679 – Modular Medium Format System

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The brand new “Chroma 679″  is a modular medium format system, assembled with a combination of magnetic interchangeable sections to build a camera around your own style. It is designed to use readily available lenses, in their own shutters, and off-the-shelf rollfilm backs from Kiev, Hasselblad and Mamiya.

679 with optional Full Grip, large format lens and Kiev88 film back

To build your own 679 system, you will need four basic components, plus any accessories you would like to add;

  1. Helicoid front plate
  2. Lens board
  3. Mid-body
  4. Film back
  5. Optional accessories

1.  Helicoid Front Plate

All 679 cameras use the same laser cut acrylic front plate, with integrated metal helicoid, for smooth focusing.

This is the same helicoid used on the SnapShot handheld 4×5 system, allowing for lenses/boards to be swapped between systems. There is a white vinyl band around the helicoid, used to mark off set focusing distances to allow for standard zone focusing, without the need to compose on a ground glass. This needs to be marked off by the photographer themselves, as each lens will have a different focus scale requirement.

The helicoid front plate is secured to the mid-body using 4 metal thumb screws. As well as b being both secure, and light tight, this allows the photographer to remove the plate and fit it to alternative mid-bodies for different focal length lenses.

2. Lens Board

The second component of all 679 cameras is the lens board. This is a custom turned threaded anodised aluminium board, which simply screws into the front of the helicoid for a secure mount. There are currently two styles of lens board available, a standard Copal/Compur/custom size, with holes up to 54mm diameter, and a 0.4mm brass pinhole;

lens boards

3. Mid-Body

The next component is the Mid-Body. This is the main body section, which serves multiple roles. As well as creating a spacer, to mount the lens the correct distance from the film to obtain infinity focus, and providing two integrated cold shoes, it is also the central mounting point for accessory grips, cold shoe plates, and tripod mounts. There are mounting points on both sides of the body, allowing for both left and right-handed grips to be mounted. The mid-body can be supplied in any depth, from 10mm up to 120mm. There is a simple calculation below, explaining how to work out what size mid-body you will require for each lens.

How to identify the mid-body depth you require

To work out which mid-body you need, to be able to focus your lens to infinity, you simply need to take the flange depth of your lens in millimetres and subtract 42. This is because the total depth of the lens board, helicoid, and film back, with the helicoid at its shortest position, is 42mm.

For an excellent list of lenses and their flange depths (FFD), please see the table from Frozen Photon Camera Co HERE

As an example, the Schneider Angulon 90mm F6.8 lens has an FFD of 89mm. To mount this lens correctly on your new 679, you would require a mid-body with 45mm depth;

89mm – 42mm = 47mm – However, I would always recommend rounding down by a few mm, to allow for variations in lens optics, and to give a small amount of helicoid travel before reaching infinity focus, hence the Mid-Body would be 45mm depth.

The mid-bodies are interchangeable, as is the helicoid plate, to allow you to use multiple lenses. Please get in touch with me if you need clarification of mid-body depth required.

4. Film Back

This is the final section of your new 679 modular system, and the most flexible. Currently, there are 4 different mounts available, with more in the works;

  • Kiev88
  • Mamiya Press
  • Mamiya RB Pro S
  • Hasselblad V Series – Early version only, which allow manual winding of film without a Hasselblad body.
  • Plain ground glassFor critical focusing, instead of zone focus.

The film backs are designed to place the film/ground glass at the same position (‘film plane’), meaning that you can switch between film backs/ground glass without re-focusing for truly multi-format photography.


5. Optional Accessories

As well as the four basic components to build your own 679 system, there are also several optional accessories which can be added to better personalise your camera;

Full Grip – This is available in both standard black PETG, and natural woodfill PLA, and mounts to either side of the mid-body (choose left or right-handed grip when ordering) to create a comfortable grip for hand holding your 679. The full grip integrates a tripod mount on the base, along with a lidded storage area to hold a single roll of 120 film. In front of the storage area, there is a passthrough hole for a short cable release to be held in place.

Additional Cold Shoe Plate – As standard, all mid-bodies have two cold shoes integrated into the top edge. If you require additional cold shoes, for mounting external accessories, the cold shoe plate can be clipped into place using the same mounting method as the grip. As with the grip, this can be mounted on either side of the mid-body.

Basic Tripod Mount – If you don’t want to add a full grip, the basic tripod mount uses the integrated side mounting system to provide a standard threaded mount.

There is no lens, remote cable release, film holder or tripod included with the 679 – This will need to be supplied by the photographer.