Might try the new Sigma DP1...

er1kksen · 10-02-2010, 05:52 AM

Originally posted by Blue

The Sigma SA and EOS have a 44mm registry distance. Pentax is 45.46.

So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose.

JohnBee · 10-02-2010, 06:41 AM

Originally posted by er1kksen

So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose.

You can add distance but you can't take it off

Blue · 10-02-2010, 09:22 AM

Originally posted by er1kksen

So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose.

With the correct adapter, the focus scale would be o.k. along with infinity. That's why so many people use a Canon body for so many vintage lens mounts. The irony is that with exception of a few Canon FD-EOS adapters such as the EOS-FD macro which I have a copy of, they can't use their vintage FD and FL lenses and there are many excellent ones including some L glass.

The Sigma should be no difference in that regard for various mounts that have a longer registration distance.

Edit: One function of the adapter is to get the correct registration distance for that particular lens mount.

er1kksen · 10-02-2010, 01:49 PM

Originally posted by Blue

With the correct adapter, the focus scale would be o.k. along with infinity. That's why so many people use a Canon body for so many vintage lens mounts. The irony is that with exception of a few Canon FD-EOS adapters such as the EOS-FD macro which I have a copy of, they can't use their vintage FD and FL lenses and there are many excellent ones including some L glass.

The Sigma should be no difference in that regard for various mounts that have a longer registration distance.

Edit: One function of the adapter is to get the correct registration distance for that particular lens mount.

Yes I know, but I was asking because I'm under the impression that the Sigma mount is physically identical to the K-mount but with a shorter registration distance and EOS-knockoff electronics and contacts? So you could technically mount a K-mount lens straight on it, provided it doesn't have parts protruding into the camera, and the focus scale would just be wrong due to the changed register difference?

Blue · 10-02-2010, 02:25 PM

Originally posted by er1kksen

Yes I know, but I was asking because I'm under the impression that the Sigma mount is physically identical to the K-mount but with a shorter registration distance and EOS-knockoff electronics and contacts? So you could technically mount a K-mount lens straight on it, provided it doesn't have parts protruding into the camera, and the focus scale would just be wrong due to the changed register difference?

The registration distance would be too close for k-mount lenses. If there was a zone that focused, it would vary by lens if it could focus at all. In theory, it may go beyond infinity. However, it shouldn't be much of a problem correcting the distance. It really depends on the metering etc of the Sigma body whether this body would be useful in this manner.

Edit: Here is a thread on this very topic. I would consider opting to setup swappable body mounts.

http://www.fredmiranda.com/forum/topic/941741

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10-02-2010, 05:52 AM	#16
er1kksen Veteran Member Join Date: Oct 2008 Location: Forestville, NY Photos: Albums Posts: 1,801	Originally posted by Blue The Sigma SA and EOS have a 44mm registry distance. Pentax is 45.46. So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose.

10-02-2010, 06:41 AM	#17
JohnBee Veteran Member Join Date: Sep 2008 Location: Newrfoundland Photos: Albums Posts: 4,667 Original Poster	Originally posted by er1kksen So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose. You can add distance but you can't take it off

10-02-2010, 09:22 AM	#18
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	Originally posted by er1kksen So you could mount it (assuming back protrusions don't interfere with other parts of the mount) but the focusing scale would just be wrong? Basically it would focus past infinity (however that works) for the first 1.46mm of focus travel, I suppose. With the correct adapter, the focus scale would be o.k. along with infinity. That's why so many people use a Canon body for so many vintage lens mounts. The irony is that with exception of a few Canon FD-EOS adapters such as the EOS-FD macro which I have a copy of, they can't use their vintage FD and FL lenses and there are many excellent ones including some L glass. The Sigma should be no difference in that regard for various mounts that have a longer registration distance. Edit: One function of the adapter is to get the correct registration distance for that particular lens mount.

10-02-2010, 01:49 PM	#19
er1kksen Veteran Member Join Date: Oct 2008 Location: Forestville, NY Photos: Albums Posts: 1,801	Originally posted by Blue With the correct adapter, the focus scale would be o.k. along with infinity. That's why so many people use a Canon body for so many vintage lens mounts. The irony is that with exception of a few Canon FD-EOS adapters such as the EOS-FD macro which I have a copy of, they can't use their vintage FD and FL lenses and there are many excellent ones including some L glass. The Sigma should be no difference in that regard for various mounts that have a longer registration distance. Edit: One function of the adapter is to get the correct registration distance for that particular lens mount. Yes I know, but I was asking because I'm under the impression that the Sigma mount is physically identical to the K-mount but with a shorter registration distance and EOS-knockoff electronics and contacts? So you could technically mount a K-mount lens straight on it, provided it doesn't have parts protruding into the camera, and the focus scale would just be wrong due to the changed register difference?

10-02-2010, 02:25 PM	#20
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	Originally posted by er1kksen Yes I know, but I was asking because I'm under the impression that the Sigma mount is physically identical to the K-mount but with a shorter registration distance and EOS-knockoff electronics and contacts? So you could technically mount a K-mount lens straight on it, provided it doesn't have parts protruding into the camera, and the focus scale would just be wrong due to the changed register difference? The registration distance would be too close for k-mount lenses. If there was a zone that focused, it would vary by lens if it could focus at all. In theory, it may go beyond infinity. However, it shouldn't be much of a problem correcting the distance. It really depends on the metering etc of the Sigma body whether this body would be useful in this manner. Edit: Here is a thread on this very topic. I would consider opting to setup swappable body mounts. http://www.fredmiranda.com/forum/topic/941741