Canon LTM Lens off - Canonet QL17 GIII

Canon M39 M39 screw mount bodies/lenses
jamesj

jamesj

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Aug 15, 2006
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So im having problems with my canonet QL17 GIII. I replaced the front and rear element since the front had some scratches and the inner element had some spots on it. Well I got it back together and now running film through it the lens is off. I know the rangefinder is lined up correctly. But the lens seems to be off at different f stops, in focus but has a bit of front focus. and then focus is off to the left if that makes sense.

Does anyone have any suggestions on how to fix this.

30th at 1.7

hellokitty.jpg


This was 30th at 2

duff.jpg


30th at 1.7

love.jpg



Focus was on the sign
30th at 1.7

shelf.jpg


here again is where it seems to be focusing to the left.

pens.jpg



then it will make images like this at f4
horse.jpg
 
Hopefully you didn't reverse the front element group, but from the diagram I have, it looks unlikely. Could be something isn't seated correctly, that would give you better focus with a stopped down aperture, and the left side focusing. Never taken one of these apart, but I believe you need to reset the focus with a collimator to get it correct, then it has to be cross-checked with the rangefinder. At least that was the procedure with the older Canonet's.

PF
 
You can't really reverse the front elements, as long as the curved surface faces forward, it is correct. You have to be careful when installing new elements as they will have to be collimated. This is done by adjusting the ring which surrounds the rear element lock ring. I use ground glass and a loupe to check to check focus. You can use the ground glass to make sure focus corresponds to the distances on the focusing ring by adjusting the rangefinder.
 
Last edited:
@frontman that totally makes sense. but a little to advanced for me.
called a shop today and they said they couldn't do it for me.
 
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