Daredevil,
For the second part, I was referring to your previous post that we should send the zoom in to NSC if let's say the afma is diff at 70mm n 200mm for the 70-200afs vr2 for eg.
Is there any way we can know if that is the characteristic? Or that copy of lens has issue?
And no I don't have 2 copies of same lens. :) But I happen to goto NSC to demo n i went to a shop to test n I thought nikon would afma based on serial, but it didn't.
Thanks

Based on my knowledge, they will be happy to fix this discrepancy between the wide-tele ends. Other than that, simple issues with AFMA should be done by yourself.
 

Based on my knowledge, they will be happy to fix this discrepancy between the wide-tele ends. Other than that, simple issues with AFMA should be done by yourself.

It is not fixable some times.
 

It is not fixable some times.

i think they will map out a curve of AF adjustment values for the focal lengths... so i think you're right, if too severe may not be fixable
 

Forgotten about this thread totally. Just to highlight I sent my D7000 to NSC to service the back focus issue couple of months ago. Problem resolved as they did some hardware fine tuning. Now my lens are able to focus properly with the D7000. happy ^^
 

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