Mamiya 645 Pro - 135"W" back

If you've been following my PressPan thread you know that the reason I originally purchased it was to have a camera to shoot 35mm panoramas because:

• I sometimes like to shoot some 35mm film stock that's not available in 120 format
• I'm looking for a lighter alternative than the RB67 with adapters, or my GX617
• Not really interested in an X-Pan at the moment (not knocking it at all!)

Now that I've given up on the PressPan and sent it on its way to another owner, I can share a little of what I'm working on now as an alternative.

The Bronica ETRS has a 135W back available for it to shoot a 24mm x 54mm negative with the 35mm film spooled sideways so its oriented on the long side. This is in addition to the regular 135N back. I watched a youtube video recently where someone showed how easy it was to modify the N to the W and it made me wonder if I could do the same with the Mamiya 135 back since it is very similar to the Bronica version in terms of orientation and operation. I mean I could have just bought an ETRS set-up but I'd really like to avoid having another system of bodies and lenses and use something I already have.

I had 2 Mamiya 645 Pro/TL35mm backs sitting around so I took one apart and started modifying it. I cut out the film gate to widen it to 56mm, and then changed the position of the film roller/guide on the supply side, along with a few other small changes. I still have a few other things to work out, but have now shot 2 rolls thru it and am pleased with the results so far. I made a mask for the viewfinder to only show the 24mm x 56mm area that helps a lot with composition - similar to what I did for the RB67 as well when shooting pano's. The ability to shoot a roll of 35mm film AND rewind it afterwards is nice compared to shooting 35mm film in the RB67. It's not as wide, of course, as the RB solution but it makes for a smaller overall package, with the same things going for it like the RB solution such as modular backs and a good selection of sharp lenses. Although I'll probably only use the wider ones in the range. So far I've used the 35mm lens and the 50mm shift lens.

More on this to come.

Here's an example from the second roll, shot with the 35mm f/3.5 lens on FPP "Fine Grain Six" film (ISO 6) which I think is re-labeled Kodak 2238 film.

I had thought to do the same myself so I'd be very interested to see how you modified the 135 back, I have a 645 pro with the 35mm screen to go with the back so framing accurately shouldn't present too much of a problem.

Neil Morgan said:

I had thought to do the same myself so I'd be very interested to see how you modified the 135 back, I have a 645 pro with the 35mm screen to go with the back so framing accurately shouldn't present too much of a problem.

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It's a bit of a work-in-progress, and I'm not certain if I am going to make what I've done open-source, or open it up as a service for those who don't want to modify their own backs.

If you do a youtube search for modifying the Bronica ETRS 135N back into the 135W back, the video you'll find is the inspiration for what I did with the Mamiya back. The Mamiya back modification process differs in the fact that the roller that has to be moved doesn't have a pre-existing spot for it to go into, so some measuring and dremeling needs to be done to reposition it. And of course, cutting out the film gate.

One thing that still needs to be worked thru is the film advance. Just like the Bronica 135N back, the Mamiya 135 back has to use the work-around of firing the shutter again with the lens cover on and advancing again, otherwise there would be frame overlap. In practice this isn't as much of a pain as it sounds, unless you forget and don't do it. I had this same problem with that dreadful "PressPan" camera, in regards to forgetting to advance it twice. Not certain what the fix is for that. In theory I would have to either: A. Modify the gearing so that a full crank to stop moves it the necessary amount. Or B. Modify the stop so that it doesn't kick in until the crank moves it far enough so that its advanced properly.

Alternatively, the "C" option could be removing the stop all-together and just watching the numbers on the side of the back - ie - shoot shot #1, crank to #3 and then shoot the next. This isn't ideal as it would still waste film as the gap between shots doesn't need to be that large and personally I wouldn't like the idea of having to stare at those tiny numbers when cranking. I'd rather some sort of physical stop.

Hope that helps! Sorry for the ramble on.

Here's a few more images shot recently with the customized back. Shot in downtown Dayton, Ohio with Cinestill 50D film.



Jeremy

Jeremy Mudd said:

...unless you forget and don't do it.

