The XPan back
Mamiya never made.
The MamiyaPan Pro conversion kit turns a standard Mamiya 645 Pro film back into a MamiyaPan Pro panoramic back. Mount it on your 645 Pro or Super and get 30 panoramic 56 × 20.5 mm frames per roll of 120, in the same 2.7:1 frame shape as the Hasselblad XPan.
Hasselblad XPan frame: 65 × 24 mm. MamiyaPan Pro frame: 56 × 20.5 mm. Both are effectively the same 2.7:1 panoramic shape.
Sleeved roll comparison
The mechanism
The Mamiya 645 Pro back's frame spacing disc is a stamped metal disc with 9 indexing notches. Each notch triggers the stop lever once per advance, giving you 15 frames at 56 × 41.5 mm per roll. The MamiyaPan Pro replacement is a laser-cut 18-notch disc sized for half-frame spacing. This lets us double the frame count while keeping the original drive train and spring coupling.
What's in the kit
- 18-notch frame spacing disc. Laser-cut spring steel. Replaces the 9-notch OEM disc inside the 645 Pro back's frame spacing assembly.
- Gate mask. Two-material hybrid (self-adhesive vinyl base plus rigid PET masking strips) that reshapes the film gate from full 645 to the panoramic frame. The PET strips are intentionally oversized and fit-to-back: test-fit first, then trim or sand the short ends only if they bow.
- Viewfinder overlay. So the camera shows you what you're actually capturing, not the unmasked 645 frame.
- Printed instructions and fitment tools. Sandpaper for targeted disc troubleshooting and PET strip fitting; the PET strip ends can also be trimmed carefully with sharp scissors if needed.
Install notes - a word of warning
This is a DIY kit, not a drop-in accessory. The film back has to be opened up, the frame spacing assembly has to be completely disassembled to swap the OEM disc for the new one, and the gate mask has to be properly aligned and stuck down. Plan on a full evening of work (or more) - I've tried to get my tolerances down, but dealing with old camera parts like this is always a headache. Read the full install guide before you commit.
The disc itself is precision laser-cut, but laser cutting can leave burrs that show up under load. Some installs need a few seconds of targeted sanding on a single tooth or sector to land in the mechanism's friction sweet spot. The PET gate-mask strips are intentionally oversized, so they may need a few passes on the short ends to sit perfectly flat in a given back. The instructions walk through both checks before film goes in.
The conversion is fully reversible. Save the OEM disc and you can return your film back to standard 15-frame 645 anytime.
Format comparison
| Format | Size (mm) | Ratio | Area (mm²) |
|---|---|---|---|
| 35 mm standard | 36 × 24 | 1.5:1 | 864 |
| 35 mm panoramic crop | 36 × ~13 | 2.77:1 | 468 |
| MamiyaPan Pro | 56 × 20.5 | 2.7:1 | 1,148 |
| Hasselblad XPan | 65 × 24 | 2.7:1 | 1,560 |
| Full 645 | 56 × 41.5 | 1.35:1 | 2,324 |
Status
The mechanism has been validated through dry cycling, backing-paper spacing tests, and multiple real rolls with various stages of prototypes. The first public kits will ship in a limited batch while production QC and documentation are finalized. Sign up below to be notified when the first batch is ready, and to watch the launch video on No Grain No Gain when it goes live.
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Sample shots
