"Left focus" repair attempt in Melville

Started Jan 12, 2013 | Discussions thread
Fayard
Regular MemberPosts: 127
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Re: "Left focus" repair attempt in Melville
In reply to Tymosz, Jan 13, 2013

I've worked on the camera to get a better understanding on what's going on. It is clear to me that the camera frontfocuses by 10 AFFT with the lights in my living room, a problem which was not there before.

In order to AF Fine Tune my camera, I use the following setup: a paper with a line every millimeter is fixed on a book and slanted by 45 degrees. On that paper, I put a vertical target facing the camera. The camera is mounted on a tripod, in AFS mode and for every single situation I take 6 pictures, racking the focus 3 times to infinity and 3 times to close focus before focusing.

Here is what I get with my D800 and the AFS 85mm f1.8, at 2.15 meters from the target with the aperture at 1.8, using the central AF sensor. From left to right:

- Outdoor light, central AF sensor, AF Fine Tune set to +10: Perfect focus

- Indoor light, central AF sensor, AF Fine Tune set to +10: Front focus

- Outdoor light, central AF sensor, AF Fine Tune set to +20: Back focus

- Indoor light, central AF sensor, AF Fine Tune set to +20: Perfect focus

Therefore, I need +10 with the central AF sensor outdoor, and +20 with the same sensor indoor. I have done enough testing before to know that this problem was not there before I sent the camera to Melville. They completely messed up my camera.

I am sending it back to Melville and I hope I will be able to talk to a technician.

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