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Russell A.
Russell A., Camera and Video Technician
Category: Camera and Video
Satisfied Customers: 5027
Experience:  30 years of experience as a TV station technician gives me a unique understanding of technical equipment issues.
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I have a 300mm f4 Nikon AF-S lens that auto focuses fine on

Customer Question

I have a 300mm f4 Nikon AF-S lens that auto focuses fine on my D300 and my D810 but when attached to my D750 the auto focus won't work. The D750 auto focuses fine with my other lenses. Is the focusing system different on the D750 that the auto focus on the 300mm f4 won't work with it? I've read of other people having a problem with that combination. One person said the dc/dc converter on the lens should be upgraded. What is that, what does it do and why could it be the problem?
Submitted: 1 year ago.
Category: Camera and Video
Expert:  Rick replied 1 year ago.

Is there an ERR message on the camera and does it register the aperture setting?

Customer: replied 1 year ago.
there is on ERR message and the aperture setting registers on the camera.
Expert:  Rick replied 1 year ago.

Ok. First of all, I've never heard of any compatibility issues with Nikon AF-S lenses and any of their camera bodies. After all, lens interchangeability is one of Nikons claim to fame. There can be other issues which will cause the lens not to work on the D750 but will take some disassembly and diagnosis to repair and, since it is a Nikon, both lens and body will need to go to one of their repair facilities. There's one on the East Coast and one on the West Coast. Here's a link to the Nikon site to get you started.

Customer: replied 1 year ago.
Thanks Rick, but I've read of a few people having a problem with this combination. There are threads on dpreview, flickr and I started one on Nikonians where others have said they have had the same problem. There must be something different about the D750 (does the dc/dc converter adjust current level?). Nikon hasn't acknowledged it yet.
Expert:  Rick replied 1 year ago.

This is the first I've heard of this. I'll look into it a little further. But, if the cure is to replace the DC/DC board, it'll have to go to Nikon anyway. They don't sell this part upgrade to independent shops. Otherwise, I could recommend a good low cost shop for you.

Expert:  Rick replied 1 year ago.

I've done some checking with Nikon and, although there is no service advisory out for this particular problem, they do seem to be aware of it. You'll need to contact them directly. In mos cases, Nikon will do the upgrade for free.

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