Using a Canham 6×17 cm Roll Film Holder
on a Sinar F2/P2 5×7 inch View Camera

Objective: Explore 6×17 cm Panoramic Format

Getting into panoramic format was a leap of faith in more than one way. On the one hand, I was curious about the unusual aspect ratio, particularly when you're tempted to get the whole wide view but couldn't care less about the boring foreground or about miles of blue sky (it happens—at least in the Desert Southwest). On the other hand, I wanted do it properly, not merely by throwing away half of the real estate of an existing photograph.

First and foremost, panoramic format is just a designation for an aspect ratio that is a lot wider than tall, or even more generally, a format that is quite skinny. Effectively, you don't have to use panoramic format in landscape orientation; some horsetail waterfalls can be portrayed rather effectively in portrait orientation. Likewise, even though the name might suggest otherwise, panoramic format does not imply that you'll have to capture the whole wide view; sometimes a long lens can be a lot more effective.

Next, while 6×17 cm seems to be a popular or professional format, it does not have to be 6×17 cm to be panoramic. Any skinny piece of film or digital capture will do. For instance, some small format cameras like the Hasselblad XPan expose 24×56 mm on 135 format film. Another alternative is to use a 5×7 inch or 8×10 inch view camera and only expose half a sheet of film at a time. This can be accomplished by a split dark slide. I assume this approach requires substantial amounts of rise or fall of the camera to expose the respective half of the sheet, along with commensurate coverage of the lenses.

Last but not least, alternatives to 6×17 cm are not particularly useful if film availability and processing for these formats is limited. This applies in particular to larger formats such as 7×17 inch, however fascinating the idea may be (imagine the experience of looking at a view finder of that size, and you'll get the idea). By contrast, 6×17 cm uses standard 120 medium format film, which I hope will be available for the foreseeable future. Therefore I concluded that 6×17 cm would give me a good balance between real estate and flexibility.

The question then becomes: how to capture 6×17 cm format with perspective control and make it at least somewhat affordable? I had read about a V-Pan camera. From the only image I found on the world-wide net at the time I concluded it is some kind of view camera for 6×17 format, hence it would do perspective control. But I could not find any information about availability and pricing. I also read about the Linhof, Fuji, and (more recently) Horseman panoramic cameras, along with their capabilities and limitations. None of these cameras offers perspective control, except for the rise and fall of the Horseman.

The prices of these cameras didn't encourage casual experimentation either. For instance, a Linhof Technorama 617s III with a single wide-angle lens (Schneider Super Angulon XL 72 mm or 90 mm f/5.6, corresponding to 17±2 mm in small format, see this table) runs close to $10k (at B&H). The body alone is about $4k, which leaves about $6k for the wide-angle lens ($5k at Badger Graphic). Substantially that same lens, when used with a large format camera, can be had for just under $2k (at Badger Graphic). The panoramic version uses the same glass, but needs its own focusing mechanism, and a custom conical mount. Every lens I'd add would need its own focusing mechanism and mount, and there are only 5 different focal lengths available from Linhof, ranging from 72 mm to 250 mm and $4k to $5k.

The long-awaited Canham 6×17 cm Roll Film Holder

Enter the Canham 6×17 cm roll film holder. It looks not unlike the 6x9 cm Horseman roll film holder I had used on my first 4×5 inch camera, only a lot wider. Due to it its width, it won't fit on 4×5 inch cameras[1]; it needs a 5×7 inch camera. Obviously, it will fit Canham large format cameras, and others may be used. I called the manufacturer, left a message on the answering machine, and within half an hour or so Mr Canham himself returned the call. Wow! He told me that the roll film holder adheres to international standards and that if the ground glass frame was not removable (like the Graflok back on my 4×5 inch Sinar view camera), he may be able to adapt the camera. Just send it in.