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Heh... this is my whole life.

But for cameras, it's a small thing. If you're already doing a specialty thing I guess you just need to train yourself to do it as part of your process. Only took about a roll and a half before my double-stroke reflex kicked in when I got my leica, for instance, and a panoramic isn't usually something you want to fire a half dozen frames super quickly on.

Seems like what you've got going, even with this quirk, works great. Considering the fact that the W back on the Bronica is more expensive than the entire rest of a nice ETESI rig with a complement of nice lenses, and how nice the Mamiya lenses are in general, I see the value here. And I think you've done well. And your samples show you've done well! It's a pretty cool hack.

Moose22 said:

Heh... this is my whole life.

But for cameras, it's a small thing. If you're already doing a specialty thing I guess you just need to train yourself to do it as part of your process. Only took about a roll and a half before my double-stroke reflex kicked in when I got my leica, for instance, and a panoramic isn't usually something you want to fire a half dozen frames super quickly on.

Seems like what you've got going, even with this quirk, works great. Considering the fact that the W back on the Bronica is more expensive than the entire rest of a nice ETESI rig with a complement of nice lenses, and how nice the Mamiya lenses are in general, I see the value here. And I think you've done well. And your samples show you've done well! It's a pretty cool hack.

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Thanks! I enjoy tinkering with things.

When I watched the Bronica 135W back conversion video - my first inclination was to just buy an ETRS set-up and the 135W back, but then I visited eBay and saw the 135W back prices ---- and that idea went straight out the window.

And if I would have to hack a Bronica 135N back to work, then why not try the same with the Mamiya back that works the same way and is very close in design? The logic made sense to me, and right now Mamiya 135 backs are cheap, especially if you don't care about that stupid 12mm x 36mm "panoramic" dark slide and matching focusing screen. The backs without them are much cheaper.

Jeremy

Jeremy Mudd said:

It's a bit of a work-in-progress, and I'm not certain if I am going to make what I've done open-source, or open it up as a service for those who don't want to modify their own backs.

If you do a youtube search for modifying the Bronica ETRS 135N back into the 135W back, the video you'll find is the inspiration for what I did with the Mamiya back. The Mamiya back modification process differs in the fact that the roller that has to be moved doesn't have a pre-existing spot for it to go into, so some measuring and dremeling needs to be done to reposition it. And of course, cutting out the film gate.

One thing that still needs to be worked thru is the film advance. Just like the Bronica 135N back, the Mamiya 135 back has to use the work-around of firing the shutter again with the lens cover on and advancing again, otherwise there would be frame overlap. In practice this isn't as much of a pain as it sounds, unless you forget and don't do it. I had this same problem with that dreadful "PressPan" camera, in regards to forgetting to advance it twice. Not certain what the fix is for that. In theory I would have to either: A. Modify the gearing so that a full crank to stop moves it the necessary amount. Or B. Modify the stop so that it doesn't kick in until the crank moves it far enough so that its advanced properly.

Alternatively, the "C" option could be removing the stop all-together and just watching the numbers on the side of the back - ie - shoot shot #1, crank to #3 and then shoot the next. This isn't ideal as it would still waste film as the gap between shots doesn't need to be that large and personally I wouldn't like the idea of having to stare at those tiny numbers when cranking. I'd rather some sort of physical stop.

Hope that helps! Sorry for the ramble on.

Here's a few more images shot recently with the customized back. Shot in downtown Dayton, Ohio with Cinestill 50D film.

View attachment 295999 View attachment 296000 View attachment 296001 View attachment 296002 View attachment 296003

Jeremy

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Nice pictures, I'll take a look at my 135 back and see what I can come up with. I have the 135 adapter for my Mamiya 7ii already but I really like the format and versatility of the 645 so I think it will be worth persevering with.

