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08-22-2011, 03:09 AM   #1
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Dumb Question: Adapted Leica lenses on film bodies? Why not???

I am sure this must be a dumb question, so apologies in advance.

Basically my adapted Leica R lenses (with Leitax or Pixco R to K adapters) can't be fitted to my film bodies. Why?

I tried on the MZ-5n and the LX and no go. Something's in the way. Will they fit on an MZ-6? What's actually the problem?

08-22-2011, 03:18 AM   #2
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The M lenses are designed for rangefinder cameras, which are mirrorless. If you adapt an M-lens to a full frame camera, the mirror collides with the backside of the lens. BTW: It's not really healthy for the camera mechanics.
08-22-2011, 03:21 AM   #3
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Hi ICG!

Well, when I said "Dumb question" I didn't mean that dumb.

And if you read my post, I did say "R lenses" and "adapted to K", but hey, who has time to read posts one is replying to these days, especially ones titled "Dumb Question"?

To make it perfectly clear - these lenses are adapted to Pentax K-mount and work fine with my dSLRs. Just not the film SLRs.
08-22-2011, 03:34 AM   #4
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It's still the same problem. The lenses were produced for a larger flange back length (47mm), and the back of the lens collides with the mirror. The Pentax DSLRs have a smaller, shorter mirror because of the crop factor and therefore it doesn't hit the lens.

08-22-2011, 04:08 AM   #5
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Right, so you are saying it's because of the large mirror in the film SLRs. Yep, I buy that.

Last edited by DanielT74; 08-22-2011 at 04:31 AM.
08-22-2011, 10:37 PM   #6
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QuoteOriginally posted by ICG Quote
It's still the same problem. The lenses were produced for a larger flange back length (47mm), and the back of the lens collides with the mirror. The Pentax DSLRs have a smaller, shorter mirror because of the crop factor and therefore it doesn't hit the lens.
QuoteOriginally posted by DanielT74 Quote
Right, so you are saying it's because of the large mirror in the film SLRs. Yep, I buy that.
Daniel, please post a picture of the Leica lens with the mount pointing up. I want to see how much the Leica protrudes beyond the PK mount. When you say the Leica lens won't 'fit on an SLR, does it mean it won't mount or you can't trip the shutter? If ICG's assertion that the mirror collides with the back of the lens is correct, they should only collide when the mirror is flipping up to expose the film. That's quite the hefty force generated when the mirror is being flipped up, I would imagine either the lens or the mirror and/or both would be damaged if such collision do occur.

Thanks,
08-22-2011, 10:58 PM   #7
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Yep, it's the mount adapter! I just remembered I took a bunch of film pics last year with the Summilux-R 35mm, which has the most protruding rear element of all.

But it has the Leitax adapter and the Summilux-R 50mm has the Pixco adapter. There's the rub! And here i the pic of the two:

Last edited by DanielT74; 06-11-2012 at 03:06 AM.
08-22-2011, 11:56 PM   #8
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How much is the lens protruding from the base of the K mount? If you could take a picture showing the side view we could get a better idea of the amount of the protrusion. I have some Schneider-Kreuznach and Voightlander Retina lenses I am using with a DKL to M42 adapter plus an M42 to PK adapter. The M42 to PK adapter is the infinity type with inner flange for keeping the aperture pin depressed. This adapter protrudes about 8mm into the mirror box, measured from the base of the DKL mount and there is no interference between the mirror and the lens mount. I think there is another 1 or 2mm to go before the mirror flipping up might start brushing against any protrusion.

Thanks,

08-23-2011, 02:58 AM   #9
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It's definitely not the lens protrusion because the Summilux 35mm mounts just fine with the Leitax mount and the rear element here protrudes a hell of a lot. It must be the adapter which strangely fits fine on the K20 and K-5 but not on MZ-5n and LX. What is the difference between these mounts? I will take some more detailed pics now (with a flash and my wife's Panasonic LX-3 (my dSLRs are out of commission for the moment).
08-23-2011, 08:34 AM   #10
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This is just a guess, but it might be the aperture follower tab (probably not the right name for it). On an uncrippled mount, this tab is in the right upper quadrant of the mount. There's a corresponding slot and tab in a K-mount lens that moves when the aperture ring moves. The DSLRs have no tab there. Your photos show a machined slot where the tab should go, but maybe this slot is not deep enough on the adapter that doesn't fit.
10-26-2011, 12:05 AM   #11
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well……I use it once everything is OK
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