Since Sinar 4×5 inch cameras can be converted to larger formats, I didn't plan on buying a Canham camera. Not that I could see anything objectionable in owning a Canham camera. It just seemed easier to get a conversion kit, and I won't have to deal with two different camera systems. I inquired with the local Sinar representative about a format change kit or similar but was told they no longer carry analog cameras. They suggested I try eBay.

Just to be sure the Sinar might work, I called the Sinar dealer in Switzerland, Tekno AG. Yes, all our cameras adhere to the international standards. At least so far there is still hope.

Just to be really sure I called Badger Graphic, one of the dealers carrying Canham. They didn't know if it would work with a Sinar, because they don't sell Sinars, but were happy to explain their return policy and suggested I use a ground glass protector. At this point I really wanted this to work so I started looking at eBay.

At the time, my camera was a Sinar F2, which is lighter and less expensive than the P2, but also less modular. I couldn't find a conversion kit or similar that would convert my camera to 5×7 inch format. But eventually I found a whole Sinar F2 in 5×7 inch format which cost me slightly more than my 4×5 inch new. Not an optimal start, but still way cheaper than a Linhof.

When the camera arrived in the mail, I was eager to try to remove the ground glass frame, like the Graflok back on my 4×5 inch camera. I couldn't figure it out. As I was pondering the question, with the ground glass frame lifted off as if to insert a sheet film holder or similar, the spring-loaded mechanism snapped the ground glass frame back into its rest position, and promptly cracked the ground glass smack through the middle. An even less optimal start, but for the time being I scotch-taped the ground glass.

The Canham 6×17 cm Roll Film Holder on a Sinar 5×7 inch View Camera

Once I had the roll film holder and, as suggested, a ground glass protector, I was in for a surprise: It works!!! Here is how: The ground glass frame lifts off a generous 2 inches or so, which can accommodate the thickness of the roll film holder, along with one side of the ground glass protector. Lift the ground glass lever, as if to insert a sheet film holder, and install the ground glass protector. Use the right hand to insert the roll film holder an inch or two and hold the roll film holder in place. Use the left hand to pull the left edge of the ground glass frame. This fights the spring mechanism but enables insertion of the roll film holder almost all the way in.

At some point the roll film holder appears to get stuck. This is due to a rebate machined into the top of the rear frame, on the inside, right below the insertion point for Sinar's film plane metering mechanism. Use the left hand to locate the left edge of the roll film holder, gently pull it back, and push the roll film holder all the way in. You'll know it's all the way in when the vertical ridge on the right of the holder snaps into a corresponding groove in the rear frame. I'll guess this is the adhere to the international standards part.

Following is an attempt to illustrate the insertion process.

CAUTION: Do not start fighting the spring mechanism without the roll film holder inserted an inch or two. Without the support of the partially inserted roll film holder, there is a fair chance you may trigger the same snap-back that cracked my first ground glass. At least that's what I suspect it was. Considering that it is hard to find a new ground glass these days, and when you find a decent one on eBay it can be north of $100 a piece, I'm not going to try any harder to re-enact this accident.

To remove the roll film holder, rest the palm of the right hand against the rear block, pick the bottom right corner of the roll film holder, and gently ease the aforementioned ridge out of its corresponding groove. Use the left hand to hold on to the left edge of the ground glass frame. Continue sliding out the roll film holder until it is almost removed. Carefully release the left edge of the ground glass and instead hold on to the lift levers. Pull the roll film holder all the way out and gently release the lift levers. Remove the ground glass protector.

This may sound complicated, but with the actual camera and accessories in front of you and after a little bit of practice it gets pretty easy. Think of it as inserting a very thick sheet film holder against the will of a strong spring and in the presence of fragile glass. Just don't give the springs another chance to crack the ground glass.

The Canham 6×17 cm Roll Film Holder in Practice

Now I could physically combine camera and accessories into a panoramic camera. But before trying it out in practice, I wanted to prevent the broken ground glass from further disintegration. I had already scotch-taped it, which had an interesting side-effect: The matte finish tape I had used appeared to make the ground glass brighter, as if the tape was some kind of a Fresnel lens.

