Adapt Copal shutter to Mamiya 645?

[binglebugbob]

Does anyone know of a reasonably simple way to adapt a Copal zero or Copal 1 shutter to a Mamiya 645?

I suspect you'd have to use extension tubes and a focusing helical, or maybe a bellows to use, say, a 200mm focal length view camera lens on the Mamiya.

I couldn't find a copal thread to Mamiya 645 bayonet listed on the auction site....

 

[wiltw]

• Mamiya 645 has its own focal plane shutter. So, to take a photo the focal plane shutter has to be opened, which forces the need for the mirror to also be lifted out of the way to make a light path from lens shutter to film.
• So you aim and focus, then release shutter on B to lift refllex mirror and open light path to focal plane, THEN you would open the Copal shutter using its shutter release.
• If you mounted a Large Format 200 lens on an extension tube that has a M645 mount to attach to the body, you would need a means of altering the lens distance from focal plane (the bellows) in order to focus. And need to figure out how to mount the lens so that light does not pass into the inside (except thru the optics) The mounting of the LF lens on usual mounting plate, then afix the plate to the front of the bellows, using black epocy seems conceptually easy. The hard part is the mecahnical fit of rear of LF lens into the bellows opening and the extension tube diameter (vs. the size of the rear element of the LF lens)!

(I have used a sacrificial extension tube to mount my Bronica to a rear plate of a Horsemen monorail, using black epoxy...the LF lens on MF body is simply the same concept, but with the fit of the LF lens rear optic being the primary issue.)n I just checked and the OD of my Computar 210mm lens does fit within the ID of the Bronica lens mount.

 

[Light Capture]

It's relatively simple. All parts are available. It might take some experimentation to determine what flange distance is needed for helicoid and extension.
I place the lens in front of the camera and measure roughly. That's enough most of the time when different extension tubes are available. When I need precise measurements, that's done in different way.
If copal mounted lens is mounted on LF camera, measurements can be taken precisely while mounted on LF camera.

1. You will need focusing helicoid in either M52 or M65 size. M65 is better. Leaves you around 60mm clearance for rear element. There are a couple of different extensions.
2. Mount adapter from M65 to Mamiya 645. There are only two sellers on eBay with this adapter at the moment.
3. M65 copal adapter for #0 or #1. There are few on Ebay
4. Mamiya 645 tubes to be able to place a lens to needed flange focal distance. It would work in combination with the amount of helicoid extension

 

[wiltw]

Keep in mind that due to the large image circle of the LF lens, its delivered detail resoution (line-pairs per millimeter on film) is a fraction of what the Medium Format lens delivers. So while you do get an image on film, its resolution is fundamentally limited, and likely to be disappointing, compared to using medium format lens of same FL.

 

[John Koehrer]

It's relatively simple. All parts are available. It might take some experimentation to determine what flange distance is needed for helicoid and extension.
I place the lens in front of the camera and measure roughly. That's enough most of the time when different extension tubes are available. When I need precise measurements, that's done in different way.
If copal mounted lens is mounted on LF camera, measurements can be taken precisely while mounted on LF camera.

1. You will need focusing helicoid in either M52 or M65 size. M65 is better. Leaves you around 60mm clearance for rear element. There are a couple of different extensions.
2. Mount adapter from M65 to Mamiya 645. There are only two sellers on eBay with this adapter at the moment.
3. M65 copal adapter for #0 or #1. There are few on Ebay
4. Mamiya 645 tubes to be able to place a lens to needed flange focal distance. It would work in combination with the amount of helicoid extension

What he said.^^

When I was young I adapted a 135 Tressar to a Nikon body using an inexpensive F mount bellows(Accura, etc).
Jury rigged the Tessar to the front of the bellows & was able to get infinity+ very close focus.
Doesn't help w/645 but the idea's the same.

 

[abruzzi]

if you have a lot of spare cash, this might get you there with a minimum of superglue and JB Weld:

https://www.ebay.com/itm/203838512934

 

[binglebugbob]

I'm more the "starving artist" type. But it looks like it would work.

 

[abruzzi]

me too. Its way too righ for my blood, but having got into LF photography, I noticed that a lot of manufacturers (Arca Swiss, Linhif, Cambo, Plaubel) recently got into setups to mount a digital camera on the rear standard. Other focused on digital backs. Since there was a digital version of the Mamiya 645, I figued there was a good changes someone made something.

the next best things would be a macro bellows for the M645. It would still require some fabrication on the lens mount since the macro bellows will generally be designed for a standard M645 lens in the front. Its cheaper, but not cheap:

https://www.ebay.com/itm/265552462562