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03-06-2020, 02:54 PM - 1 Like   #1
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Vintage lenses fouling KP mirror

Just a bit of a heads up. Today I was shooting with an M42 Auto Yashinon DX 50mm f1.7. Whenever I focused further than 3m it fouled on the mirror. The yashika DX protrudes quite a bit from the rear, as does the Auto Yashinon 55m f1.8 and the Auto Mamiya Sekor 50mm. I presume they are all a similar design. If this is the case, the Auto Chinon will be another lens to watch. All of these are attributed to Tomiokas and are incredibly sharp. They are fine on the K3 but not on the KP. I had a similar issue with a Schneider Kreuznach 135mm edixa tele xenon and my K30, once again the K3 was fine. Takumar are fine on the KP but watch your tomiokas!


Last edited by Cerebum; 03-06-2020 at 03:04 PM.
03-06-2020, 03:12 PM   #2
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Would using a different M42 to K adapter help?
03-06-2020, 03:16 PM   #3
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QuoteOriginally posted by Cerebum Quote
They are fine on the K3 but not on the KP.
That is strange. The mirror on the KP should have a ton of clearance for any lens originally intended for a 35mm film SLR.* Are you confident that the lens has not been modified to allow beyond-infinity focus when adapted to mirrorless? How are you determining that the mirror is fouled? Does it fail to rise? Have you actually tested this lens on both the K-3 and the KP?


Steve

* I would be surprised if it did not share mirrors with the K-3. If by some chance, it has an articulated mirror such as on the K-1, I would expect the same or more rather than less clearance through most of its entire travel.
03-06-2020, 03:18 PM   #4
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The Yashinon DX 1.7 is known for that -- don't try to put it on a K-01 either even though it has no mirror. I'm not sure it is fine on the K3 either (it is not fine on the K-5) -- I doubt it is at infinity.

03-06-2020, 03:21 PM   #5
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QuoteOriginally posted by rawr Quote
Would using a different M42 to K adapter help?
Presumably a different adapter would affect focus

---------- Post added 03-06-20 at 03:23 PM ----------

QuoteOriginally posted by stevebrot Quote
That is strange. The mirror on the KP should have a ton of clearance for any lens originally intended for a 35mm film SLR.* Are you confident that the lens has not been modified to allow beyond-infinity focus when adapted to mirrorless? How are you determining that the mirror is fouled? Does it fail to rise? Have you actually tested this lens on both the K-3 and the KP?


Steve

* I would be surprised if it did not share mirrors with the K-3. If by some chance, it has an articulated mirror such as on the K-1, I would expect the same or more rather than less clearance through most of its entire travel.
When you take the shot the view finder stays dark, as you dial in the focus or unscrew the lens a little the mirror drops. I have used it lots on the K3, it is wonderful

---------- Post added 03-06-20 at 03:25 PM ----------

QuoteOriginally posted by vonBaloney Quote
The Yashinon DX 1.7 is known for that -- don't try to put it on a K-01 either even though it has no mirror. I'm not sure it is fine on the K3 either (it is not fine on the K-5) -- I doubt it is at infinity.
I thought that was the SX, my understanding is that the DX is fine. The auto Yashinon 55mm protrudes but I didn't try it. Maybe I should [COLOR="Silver"]

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03-06-2020, 03:30 PM   #6
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Now that I think about it I think my memory is failing me whether I actually had trouble with it or not. (Not eager to go test that) However, that lens is definitely a problem with full-frame cameras besides the original one it was meant for -- I believe later model Yashinon film bodies even had a warning about using it. I think what it was is that some people were having trouble with it on Pentax APS-C bodies (at infinity) and some weren't. Probably specific to your copy of the lens. And I do recall thinking "Ok, well it should be fine on my K-01 with no mirror" and then finding out it wasn't because the "mirror box" wasn't big enough and it would just bang into the edge. So maybe the issue is not only that it protrudes quite far, but also that the part that is protruding is of usually wide diameter?
03-06-2020, 03:37 PM   #7
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QuoteOriginally posted by vonBaloney Quote
Now that I think about it I think my memory is failing me whether I actually had trouble with it or not. (Not eager to go test that) However, that lens is definitely a problem with full-frame cameras besides the original one it was meant for -- I believe later model Yashinon film bodies even had a warning about using it. I think what it was is that some people were having trouble with it on Pentax APS-C bodies (at infinity) and some weren't. Probably specific to your copy of the lens. And I do recall thinking "Ok, well it should be fine on my K-01 with no mirror" and then finding out it wasn't because the "mirror box" wasn't big enough and it would just bang into the edge. So maybe the issue is not only that it protrudes quite far, but also that the part that is protruding is of usually wide diameter?
Hmmm, like I said, the protrusion on the super sexy auto Yashinon 55mm f1.8 is similar. I will whack it on and do a quick test. Maybe it isnt as simple as how far it sticks out. ........ Maybe it is just that lens.......... Have I started another thread without foot reason again? I normally only do that when there is a competition lolol

03-06-2020, 03:38 PM   #8
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QuoteOriginally posted by Cerebum Quote
I thought that was the SX, my understanding is that the DX is fine. The auto Yashinon 55mm protrudes but I didn't try it. Maybe I should
The SX, meaning the Mayima? From what I remember, the Yashinon-DX 50/1.7 is the absolute worst lens ever as far as hitting mirrors -- even the DX/1.4 I think is ok (don't quote me on that). And probably the others you mention unless you've found out differently. (And I've got copies of all of those, don't think I've had that particular trouble with any of them.) There are are couple of others known for hitting mirrors on full-frame that I can't recall right now, but I don't think they were all in the same family or even necessarily adaptable to Pentax (Canon lenses, etc). As far as APS-C, the Yash DX/1.7 is the only one that comes to mind.

