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Stewart
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 19, 2005 - 06:38 pm: | 
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Hi. I've never repaired a camera before but recently acquired a jammed Canonet QL25 which I thought I would try and get working. So far I have got the shutter and diaphragm working nicely by virtue of lighter fluid and graphite dust. Unfortunately when removing the front lens elements, in my ignorance I removed the retaining ring which holds the elements into the little barrel and they all fell out. My dumb question is as follows: when putting them back, do all the elements have the convex side forwards? |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 19, 2005 - 08:04 pm: |
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I'm not sure what the construction of the QL25 lens is. In general, lens elements tend to be most convex on the side away from the diaphragm, so front elements are convex-forward and rear ones are convex-rearward (if an element is convex on both sides, the side with flatter curvature usually faces the diaphragm). This is a generalization though, and there are exceptions. In a triplet or tessar type, there is a central element that's concave on both sides, and it's generally not symmetrical.... this one can be a matter of trial and error if you lose track of it.
rick : ) = |
dmr
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 21, 2005 - 12:01 pm: |
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Hi Stewart. I have never repaired a camera before either, and I just got a jammed QL17 GIII.I'm going thru the slow process of learning and repairing simultaneously, with lots of help from the people over at Rangefinder Forum.
Your QL25 is most likely the same camera we gave my dad after he retired. He was a roll-film fan who swore years before that he would "never go 35".  He eventually admitted that it was his favorite camera of all times.
Anyway, from just having disassembled the front part of the QL17, I can very definitely say that the convex side of the front lens faces out. If it's similar to the QL17, the center and rear elements appear to go in only one way. |
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