There appears to have been at least three models. The original C2/C3 version (Model 1) and a later design that was used with the C22/C33 (Model 2 for C22/C33, rubber ‘M’ covering) and the C330/C330f (Model 2 for C330, leatherette covering). This last design came in two versions differing in the attachment to the camera body (the C33 and C330 backs have different hinging mechanisms). The C220, and C220f have fixed backs, and do not take a sheet film attachment. The C330s back is removable, but no alternatives to the standard back are known at this time.
It appears that the holders for the Model 2 variants are not compatible. The C330 version has two registration pins that match recesses in the film holders. So you can use late film holders in early Model 2 backs, but not vice versa, unless you are prepared to remove the registration pins by filing to allow the holder to seat and the back to be closed. This may reduce the precision with which a holder can be replaced for multiple exposures. Mamiya instructions for the late variant of the Model 2 mentions that new holders are backwardly compatible, but not that the older holders will not fit.
The Model 1 accepted holders that slid in from the bottom. It has the advantage that the camera will sit level on a flat surface, as the back does not project below the base of these cameras.
The later version (both camera types) used a hinged back.
Both Models require some clearance at the back of the camera when used on a tripod or copy stand. The Model 1 needs at least the length of the holder, while the Model 2 is less demanding in this respect.
Two film sheath sizes are quoted: Type J for one-quarter of 4.75” x 6.25” sheet film, Type D for 2.5” x 3.5” (6 x 9cm) sheet film. These days this usually means cutting down 9x12 cm or similar sheet film. The Type D was the normal size. Holders with factory inscribed numbers from 1-3 have been seen.
| Back | Cameras | Film holders |
| Model 1 | C, C2, C3, C22, C33 | Model 1 |
| Model 2 (C22/C33) | C, C2, C3, C22, C33 | Model 2 (both early and late (C330) types) |
| Model 2 (C330, C330f) | C330, C330f | Model 2 (late C330 type) |
The film backs are for cut sheet film, and do not accept Polaroid film. Given the location of the film plane relative to the camera back, it might be possible to manufacture a fibre-optic type back, but the cost would be more than an entire camera outfit. Because the cameras do not have mid-roll film exchange (a function of magazine backs), it would still be necessary to have two bodies.
There are two known examples of user modifications to accept a fixed Polaroid back, at the expense of infinity focus with shorter focal lengths. See the C330f Polaroid description (http://CameraQuest.com/m330pol.htm).
A project to develop a removable back for a C33 body is being pursued using a spare back. This version works with longer focal lengths if a manual focus plane adjustment is used. Details will be added as they come available.