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08-02-2013, 10:57 AM   #1
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Adapting Mamiya LS lenses to Pentax

Does anyone have any experience adapting any of the older or newer Mamiya LS lenses to work with a 645D? I'm particularly interested in adapting the Mamiya 55 LS to Pentax to be able to sync at 1/500th.

Bob Croslin

08-04-2013, 01:12 AM   #2
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Hi Bob,

I am pretty sure that the difference in the registration distances of the two systems means that the Mamiya lenses cannot be adapted to fit the Pentax system (at least without losing infinity focus or requiring quality-sapping optics to adjust for this) - which is why, unless I am mistaken, you will not find any such adaptors. If I am wrong about this, by the way, I would love to know about it! :-)

The other issue with the newest LS lenses is that I think they have electronics within them to control the shutter, which of course would require a very clever adaptor to allow their use on another camera system (this sort of adaptor is very rare, even when registration distances allow them to exist).

Ed
08-04-2013, 01:16 AM   #3
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One correction in my second paragraph - I meant "aperture" not "shutter" - though come to think of it that may be true too!
08-04-2013, 05:50 AM   #4
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I think a simple non optical correcting adaptor is not possible because the Mamiya 645 register is 63.3 mm while the Pentax 645 is 70.87 mm
I did not see a 55mm LS lens listed in the Mamiya RB and RZ series both of which should be adaptable to Pentax 645 by their longer registers ( 112 mm and 105 mm respectively).

I suppose you want a wider lens than the P67 90 LS?

I am interested because last night I took my first flash with the AF360fgz flash coupled to the Tak 6X7 90 LS.
That flash has inbuilt settings for the P67 lenses and I want to run a roll at different settings and f/ etc

08-04-2013, 03:23 PM   #5
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Thanks for the answers. I'm trying to adapt a wider Mamiya LS lens to a Pentax 645D. Anyone had any luck adapting the new Mamiya/ Phase/ Schneider LS lenses to the Pentax 645D? The 55 LS 2.8 would be incredible on the 645D.
08-04-2013, 03:26 PM   #6
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The RB and RZ lenses are all, I think, leaf shutter. The problem with those is a different one - the lenses don't focus within themselves, as the system uses a bellows to focus. So adapting the lenses (even supposing you could find an adaptor to do so) would not allow you to focus the lenses. You would need an adaptor to have a helicoid or similar within it before you could focus the lenses. I do recall hearing a while ago of an adaptor being lanched that does exactly that by the way!
08-04-2013, 04:02 PM   #7
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I think the answers above answer your question that it cannot be done
08-04-2013, 06:15 PM   #8
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Thanks Ed

08-04-2013, 10:55 PM   #9
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Just to clarify, I meant that adapting the Mamiya 645 lenses to use on a Pentax - without some sort of adaptor containing optics - is impossible.

However, if you are interested in the use of the RZ/RB lenses on a Pentax, including the complex adaptor that includes a helicoid, take a look at this link; this one is to adapt the lenses for use on the Mamiya 645 mount, but apparently they also exist for the Pentax 645 mount:
http://www.photoscala.de/Artikel/HCa...-Phase-One-645
http://www.pressebox.de/pressemeldun...e/boxid/430179

You might also find reading this thread useful - there is quite a bit of discussion of the adaptor:
Mount adaptors with helicoid for RB/RZ lenses - The GetDPI Photography Forums

Ed
08-05-2013, 05:42 AM   #10
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Thanks Ed. I'm trying to find an LS lens for my 645D that is wider than a 75mm. The only downside I've found with my 645D is the 1/125th flash sync and the LS lenses overcome that.
08-05-2013, 03:13 PM   #11
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Hello Bob,


You might want to check these guys.... They do exactly what you are looking for.