BTW, the later Yash DS-M 1.4 & 1.7 50s are totally fine in that regard and even better optically, although not as cool-looking...
03-06-2020, 03:43 PM   #9
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QuoteOriginally posted by Cerebum Quote
I thought that was the SX, my understanding is that the DX is fine.
I thought the problem was with Mamiya/Sekor SX. The Yashinon DX and DS series have no previous reputation that I am aware of except that the DS have no auto/manual switch.


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03-06-2020, 03:51 PM   #10
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QuoteOriginally posted by vonBaloney Quote
From what I remember, the Yashinon-DX 50/1.7 is the absolute worst lens ever as far as hitting mirrors
The lens has a protective "collar", but I don't see from photos on the Web that it is any more prominent or larger diameter than the similar collar on my Auto Rikenon 50/1.7 (3cm diameter intruding 1cm past the lens flange at infinity). If you are thinking adapted to FF Canon, that would make more sense than problems with other than Yashica M42 or a general problem adapted to Pentax-K.


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03-06-2020, 04:02 PM   #11
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QuoteOriginally posted by stevebrot Quote
The lens has a protective "collar", but I don't see from photos on the Web that it is any more prominent or larger diameter than the similar collar on my Auto Rikenon 50/1.7 (3cm diameter intruding 1cm past the lens flange at infinity). If you are thinking adapted to FF Canon, that would make more sense than problems with other than Yashica M42 or a general problem adapted to Pentax-K.
It doesn't work on the K-01, that's what I remember. I can try it again just to make sure I'm not making things up.

The Mamiyas some of them you have to file down the aperture ring to mount it, but I haven't any infinity mirror-fouling problems. But I haven't used them much -- my copies had tended to have Schneideritis and have a hotspot when stopped down.
03-06-2020, 04:14 PM   #12
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Ok, the DX just and so touches the mirror on the K3. It is barely noticeable, that’s why I didn’t notice it. The auto Mamiya Sekor 50mm f1.7 and the auto Yashinon 55mm f1.8 are fine, which is great as they are amongst my absolute favourites. I hadn’t used manual lenses extensively with the KP and jumped to a conclusion. Sorry guys.

My DX is now a mirrorless lens and is on the list of potential sacrifices should my financial situation get any worse
03-06-2020, 05:18 PM   #13
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QuoteOriginally posted by vonBaloney Quote
It doesn't work on the K-01, that's what I remember. I can try it again just to make sure I'm not making things up.
I just did some look-see and measuring of the mirror box on my K-3 and can see that the collar on my Rikenon 50/1.7 (1st cousin to the Yashinon DX 50/1.7) might be a very tight fit on that camera and may not clear at all if the lens rear intrudes even a little more the camera designer's expectations and at a little larger diameter. I suspect that the K-01 may be even tighter than the K-3.

As for mirror clearance, the situation on the K-3 is a little more complex than I would have thought. As the mirror rises, a baffle unfolds from its underside that has potential to contact the lens rear. I suspect that is what catches on @Cerebrum 's lens. The mirror clearance is fine, but the baffle clearance is tight.


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03-06-2020, 05:23 PM   #14
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QuoteOriginally posted by stevebrot Quote
I just did some look-see and measuring of the mirror box on my K-3 and can see that the collar on my Rikenon 50/1.7 (1st cousin to the Yashinon DX 50/1.7) might be a very tight fit on that camera and may not clear at all if the lens rear intrudes even a little more the camera designer's expectations and at a little larger diameter. I suspect that the K-01 may be even tighter than the K-3.

As for mirror clearance, the situation on the K-3 is a little more complex than I would have thought. As the mirror rises, a baffle unfolds from its underside that has potential to contact the lens rear. I suspect that is what catches on @Cerebrum 's lens. The mirror clearance is fine, but the baffle clearance is tight.
The K-01 has a low overhang where the mirror would flip-up/focusing screen area would be, and the DX/1.7 just crushes into that if you start focusing toward infinity (assuming it was away from infinity when you mounted it) and so you could do some real damage that way...
03-06-2020, 05:35 PM - 1 Like   #15
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QuoteOriginally posted by vonBaloney Quote
The K-01 has a low overhang where the mirror would flip-up/focusing screen area would be, and the DX/1.7 just crushes into that if you start focusing toward infinity (assuming it was away from infinity when you mounted it) and so you could do some real damage that way...
I need to start a list of these sort of things to add to an article on adapted M42 lenses that has been simmering on the back burner for quite a while.


Steve
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