Hi Jeremy,
I just ordered a 135 back as you did, and I'm very insterested in doing the same thing,
do you think you could post some pictures of the modifications you did?
Once you've done the modification, is it possible to set the mamiya on multilple exposure mode, and manualy advance the film to the good position (I'm thinking of counting the exact number of revolutions for an exposure, and placing a mark). I was thinking of the presspan too, but as I already have a mamiya, it's a lot of money, I find it easier that way. thanks for the inspiration, I once though I could do this with my other 135 back, but I didn't have the courage to do it! Now I definitely want to try!

juzzu said:

Hi Jeremy,
I just ordered a 135 back as you did, and I'm very insterested in doing the same thing,
do you think you could post some pictures of the modifications you did?
Once you've done the modification, is it possible to set the mamiya on multilple exposure mode, and manualy advance the film to the good position (I'm thinking of counting the exact number of revolutions for an exposure, and placing a mark). I was thinking of the presspan too, but as I already have a mamiya, it's a lot of money, I find it easier that way. thanks for the inspiration, I once though I could do this with my other 135 back, but I didn't have the courage to do it! Now I definitely want to try!

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Hi there,

In regards to additional information, please see post #3 above. As I stated before I'm not quite certain if I want to monetize this by offering this as a service, so I'm a bit hesitant to share all of what I've done so far. I will say that nearly all of the info is out there if you watch the Bronica 135W back conversion video on YouTube, and apply what was done to that to the Mamiya cartridge and film gate. If you are fairly handy and mechanical, you can figure it out.

I haven't tried to set it on multi-exposure and counting the revolutions. In theory that would work, although your numbers displayed on the back will become slightly off-count and you would need to keep track of exposure#'s some other way (ie, it might show you are in between #15 and #16 while you are actually on your 9th pano image). The ideal solution if I were to offer it turn-key would be to re-calibrate the amount of film it moves with each advance for the new frame width, which would probably involve a new part. And also re-labelling the counter so it matched the wider width frames and gave you the actual frame# that you were on. In practice, counting revolutions when advancing film can get problematic if a lot is going on. I've got marks on the advance wheel of the Holga 120N that I shoot 35mm film in, and while most of the time it works "OK", there are times when a lot is going on and having that be one more thing to keep track of can get annoying. Although, I guess, its probably just as bad to remember to shoot, cover the lens, shoot again, then take the next image.

If you don't mind, a few words on the PressPan. There is no way I'd recommend that camera purchase for anyone. It's right up there in the 5 worst photography purchases that I've ever made. Once I ordered and paid, the wait for the product was super long (I think 6 months IIRC), and the communication was non-existent. I get it that its not his first job and just a hobby, but a little communication would have went a long way and would have made the wait a little easier. Once it arrived I had to rebuild the light seals since that wasn't part of the initial purchase price (now its an "option"), and it suffered from some unknown light leak that I couldn't find that was somewhere between the 3D-printed lens cone and the body. Also I think the film plane distance was incorrect, as nothing was ever sharp at infinity, when the same lens on my Goodman Zone at infinity is tack sharp. There were other issues as well, including parallax which I never figured out - was probably due to the cold-shoe mount being not level. And the grip that supposedly held a spare roll of 35mm film but once you put the film in there it took tweezers and an act of God to get it back out again. It was a great-looking piece of equipment that people would stop and ask about when I was out shooting with it, but at the end of the day, results matter and I could not get acceptable images from it.

Jeremy

Hi Jeremy, have you given any further thought to making this open source ? I have a 645 Pro TL and am toying with the idea of adapting the 135 magazine however I don’t have the hand tools and it looks a bit risky to try without clear instructions.

If you are instead taking the idea commercial this might also be of interesting to me if you would like to repeat your endeavour I would like to purchase one.

Kind regards,

Rob.

asacrowflies said:

Hi Jeremy, have you given any further thought to making this open source ? I have a 645 Pro TL and am toying with the idea of adapting the 135 magazine however I don’t have the hand tools and it looks a bit risky to try without clear instructions.

If you are instead taking the idea commercial this might also be of interesting to me if you would like to repeat your endeavour I would like to purchase one.

Kind regards,

Rob.

