35mm

A panoramic format is one where resulting images have an aspect ratio of at least 2:1 (such as the 6cm x 12cm format) (Frich, 2012, p. 10). The 6×17 format (6cm x 17cm) is a panoramic format for 120 (medium format) film. It’s aspect ratio of 2.83 is comparable to that of Ultra Panavision 70mm (which has an aspect ratio of 2.76). Potentially because of the limited utility of the panoramic format, Hicks & Schultz (2001, p. 48) identify both 6×12 and 6×17 formats (and surely, by extension, 6×24) as “freak formats.” That said, others have suggested that only images with an aspect ratio higher than 3:1 (such as 6×24) can qualify as panoramic. While proprietary (dedicated) 6×17 cameras have been (or continue to be) manufactured by Fujifilm, Linhof, Gilde (Dr. Kurt Gilde) and Art Panoram (Hicks & Schultz, 2001, p. 48), there are extension backs in 6×12, 6×14, and 6×17 formats (with and without masks) that can be used with 4×5 (4in x 5in) and 5×7 (5in x 7in) large format cameras. The one used here is the Da Yi 6×17 120 roll film extension back for 4×5 cameras.

The goal here is to use 35mm film in a 6×17 extension back, to produce a much more extreme panoramic aspect ratio. For 35mm film, the dimensions end up being 24 (24mm being the height of a 35mm frame) by 170 (170mm being the width of the film gate). This simplifies to 12×85 (an aspect ratio of approximately 7:1). All of the restrictions that apply to 120 film, as used in a 6×17 camera or film back (e.g. lens selection), also apply here.

Aside from the roll film extension back itself, there are two other necessary elements. One is the 35mm to 120 adapter, designed by Clint O’Connor, and downloaded from Thingiverse (https://www.thingiverse.com/thing:323120). The adapter was 3D printed using Nylon PA12.

 

The other is a 120 spool, in particular a Fuji “Easy Load” 120 film spool, with the center catch.

 

The steps for preparing the roll are straightforward:

1. Cut the film leader off.
2. Use a hole punch (6mm diameter was used here) to allow the film leader to affix to the catch on the Fuji (take-up) spool. (Alternatively, the leader can be taped to a regular 120 spool.)
3. Attach the 135 to 120 roll adapters to the 135 film canister.
4. Load like you would regular 120 film.

 

 

There are a few other important notes for this process. The hole for viewing the frame numbers printed on 120 backing paper must be taped to prevent accidental opening and exposure of the back of the film. Because of how the Da Yi extension back works, the take-up spool cannot be turned backwards (that is, the film cannot be rewound back into the cassette like a typical 35mm camera). Thus, it is necessary to remove the film from the extension back inside a changing bag. You can use either the top or bottom adapter to wind the film back in. The take-up spool can be removed in daylight (and also serves to prevent the film leader from being taken completely into the cassette). If the film is being sent to a lab, it is necessary to specify “do not cut”.

Focusing, on the ground glass, is done within either the green lines (within sprocket holes) or the red lines (the width of the film).

 

The number of turns necessary to allow for sufficient (but not excessive) rebate (gap between frames) ranges from 5 to 3.5 turns. The rebate will increase as film is loaded onto the take-up spool after being exposed, so fewer turns are needed as shots are taken. A roll of 36 exposures appears to fit just fine on the take-up spool – there is no apparent scratching or other damage.

The table below summarizes my results (assuming a typical roll of 36 frames):

Shot number	Number of turns
1	5
2	4.5
3	4.5
4	4
5	4
6	4
7	3.5
8	3.5
9	3.5

Some of the results from the first tests are below. Each image was scanned on an Epson V850 Pro at 1200 DPI. The resolution of each scan is 7800 px by 1150 px (or roughly 9 megapixels).

 

 

 

 

References

Frich, A. (2012). Panoramic photography: From composition and exposure to final exhibition. Waltham, MA: Focal Press.

Hicks, R., & Schultz, F. (2001). Medium and large format photography: Moving beyond 35mm for better pictures. New York, NY: Amphoto Books.