CONTAX 645 - which lens do/did you like best?

[darylgo]

Thanks for all the info! I am intrigued about the "rare Mamiya lens to Contax body adapter" - I imagine this was a Zoerk creation? But given that the Contax registration distance is 64mm vs. the Mamiya's 63mm (someone recently posted the Contax value, thanks), wouldn't that mean that the lenses could not focus to infinity?

The Zoerk adapter is no longer made, I have been looking for well over a year and none has surfaced.  Lloyd Chambers of diglloyd.com says the Zoerk adapter was "crappy".  I am not sure what aspect of the adapter he was less than impressed with...materials, workmanship, etc.  Finding one at least offers a template.  Car enthusiasts often machine parts and a good friend told me that it wouldn't be impossible to machine this adapter.  I never pursued it.  I purchased an aluminum adapter (not Zoerk) last year on ebay, the seller said he had it custom machined.  The adapter I have works perfectly, it is very thin and all my Mamiya lenses focus to infinity, therefore Contax flange to film distance is shorter than Mamiya.  The Mamiya flange distance is 63.3mm.  Contax?  Prior to finding the adapter I had been talking to Adam at SK Grimes, skgrimes.com, and he indicated they could either change the Mamiya mount to Contax or make an adapter, I would need to send body and lens to them, the approximate cost would be $500.00....if it could be done.   Once the lens mount is changed it might not be possible to change it back.  The adapter made this whole process unnecessary.  Since this discussion started with lenses I will tell you my impressions of Mamiya lenses vs. Contax in controlled tests.  Mamiya lenses are generally as sharp as Zeiss lenses, the richness of color of Mamiya is poor compared to the brilliant Zeiss rendering.  Photoshop is the great equalizer and the Mamiya lens images can be made to look Zeiss-like without too much effort.  I would not give up my  Mamiya lenses but Zeiss is more pleasing to my eye.    

[ondebanks]

Hmmm...so the Contax flange distance is shorter than the Mamiya's. That completely inverts the impression I'd been given in the other thread. I wish people wouldn't toss out values that they are uncertain of.

That inversion is planting dangerous ideas in my head...I could keep my M645 lenses and switch to a Contax body with a WLF...no, no, Ray - stop it. You only just got your AFD + DCS645M back a few months ago!

[cyberean]

Hmmm...so the Contax flange distance is shorter than the Mamiya's.

according to Zeiss, the Contax 645 register/flange distance is 64mm

[revaaron]

I shot a bunch of stars tonight with the 45mm.

[darylgo]

according to Zeiss, the Contax 645 register/flange distance is 64mm

After a quick search of the internet for Contax 645 info I found it is extremely scarce.  Many websites list the Mamiya as 63.3mm.
I did some crude measurements of the Contax body and it repeatedly measures 59mm, but wait, there's more.  The film or sensor doesn't sit flush with the back mounting flange of the camera,  it sits back 2-3mm (best guess using unsophisticated eyeball technique).  Okay, here's where it gets fun, the Mamiya adapter is 4mm+, which roughly results in 63+mm of the Mamiya (59+4=63), but if you add the extra 2-3mm for the setback of sensor or film this adapter should not work.....but alas it does.  A quick call to Contax and discussion with a tech rep should clear this up but sadly they are all gone, if anyone has some experience with this I will gladly defer to their expertise.   

[Tomas Johanson]

A quick call to Contax and discussion with a tech rep should clear this up but sadly they are all gone, if anyone has some experience with this I will gladly defer to their expertise.   

Here are some numbers from the Repair Manual.

[cyberean]

according to Zeiss, the Contax 645 register/flange distance is 64mm

After a quick search of the internet for Contax 645 info I found it is extremely scarce. 

i'll give you a hint ... "according to Zeiss".
Zeiss may also know something about the register specification.

[ondebanks]

Thanks for all these numbers and scans, guys.

OK:
- Zeiss says 64 mm
- Contax repair manual says 59.80mm + 4.35mm = 64.15 mm (right?);  same ballpark but not the same.
But:
- Darylgo says his Mamiya adapter is 4mm+ thick; so 64mm (body) + 4mm (adapter) = 68mm...and yet his Mamiya lenses (63.3mm) do focus to infinity on this adapter
- I found the Zoerk link (http://www.zoerk.com/pages/p_mounta.htm) which backs up Darylgo: "We also offer a unique Mamiya 645 to Contax 645 cross-platform adapter. This adapter allows the use of Mamiya lenses on the Contax 645 with the full focusing range from infinity to close up."

It doesn't add up. 