HCAM RB/RZ-645 Adapter

"...Use Mamiya RB/RZ lenses on 645 and 35mm Bodies
Many of the excellent high quality Mamiya RB/RZ medium format lenses are owned respectively available worldwide for reasonable prices. A lot of professional and amateur photographers had/have such systems in use. So, it was obvious, to present a solution for the adaptation of these excellent lenses for the Mamiya 645(D) ,the Pentax 645D, Contax 645 AF and all of the well known 35mm (D)SLR camera systems (digital or analogue). The smaller camera formats use the optical sweetspot of the RB/RZ lenses, resulting in best sharpness and contrast, even illumination and the absence of chromatic aberration. Many of the special RB/RZ lenses, like the portrait soft M 150mm and 180mm lenses, the legendary Apo telephoto lenses, or the outstanding 140mm macro lens, are perfect for professional usage.
The HCam RB/RZ adapter is a cooperation product of Stefan Steib/Munich ( Sales & Marketing ), and WIESE-Fototechnik/Hamburg (Technical & Production )..."
08-06-2013, 12:55 AM   #12
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Yep - that's the one. We're vigorously agreeing on this - that's the same adaptor linked to above :-)
08-06-2013, 02:19 PM   #13
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With the adapter though I don't think the 645D will recognize it as a leaf shutter lens. So the mirror and in body shutter won't function like they would with the Pentax LS lens. It is going to treat it like a completely manual lens and not know it has a leaf shutter.

Two possible thoughts on making it work correct.

One which is a guarantee is to put the camera in bulb then trigger the leaf shutter then release the bulb. Problem is potential noise from exposing a picture longer than needed, and if you take over a 30sec shot on the bulb it will do a dark frame. Wouldn't have been a problem in the days of film, but...

Or rip apart a Pentax 645 LS lens. The pins are probably sending some kind of signal to the camera that it is LS. Could see if Hartblei could use this 645 mount with the pins and electronic chip (or whatever is in there) when they assemble the adapter. Would make cost go up a lot I bet. But would allow the RB lenses to function exactly like Pentax 75mm leaf shutter lens...

Would also have to confirm that the RZ and RB lenses don't require any electronics...

Just my thought, although I have never tried my leaf shutter lens on the 645D to know if it works the same as on the film bodies. Never needed it as I don't do flash work anymore. If you work out the second option though I would probably be a buyer.

Edit:
RB lenses look to be fine with no electronics; widest I see is 50mm. RZ lenses have some electronic pins and from looking at a couple I don't think you will be able to change the shutter speed without a RZ body. Would need to investigate the RZ more but it appears as though the only option for using leaf shutter would only be with the RB lenses via one of the two options posted above...

Last edited by atlnq9; 08-06-2013 at 02:43 PM.
08-06-2013, 03:16 PM   #14
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Actually looking at my 75mm LS lens now the second option won't work. The shutter on the 645 lens is triggered from the camera not from a cable remote. Only option looks like the first option of starting an exposure in bulb then triggering the shutter in the Mamiya lens with cable remote then releasing bulb. With practice it could become efficient. Would have to be working from a tripod though because you need both hands. That though is assuming the Mamiya lens sends a signal out the PC cord without any electrical input. Easy to test if you found somebody with an RB lens to test, just trigger the shutter with the lens not mounted and see if the flash fires. Or get a Hassy, Phase One, or Leica medium format kit...

With enough money investment you might be able to get all the electronics to work together but would probably cost more than a new system.
08-12-2013, 01:50 PM   #15
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QuoteOriginally posted by atlnq9 Quote
Or rip apart a Pentax 645 LS lens. The pins are probably sending some kind of signal to the camera that it is LS. Could see if Hartblei could use this 645 mount with the pins and electronic chip (or whatever is in there) when they assemble the adapter. Would make cost go up a lot I bet. But would allow the RB lenses to function exactly like Pentax 75mm leaf shutter lens...
There is no "signal", Pentax LS lenses are completely mechanical. The shutter actuation is tied into the aperture stop-down lever. When the camera stops down, the leaf shutter blades close, the main shutter opens, after a fixed delay the leaf shutter reopens for its exposure, the leaf shutter closes, and the main shutter closes after its exposure time has been complete. Depending on the precise model the leaf shutter may or may not reopen until you cock it again (the 6x7 90 LS reopens, the 6x7 165 LS supposedly doesn't).

The camera knows nothing about when the leaf shutter opens and closes and in fact doesn't even know there's a second shutter in the lens. You must set the FP shutter to open for longer than the leaf shutter (at least 1/8th second) or else you will cut the exposure short, and the metering is based on the camera setting, not the lens setting.

It might be possible to create an adapter that would simply hold a Mamiya 7 lens open, assuming you had adequate register distance and all that other jazz. Essentially what you are suggesting is a permanent bulb exposure, you might be able to attach the contacts to a logic analyzer, trigger a bulb exposure, and then build an adapter that just sends that signal without closing it. It would probably require power continuously to hold the aperture open.

Last edited by Paul MaudDib; 08-12-2013 at 02:16 PM.
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