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07-25-2013, 09:12 PM   #1
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C/Y to K mount adapter

OK, I know there are threads about modding C/Y mount lenses on K mount cameras, and a few years ago there was a thread that said there were no adapters available, but I just saw this...
Amazon.com: Fotodiox PRO Lens Mount Adapter, Contax Yashica (C/Y) Mount Lens to Pentax K (PK) Mount DSLRS Cameras, CY-PK PRO: Electronics
It promises infinity focus as well. I just bought a ML50/1.9, a DSB 28/2.8, and a DSB 135/2.8 (along with a working FX-3 Super, $15 for all..!!!) and want to use them on my K-5II. Does anyone have experience with that adapter, or know of any others that have come on the market in the last few years? What effect do they have on IQ, and is modding them actually something that a novice can do (do the pictures accurately reflect the level of difficulty)? Thanks again.

07-25-2013, 09:41 PM   #2
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The adapter you linked to has a built-in optical element to support infinity focus. Conventional wisdom is that you should expect some decrease in optical performance as a result.


Steve
07-25-2013, 10:22 PM   #3
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The registration distance is really close to Pentax, so it could be a candidate for a mount swap. You could possibly get one of the cheap flanged M42-K adapters and drill holes to match the lens.

This place makes mounts for that purpose, but they don't list any of your lenses, but the instructions should give you an idea of what is involved.
Zeiss Contax lens for Pentax cameras
07-26-2013, 03:00 AM   #4
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Good Morning,

Several things come to mind here. Here is a similar post on a similar adapter from around this time last year.The main difference is the original poster in the link had a $1500 lens (the 85/1.4) and really should go the lens mount swap route (at about $100 per lens just for the K mount hardware) in order to preserve the value of the lens. Your dilemma is that the DSBs are good lenses, but don't command that kind of value, so spending an additional $100 per lens makes little economic sense. Rico, as he posted in the above link, has his patented dremel technique that shaves the C/Y mount itself, but its a destructive modification. I have no experience with the adapter, however I would trust Rico when he observes that the adapter magnifies the focal length. Since the registration distance between C/Y and K mounts is virtually identical, and the adapter has to add physical length, the focal length extension (i.e., acts as a type of extension tube stands to reason).

As a historical aside - Zeiss helped Pentax back in 1974/5 design and develop the K mount. The partnership broke up for whatever reason and Zeiss next went to Yashica looking for a Japanese manufacturing partner for their Contax cameras where they developed the C/Y mount (hence the name). The C/Y mount is essentially the K mount with the flanges a tad thicker, so that it's not physically compatible with the K mount. Its close but no cigar.

There is yet another novel approach, that I am searching for here. Some time back there was an interesting post from a student from Poland or the Czech Republic (if I remember correctly), that was in the process of developing an interesting approach. Adam then made a similar post on the forum's front page (that I am looking for). The approach was not swapping lens mounts but rather putting a new modified mount on the camera. The new mount maintained comparability with the K mount lenses, but also offered comparability with Olympus, Nikon's F, Konica's and Zeiss' C/Y mount lenses. Apparently each lens type rotated a bit off from normal so that the normal aperture up settings on the various lenses would have a rotational offset. This would involve unscrewing the current mount and putting on a new mount on the body which could be a straight forward operation. I found it...I have three lenses that I have swapped mounts on (Contax Zeiss 28/2.8 85/2.8 and a Leica 28/2.8). I also have another 2 lenses sitting on the bottom shelf that are C/Y (AS version as opposed to the MM version of the mount) that I can't swap mounts on, that came bundled with the Contax lenses that I modified. These 2 lenses a 135/2.8 and a 70-210/3.5 might be useful to be able to check out before I get around to selling them (I already have had them for a couple of years now).

So, where does that leave you? Pretty much where you are now, since the camera mount is not here yet. Given that low valuation of the DSB lenses, shaving the mounts may be the most cost effective route.

hope that helps some....


Last edited by interested_observer; 07-26-2013 at 03:11 AM.
07-26-2013, 04:31 AM   #5
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Do a "RioRico" chop job ... all you need is a Dremel, a bit tool and a bit of time ... J

Yashica 50mm f1.4 ML - "RioRico" modification to PK mount Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database
07-26-2013, 04:46 AM - 1 Like   #6
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PS - Forgot to mention that the same can be done to Prakticar mounts ... but, infinity is lost ...J

Carl Zeiss Jena - Prakticar 1.4/50 MC - Modified to PK fit Lens Reviews - Carl Zeiss Lenses - Pentax Lens Review Database

Prakticar Pentacon 135mm f2.8 MC Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database

Prakticar Pentacon MC 50mm f/1.8 Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database
07-26-2013, 04:46 AM   #7
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QuoteOriginally posted by stevebrot Quote
The adapter you linked to has a built-in optical element to support infinity focus. Conventional wisdom is that you should expect some decrease in optical performance as a result.


Steve
The simple optics in these types of adapters usually also work as a tele conveter, but the TC effect is usually small (~1.3x).
07-26-2013, 09:05 AM   #8
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QuoteOriginally posted by interested_observer Quote
So, where does that leave you? Pretty much where you are now, since the camera mount is not here yet. Given that low valuation of the DSB lenses, shaving the mounts may be the most cost effective route.
Thank you for the detailed analysis. As so many others have pointed out, it is the quality of the interactions with the other forum members that makes this site such a valued and useful one. As for your (and others) comments, yeah, these are not terribly expensive lenses, so I will try to modification and see how it works. I have been wanting a Dremel anyway for a while, so now seems like a good time.

BTW, while the ML50/1.9 has a lot of positive reviews and comments online, it does feel a bit light, with a plastic aperture ring, etc. The DSB 28/2/8 however, feels very solid with all metal construction and real heft to it. The 135/2.8 lies somewhere in between the two, but still feels pretty solid and is relatively compact (although bigger than a Pentax M135/3.5, but smaller than a Tak Bayonet 135/2.5, if i remember correctly...i am at work at the moment and don't have the lenses in front of me).

07-26-2013, 04:30 PM   #9
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I don't know if you would want to go in this direction but there are several C/Y adapters for M43 cams and I'm actually using one with a couple of Yashica ML's on my Olympus Pen. So far it's been good though DSB's are not quite as good IMHO as their ML counterparts. That's a large part of the reason I got the Oly though, to be able to use my Yashica lenses on a digital camera.
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