[2351HD]

Hello all,

Does anyone know which mounts the registration distance of full frame Pentax allows us to convert? For example, I can convert Nikon mount lenses to run on a Canon, but not vice versa.

Most of the info. I can find about adaptors refer to the Pentax crop mount, which of course will not work the same way.

So will I be able to use Nikon mount lenses on the K1 with an adaptor? What about Contax/Yaschica mount? Obviously I mean while retaining infinity focus (and without the adaptor requiring optical elements).\

Thanks everyone!

Ed

Ed I believe that Leitax soon will have a Nikon to K mount conversion kit available for the Zeiss ZF and ZF.2/Milvus lenses to work on the K1. See Diglloyd.com blog

[pde2000]

This isn't really true. Asahi basically looted the Pentax name from Zeiss Ikon after the Pentax trademark belonging to Zeiss Ikon ("Pentaprism Contax)e was annulled following WWII. The C/Y mount was developed independently by Carl Zeiss (West Germany) in collaboration with Yashica Kyocera, who revived the Contax name in the West in 1975 (the earlier Contax rangefinders were made by Zeiss Ikon East Germany). Asahi Pentax was uninvolved, other than providing some expertise on coatings which was incorporated into the T* Zeiss lenses. The adaptability is purely coincidental and stems merely from similar flange focal distance in the two.

Thanks for correcting me, must have read the info somewhere, but it was wrong. The other similarity between contax and pentax is their reverse compatibility with m42, just using a zero thickness ring. The advantage of the contax mount is the lock being on the side, so you can either leave the ring on the lens, or in the mount, without having to fiddle with a little spring. This similarity accounts for the similar registration distance, but there are those little differences that make life difficult. If you dont mind manual focus and aperture the contax zeiss lenses are a treat.

FYI the collaboration of businesses across the globe was good for everyone; Western electric helped start businesses in england, europe, and japan which still manufacture telecommunication and audio today.

edit; I found that for a year prior to partnering with Yashica, zeiss (west) were collaborating with pentax, with some lens designs, advancing the smc formula (zeiss invented coating), and producing the K mount for Asahi. So it's no wonder the c/y mount is so similar - the differences are just there to prevent easy cross purposing. It is disputed as to whether Asahi purchased the name pentax, or took it from zeiss (east). Certainly Contax was the first brand of camera to use the m42 thread, with it's pentaprism reflex camera S(1949).

Schneider's partnering with Samsung, and previously Kodak was mostly about their expertise in computing lens design and QC, rather than manufacturing, but it is likely most lens manufacturers are dependent on such expertise - the 18-55 kit lens seems consistently familiar across most brands.

[pde2000]

I found this interesting site; CONTAX CLUB Carl Zeiss ??? ? ???? - C/Y lens on Pentax DSLR showing how to shave the mount, rather than the lens. This allows the contax lenses to be used unmodified, and keeps the natural functioning for pentax lenses. After removing the fraction of a mm from the back of the mount from 3 places, and snipping out the m42 retaining spring (care not to break the ground wire) the contax lenses can be mounted with all 3 bayonets engaging by rotating anticlockwise. The 0.3mm difference in depth of the inner ring prevents most lenses from achieving infinity, and i wouldn't be happy to follow the instructions to remove some of the plastic of the camera body. Another nice thing is that the stopdown lever wont foul so there is no need to cut the lever off (the c/y stopdown lever does operate the same way as the PK but they are not compatible).

Another option is to buy a ready made universal mount from these guys; Pentax K+ Multi-Mount (WR version) - Adaptist otherwise the inner ring of the mount needs to have 0.3mm shaved off, which is not a little job, like the filing of the backside.

The vario-sonnar 80-200 doesn't seem to be affected by this 0.3mm registration error, but maybe would be even sharper when mounted at the correct distance. The m42 registration distance of 45.5mm is consistent between pentax and contax, but they position the bayonets at this slightly different depth.

[pde2000]

Well i must confess that the modification of the camera was more daunting than the lenses, but having done the Kx first (takes a good picture but not worth much) I felt much more confident to then do the K01. Now I would prefer to modify the camera and leave the lenses unmodified, but the 0.3mm error remains. Old contax lenses can have their helicoid adjusted and there is no leitax or equivalent possible for them. I just got a 28/2.8 distagon aej for £130 because it cannot be converted.

Having used the manual lenses with digital bodies I cant see any going back - the 40xs is a pretty good lens but the kit zooms are just toys really. The contax lenses outresolve the sensor.

[Dlanor Sekao]

Adaptist makes a mount replacement for pentax dslr cameras that might interest you.

Adaptist - Home

Hehehe !........Not too many Know....Shhhhhhh....

[boriscleto]

I wish Adaptist still made the non-WR mount. I was going to mod a K-x but waited too long...

[pde2000]

Well having modified the camera mount I have been able to check my other vario-sonnar 80-200 that was untouched, and it is much softer with no real pop or focus at infinity. Hopefully that just means the first copy I got was misaligned in my favour and the newer one will need the leitax conversion to remove registration error, certainly the one i have been using the past few years gives a razor sharp image. I only got the backup because it's hard to resist a bargain.

Might be worth getting a WR adaptist mount now, while they are still available, in anticipation of getting a K1. Does anyone have any experience of this product; hitting infinity etc?

The distagon 28/2.8 arrived and was easy to adjust - the filter ring screws off, so the front cell stays put, and 3 little screws need loosening so the focus ring can be rotated a little bit and locked at the new infinity point. I actually took the focus ring off completely so i could check the infinity point, then put it back at the new position before replacing the locking ring and screwing it back down.

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Last edited by pde2000; 06-17-2016 at 05:29 AM. Reason: new lens arrived.