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Sorry, I've been off Photrio for a while and am just now seeing this. Let me think about this and get back to you. I haven't picked up the 645 in awhile, and will probably get out and shoot a few rolls on it over the weekend in pano format. I installed a Rick Oleson screen earlier this year with the lines on it for the 35mm exposure area, which should help with overall screen brightness and also remove the need for the black plastic mask over the screen for composition purposes.

@Jeremy Mudd

As it's been a few years, I'm guessing you probably won't monetise this method? It would be great if you could share or private message me to see how you worked around the roller issue.

I've just purchased a 135 back which I'll start working on in the next week or so.

The other method I may do is the 120 modded back method, which I realise now will yield a lot more photos per roll vs the 135 panoramic edit.

Look forward to your reply. Cheers.

Darkroom_Drifter said:

@Jeremy Mudd

As it's been a few years, I'm guessing you probably won't monetise this method?

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I've been tweaking things over the last 8-9 months and have been shooting quite a bit with the 2nd version of the back.

While I would have liked to have had this buttoned up and ready for turnkey/conversions in early 2023, life and work has meant that progress has been slower than intended. Things sat dormant for a while until I picked it back up this past Summer.

Don't confuse my lack of updates here with stopping my efforts, and giving away my work for free.

Thanks,

Jeremy


Below is a recent shot from a fall trip to the Hocking Hills region in Ohio. Shot on the 135"W" version 2 back, on Kodak Ultramax 400 film.

Jeremy Mudd said:

Don't confuse my lack of updates here with stopping my efforts, and giving away my work for free.

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@Jeremy Mudd understable. I wanted to add a bit more context to my previous message.

I've recently acquired multiple 135 backs for the 645 and am fully prepared to delve into modifying these myself. Whether it works out on the first try or takes a few attempts (I DIY everything from full blown renovations to fidgety electronics, cameras etc... so I have an extensive arsenal of tools available).

I also wanted to let you know that once I've developed a reliable method, I plan to share it openly with the community at no cost.
Given that we're working with equipment from the '80s, I believe strongly in the value of supporting and helping each other within our small but passionate community.

For me It’s more about collective growth, helping others and keeping the enthusiasm for these classic systems thriving.

I truly appreciate any guidance you might offer and understand completely if you choose to keep your methods exclusive.
It’s important that your hard work and dedication are seen in the positive light they would deserve.

Thank you for considering this and I look forward to any insight you'd like to share.

I just got a135 back for my Mamiya 645 Pro TL with almost the sole intention to turn it into a 135W back. I found this thread and the results posted and then decided to buy it. After watching the YouTube videos on the Bronica 135 W conversion I noticed that the Mamiya 135 back doesnt already have another spot for the roller to slot into and the mask for the 135 cut out is part of the back, not the film holder. After holding it in my hands for a bit, I concluded that it is unlikely I could pull off this conversion myself without out some more specific guides or help from a crafty buddy and the 3D print files maybe.

Anyways, I made this account here to comment and say I'd really interested in this project and I'd love to see what @Darkroom_Drifter gets up to. There is room for two philosophies about this.

And thank you @Jeremy Mudd for starting this discussion and sharing your results. If you intend to offer this conversion as a service, I can understand not wanting to give up your techniques. Should we see some progress or a service offered for 135W back conversion in the coming months?

Does anyone know if the inserts for the backs for the M645 Super will fit into the original M645? And if so, will the 35mm insert fit?
Thank you

coronet3d said:

Does anyone know if the inserts for the backs for the M645 Super will fit into the original M645? And if so, will the 35mm insert fit?
Thank you

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Yes to the first question.
I can't answer the second question.

coronet3d said:

Does anyone know if the inserts for the backs for the M645 Super will fit into the original M645? And if so, will the 35mm insert fit?
Thank you

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The 120/220 inserts are the same between 645 and Super as Matt said. I've never had a Mamiya 135 back, but just from looking at pictures, both the inside of the 135 back and the insert are completely different from the 120/220 inserts. There's no way. It is not surprising since among other things, the 135 film has to be transported in the perpendicular direction to the 120.

@Jeremy Mudd Hope you will release this as I am totally in for a purchase as my Budget will not allow an Xpan, this will do lovely ;-) !