Could it be that the "throat" of the Contax is wide enough to allow the Mamiya lenses be recessed a few mm into the adapter? I'm clutching at straws to make the maths work.

[cyberean]

- Zeiss says 64 mm

Zeiss quotes its number relative to the film plane.

- Contax repair manual says 59.80mm + 4.35mm = 64.15 mm (right?);  same ballpark but not the same.

you forgot to account for film ... ~ .11/.12mm

But:
- Darylgo says his Mamiya adapter is 4mm+ thick; so 64mm (body) + 4mm (adapter) = 68mm...and yet his Mamiya lenses (63.3mm) do focus to infinity on this adapter
- I found the Zoerk link (http://www.zoerk.com/pages/p_mounta.htm) which backs up Darylgo: "We also offer a unique Mamiya 645 to Contax 645 cross-platform adapter. This adapter allows the use of Mamiya lenses on the Contax 645 with the full focusing range from infinity to close up."

It doesn't add up. 

Could it be that the "throat" of the Contax is wide enough to allow the Mamiya lenses be recessed a few mm into the adapter? I'm clutching at straws to make the maths work.

all along the assumption for the M645 has been 63.3mm.
is that even accurate?

[ondebanks]

Zeiss quotes its number relative to the film plane.
you forgot to account for film ... ~ .11/.12mm

I don't think so; check the Contax repair manual scan again. I used the distance to the inner film rail, and omitted the extra 0.4mm to the pressure plate. The film (and its backing paper) would occupy that extra 0.4mm space. Accounting for film thickness would actually add ~ .11/.12mm to the 64.15 mm value, making 64.27mm or so.

So we still have a discrepancy.

all along the assumption for the M645 has been 63.3mm.
is that even accurate?

Perhaps not! It's a value I've seen quoted everywhere for years, but I would like to verify it from at least one original Mamiya source.
I have a Mamiya 645 1000s repair manual...maybe that will mention it.

Ray

[cyberean]

I don't think so; check the Contax repair manual scan again. I used the distance to the inner film rail, and omitted the extra 0.4mm to the pressure plate. The film (and its backing paper) would occupy that extra 0.4mm space. Accounting for film thickness would actually add ~ .11/.12mm to the 64.15 mm value, making 64.27mm or so.

yup, i was referencing the wrong set of rails and got the film orientation reversed.
(... that's what happens when i review specs before my AM coffee)
so, what we're potentially accounting for is just the thickness of the emulsion layer ~ .015mm or so.

Perhaps not! It's a value I've seen quoted everywhere for years, but I would like to verify it from at least one original Mamiya source.
I have a Mamiya 645 1000s repair manual...maybe that will mention it.

and i did come across what appears to be a Mamiya service manual, that has the flange to film-surface distance at 63mm
(... and 63.3mm to outer film guide rail)

[darylgo]

Could it be that the "throat" of the Contax is wide enough to allow the Mamiya lenses be recessed a few mm into the adapter? I'm clutching at straws to make the maths work.

Problem solved...maybe.  ondebanks hit the nail on the head, the Contax throat is wide enough to recess the Mamiya 645 lens.
And in fact the adapter is 4mm thick but the back mount of the Mamiya lens does not sit on the extended portion of the adapter.  It recesses into the adapter and sits anywhere from 1/2mm to 1 1/2mm recessed into the lens.  These are indirect measurements as direct measurements require more sophisticated tools than a fairly accurate mm ruler.  At this point we know that the Contax is 64mm, maybe 64.15mm, we also know that Mamiya is 63.3mm.  The recess would have to be .7 to .85mm which is consistent with the measurements of the adapter.   Thanks everyone for going through this mental excercise!

[tho_mas]

just got the 45-90mm zoom lens.
It's quite heavy and bulky and it's "only" f4.5 ... but this is an impressive lens!
First impressions (in conjunction with a P45):
It's very sharp at all focal lengths wide open in the center and not bad at all the edges.
At 45mm you have to stop down to f8 to get sharp edges, from 55mm upwards the edges are really good at f5.6.
It shows less distortion than I thought it would (at 45mm and 55mm complex/moustache barrel distortion, similar to the 2.8/45, at 70mm literally distortion free, at 80mm and 90mm slight pincushion distortion - but I think you will notice distortion at any focal length only when shooting architecture or stuff where distortion shows up very clearly).
It also shows very little CAs.
Actually I was looking for a replacement for my 2.8/45 that was quite a weak copy (even stopped down not really sharp at the edges and heavy CAs). Well, now I have a new 45mm and a bit more...
Nice lens!