Changing focusing sreens on the F6

I finally got an F6, and I changed-out the focusing screen from the B type that came with the camera, to the L type. It seems that the split image focus indicator line and the electronic focus indicator dot don't always "agree" on what correct focus is. Also, sometimes the diagonal line of the split image is right in the middle of the center focusing point, and sometimes it is off-center.
Does anyone have any idea what the heck is going on? Did I do something wrong, or is the camera out-of-whack?

Thanks for any help/suggestions!

The focus sensors do not sample in a very tight 'spot' manner. Their radius extends a bit further out of their respective brackets. Also the corner ones sample only towards the inside of their corner (top right samples only left and below). Top and bottom ones behave similarly. This way you can get an idea where your autofocus system searches to achieve optimal focus.

It may happen that optimal focus is found a bit closer or further ahead than the exact point you are aiming at, especially if you are over it and observing at an angle so that contrasty/textured stuff slightly in front or behind it are in the sensor's radius.

Try doing the same tests by focusing on objects, letters etc placed on walls or some other place that is going to be perpendicular to the lens axis. And of course, you can always shoot a test roll and see who is right, the split image or the autofocus system?

Finally, I think the F6, like most modern cameras, needs a good matte focusing screen with random grain, like the B2 for the FE/FM series... the plain B screen is ok but it is optimized for f/2 onwards and might also produce moire on very fine detail...

Thanks for the insights. I "fiddled around" with it some more, and the split image when manual focusing was definitely correct. Long-story-short, I sent it back to Nikon, and now the autofocus is dead-on and the autofocus and split image are in agreement.

MultiFormat Shooter said:

Thanks for the insights. I "fiddled around" with it some more, and the split image when manual focusing was definitely correct. Long-story-short, I sent it back to Nikon, and now the autofocus is dead-on and the autofocus and split image are in agreement.

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So sounds like your AF failed like it did on my F6. Nikon charged me just over $200’to fix. I was v disappointed in this failure as my camera was spotless and had
never been abused etc. I expected a pro Nikon to be more reliable than this. Yours is now the 5th af failure I’ve seen w the F6. I really like mine otherwise and hope this repair will last the period of my ownership.

Huss said:

I really like mine otherwise and hope this repair will last the period of my ownership.

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My camera sounds like yours, in that there wasn't mark on it. Mine had very little, if any, film through it. I did buy it used, though. I love this camera, and likewise, hope the repair fixes it for good.