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Hai
Tinkerer
Username: Hai
Post Number: 16
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 14, 2009 - 04:46 am: | 
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How does the Kodak IIIS lenses brings up the correct framelines? I have Kodak lenses I want to modify, but I don't want them to loose the automatic framlines when I attach them to the IIIS... |
Ezio
Tinkerer
Username: Ezio
Post Number: 16
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 14, 2009 - 07:31 am: |
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If you look at the lens breech mount without a lens, you will notice a small pin protruding from a hole in the left/lower part of the ring. That pin engages into the lens' mount, and perform two functions: the first few mm of the pin being pressed down by the lens determines the automatic framelines (you can see this by gently pressing down the pin by hand, of course without a lens); further pressure establishes the connection between the lens and the rangefinder.
Rick Oleson has a very clear diagram of the whole thing.
Clearly, the framelines are determined by very slight differences in the part of the lens mount that presses against the pin (it looks like a curved groove or recessed section, for lack of a better term). |
Hai
Tinkerer
Username: Hai
Post Number: 17
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 16, 2009 - 08:31 am: |
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Thanks... I wonder how the same pin deals with the auto-framelines AND the range finder?
Anyway - now I am sure that modifying my lens will not affect the auto-framelines... |
Ezio
Tinkerer
Username: Ezio
Post Number: 17
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 16, 2009 - 12:08 pm: |
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Well, if you take a good look you'll notice that the pin goes through both a first supporting section and a main back elemen, an that in the space between the two it is surrounded by sort of annular sabot. The sabot is what sets the framelines, while at the pin gets pushed further back through the sabot (which is blocked against
the back element) it governs the rangefinder.
If your proposed modification involves doing the small cut-off that enables use of these lenses on a Bessamatic, go on. I've done it, and there are no problem. |
Hai
Tinkerer
Username: Hai
Post Number: 18
Registered: 05-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 18, 2009 - 06:56 am: |
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Thanks a lot. I am modifying these lenses to fit Baldamatic and not Bessamatic, that's why I needed this extra verification... |
