Question about Mamiya 645 Pro insert compatibility

[Woudschim]

Greetings,

I own a Mamiya 645-pro. I've got a good few rolls of 220 films in the fridge which I used in my Bronica S2a, which I recently sold.

I am now only able to use 120 film, for I only have a back with insert for 120-film.

I have an option to buy an 220 insert from a Mamiya M-645, but will it be usable in the 645-Pro backs? I seem to recall that all the inserts where interchangable troughout all the 645 models, but I'm not 100% sure.

Does anybody know for sure whether or not I can use a M-645 220 insert in a Mamiya pro back?

Thanks!

 

[Greg_E]

The insert will fit, but I'm not certain it will function properly because I have never owned any 220 inserts or backs. In the cameras without a removable back (1000s, etc.) it is said to work, so it should work in the pro back but it is kind of a guess.

 

[chriscrawfordphoto]

Yes it will function properly. All the Mamiya 645 models used the same interchangeable inserts. The backs for the 645 super and 645 pro can use either the 120 or 220 insert. It functions as a 120 back with the 120 insert, and the 220 insert changes the frame counter to work for 220! I always thought that was cool. The insert is a lot cheaper than a full back, which makes using 220 film much cheaper on Mamiya 645 than on other medium format cameras that require a full back for 220.

 

[MattKing]

What Chris says!

One caution though - this applies only to the manual focus Mamiya 645 cameras. The autofocus Mamiya 645 cameras use entirely different inserts and backs.

If you see an auction for a manual focus Mamiya 645 "220 back" it is just a back with a removable 220 insert, and either a 120 or a 220 insert will work fine in it.

One of the tricks I learned fairly early on was that if someone is selling a "220 back" for the Mamiya 645s that use interchangeable backs (the Super, the Pro or ProTl) you can probably buy it and a separate 120 insert for less than a back that comes with a 120 insert.

Matt

 

[mawz]

Note the interchangeability only applies to 120 and 220 inserts in 120 and 220 backs (the backs are identical). The 645 Super/Pro/ProTL also offer 35mm and Polaroid backs which are not inter-compatible.

 

[Woudschim]

Thanks for the replies!
There will be a package containing a 220 insert coming this way very soon.

 

[Cholentpot]

What a way to revive a old thread...

I have an M645 (Not a J, Pro, or Super. The original) and would like to use a 135 insert. Would one of those work in my machine?

 

[macfred]

What a way to revive a old thread...

I have an M645 (Not a J, Pro, or Super. The original) and would like to use a 135 insert. Would one of those work in my machine?

As far as I know the 135 insert was designed for the Super, Pro and Pro TL backs. It will definitely not fit a J (don't know about your 'original' M645, but I guess it will not fit ...).

 

[MattKing]

As I mentioned in the other thread, the 135 insert is only functional in the special 135 back.
Something to do with having to rewind 135 film, I expect.

 

[darkroommike]

BTW, and apologies-this is a little off topic, but when you use up your 220 film you can convert your 220 insert to use 120 film just by removing a little wedge on one side of the insert. Google for images on the procedure.

 

[Cholentpot]

BTW, and apologies-this is a little off topic, but when you use up your 220 film you can convert your 220 insert to use 120 film just by removing a little wedge on one side of the insert. Google for images on the procedure.

Humph...interesting. I have a useless 220 insert that I've been saving for a rainy day.

 

[Huss]

BTW, and apologies-this is a little off topic, but when you use up your 220 film you can convert your 220 insert to use 120 film just by removing a little wedge on one side of the insert. Google for images on the procedure.

I have both the 120 and 220 inserts, and the pressure plates are at different positions. So while this hack will let you use it, there maybe focus issues at wide open apertures.

 

[darkroommike]

I have both the 120 and 220 inserts, and the pressure plates are at different positions. So while this hack will let you use it, there maybe focus issues at wide open apertures.

This issue has been addressed before, the film rides on the rails inside the body (or magazine) this is what determines the plane of focus, not the pressure plate.

 

[Huss]

This issue has been addressed before, the film rides on the rails inside the body (or magazine) this is what determines the plane of focus, not the pressure plate.

Then why is the positioning different? When I load the film onto the insert, I can clearly see that it rides on the pressure plate, coming into full contact with it over the entire surface.

 

[MattKing]

Then why is the positioning different? When I load the film onto the insert, I can clearly see that it rides on the pressure plate, coming into full contact with it over the entire surface.

Then when you push the insert into the camera, it presses the film against the rails, which themselves determine the plane of focus.
Other than the problem with the film counter, the biggest problem with the 220 option is that it would provide more pressure against the film + backing paper, which in turn creates more friction, which in turn increases the potential for wear for both the insert and, more importantly, the winding mechanism in the camera.
If you were to do the opposite - load 220 film in a 120 insert - the larger "gap" might create the sort of problem you are probably thinking of - too little pressure on the film, and therefore possible problems with film flatness.