Film-Tech Forum ARCHIVE: Focus Issue With A Kinoton FP-23

This is topic Focus Issue With A Kinoton FP-23 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mitchell Dvoskin (Member # 751) on 11-16-2006, 12:21 PM:

I have a focus issue with a Kinoton FP-23. It seems that the right side of the picture is not in focus when the left & center is. It gets worse, the further to the right you look. It is not significantly out of focus, and I can usually get a compromise focus that is livable, but not as razor sharp as it should be. This is not a new problem, and I recently replaced the skate and runners which had no effect on the problem.

Most likely, either the film gate or the manually torret is slightly out of alignment, but there does not appear to be an adjustment for either.

Looking for suggestions.

Posted by Brian Guckian (Member # 1678) on 11-17-2006, 09:56 AM:

It could be misalignment of the lens sleeve in the turret. As you know, the lens sleeves can "float" up-down and left-right once the screws locking them to the face of the turret are slackened off.

If the lens is way off-centre, depending on how the other lenses are lined up, then this could be the reason.

The other thing to look for is how the lens is sitting in the barrel. If the lens body is forward in the barrel, it's possible that one of the locking thumbscrews isn't gripping it properly or is pushing the lens slightly out of true. Or, the lens just isn't sitting exactly straight within the sleeve.

Also, if the ceramic discs in the gate that apply lateral tension are locked up, worn or misaligned that could also account for focus problems.

Hope this helps.

Posted by John Anastasio (Member # 607) on 11-21-2006, 04:20 PM:

I had the same exact problem with my Christie, Mitch...and it was the lens that was out of alignment. In my case, it was caused by the entire turret being allowed to close too far by the metallic stop designed to prevent that. A quick turn of the locking nut to readjust it and the focus was clear over the entire screen.

Posted by Robert John Jeromson (Member # 2559) on 11-21-2006, 06:14 PM:

I have had issues in the past with focus variation between the top and bottom of the screen with the lens just slightly out of alignment.

I suggests you start there and also with the lens barrel, though the can be really fiddly to get into the right place. I stongly suggest using an RP-40 test film.