35mm Zeiss Contax lenses on 645?

atlnq9 · 12-25-2011, 12:14 AM

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Do these guys know what they are talking about?

Modifying a Zeiss T* C/Y Tele-Apotessar 300mm 2.8 to work on Pentax 645? They only say 645D but is the image circle large enough even then for the cropped 645? To do this they must taking a serious chunk off the lens mount to make the registration distance work. I find it hard to believe.

Contax Tele-Apotessar T* 300mm f/2.8 APO to Hasselblad 200/Leica S2/Pentax 645D | eBay

eddie1960 · 12-30-2011, 02:08 PM

why would you butcher a beautiful piece of glass like that to fit medium format (likely with reduced results as well
adapting to apsc/35mm i can see but the medium format idea is just dumb
but for this one Leitax hasn't even made an adaptor for this mode for any camera

I could see it being possible to adapt the Contax 645 lenses perhaps

Yamanobori · 12-30-2011, 05:28 PM

If a Leica 400mm R series telephoto can work on an S2, I can't see why a Contax telephoto can't work on a 645D:

Red Dot Forum - Testing the Leica 400mm APO-Telyt-Modular-R on the Leica S2

stevebrot · 12-31-2011, 03:44 PM

Originally posted by Yamanobori

If a Leica 400mm R series telephoto can work on an S2, I can't see why a Contax telephoto can't work on a 645D:

Red Dot Forum - Testing the Leica 400mm APO-Telyt-Modular-R on the Leica S2

It is all a matter of registration distance, mirror clearance, and useable image circle. Assuming you can shave the mount the rear element is where it is. The mirror for the 645D is much shorter than for a 645, so this may be doable...assuming that you can machine the lens down enough to allow for infinity focus. (70.87mm - 45.5mm --> 25.37mm to shave!!!) Then there is the issue of vignette.

All of these factors are noted in the article you linked. Whether the same can be done for C/Y to 645D is high dependent on the lens.

Steve

Yamanobori · 01-01-2012, 07:58 AM

Steve, I was just showing there is precedent. The seller believes it can be converted, so I assume they have done the homework.

12-25-2011, 12:14 AM	#1
atlnq9 Veteran Member Join Date: Mar 2011 Location: Arizona Photos: Albums Posts: 330	35mm Zeiss Contax lenses on 645? Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Do these guys know what they are talking about? Modifying a Zeiss T* C/Y Tele-Apotessar 300mm 2.8 to work on Pentax 645? They only say 645D but is the image circle large enough even then for the cropped 645? To do this they must taking a serious chunk off the lens mount to make the registration distance work. I find it hard to believe. Contax Tele-Apotessar T* 300mm f/2.8 APO to Hasselblad 200/Leica S2/Pentax 645D \| eBay

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12-30-2011, 02:08 PM	#2
eddie1960 Veteran Member Join Date: Aug 2010 Location: Toronto Photos: Gallery \| Albums Posts: 13,666	why would you butcher a beautiful piece of glass like that to fit medium format (likely with reduced results as well adapting to apsc/35mm i can see but the medium format idea is just dumb but for this one Leitax hasn't even made an adaptor for this mode for any camera I could see it being possible to adapt the Contax 645 lenses perhaps

12-30-2011, 05:28 PM	#3
Yamanobori Veteran Member Join Date: Feb 2011 Photos: Gallery Posts: 573	If a Leica 400mm R series telephoto can work on an S2, I can't see why a Contax telephoto can't work on a 645D: Red Dot Forum - Testing the Leica 400mm APO-Telyt-Modular-R on the Leica S2

12-31-2011, 03:44 PM	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Yamanobori If a Leica 400mm R series telephoto can work on an S2, I can't see why a Contax telephoto can't work on a 645D: Red Dot Forum - Testing the Leica 400mm APO-Telyt-Modular-R on the Leica S2 It is all a matter of registration distance, mirror clearance, and useable image circle. Assuming you can shave the mount the rear element is where it is. The mirror for the 645D is much shorter than for a 645, so this may be doable...assuming that you can machine the lens down enough to allow for infinity focus. (70.87mm - 45.5mm --> 25.37mm to shave!!!) Then there is the issue of vignette. All of these factors are noted in the article you linked. Whether the same can be done for C/Y to 645D is high dependent on the lens. Steve

01-01-2012, 07:58 AM	#5
Yamanobori Veteran Member Join Date: Feb 2011 Photos: Gallery Posts: 573	Steve, I was just showing there is precedent. The seller believes it can be converted, so I assume they have done the homework.