Once I realized this potential, I re-taped it, but this time around I covered the entire 6×17 cm center portion of the ground glass. This highlighted the portion of the 5×7 inch format that would get captured by the medium format film. With this duct-taped contraption I both fixed the broken glass and got a viable format mask. Eventually I replaced the ground glass and made a cut-out from black cardboard I got from a local arts and crafts store. The resulting format mask stays in place between the removable Fresnel that came with a subsequent eBay purchase, and the ground glass.

Meanwhile I have learned a few more things:

The actual size of 6×17 format is 56×168 mm for an image diagonal of 177 mm. Therefore, the image circle (coverage circle) of a lens suitable for 6×17 format must be 177 mm or better. Any of my lenses 80 mm and above will exceed this minimum quite generously. For instance, for the 80 mm lens, Schneider specifies an image circle of 212 mm at f/22, which is good for a maximum rise or fall of about 37 mm[2]. To put this into perspective, this is about 2/3 of the height of the frame.

When I really wanted to get the whole wide view, I have used the Schneider Super Angulon XL 58 mm f/5.6 including the requisite center filter. Per Schneider's specifications, this shouldn't work, since the quoted image circle is only 166 mm. But it does, notably for subjects that are at or near infinity! Schneider's specifications must be very conservative.

Encouraged by these results I pushed my luck and also tried the Schneider Super Angulon XL 47 mm f/5.6 plus center filter. For this to work, you have to focus to the hyperfocal distance, else it will vignette. Neither lens will allow any amount of rise or fall, hence perspective control goes out the door, but still… this is amazing! The 58 mm and 47 mm focal lengths correspond to about 12.5 mm and 10 mm in small format—rectilinear, no fish-eye lenses.

Conclusion: A 6×17 cm View Camera

The combination of Canham roll film holder and Sinar 5x7 inch view camera essentially provides me with a 6×17 cm view camera. This includes ground glass viewing and focusing (what you see is what you get), as opposed to using a separate view finder with its parallax errors, and full perspective control (correct converging lines, select focal plane according to the Scheimpflug principle), at least to the degree that the lenses have sufficient coverage.

It may be a bit more cumbersome to use in practice than a Fuji, Horseman, or Linhof, but it is not any more involved than the 4×5 view camera I was using already. In fact, since I get 4 exposures per roll of 120 medium format film, it may have a slight advantage during a sunrise or sunset with fast changing light conditions. While you're determining the next exposure value, the motorized back can advance to the next frame all on its own. Just tweak the exposure and you're ready to trip the shutter again.

Last but not least, even factoring in that by now I have switched from the Sinar F2 to the P2 line of cameras, making the Sinar F2 5×7 inch all but obsolete, and requiring the purchase of a corresponding P2 format change kit (or a couple of them for insurance purposes), factoring in a couple of spare standard and wide-angle (bag) bellowses, along with a spare ground glass or two, and quite a few ground glass protectors, most likely I have spent less than the price of a new Linhof Technorama body, and I didn't have to buy any lens.

Technical Details

  1. Beware of Chinese roll film backs on eBay that claim to work with 4×5 inch cameras: at first the idea seems clever. These backs add sort of an extension to the back of the camera, presumably mounted in lieu of the Graflok back. This permits appropriate lenses to project a larger image circle. However, this severely restricts the range of focal lengths that can be used. At the short end the restriction is the depth of the extension. This increases the minimal focal length—probably not what you want for getting the whole wide view. At the long end the restriction is the bottleneck formed by the original 4×5 frame, which remains in place. At some point this will vignette—particularly with rise or fall. If I remember correctly, possible focal lengths are in range 120 mm through 180 mm, or maybe 110 mm to 210 mm (corresponding to 24 mm to 45 mm in small format).
  2. To determine the maximum rise or fall r, consider a film format with width w and height h illuminated by an image circle of diameter d, as illustrated below:


    Notice the right triangle, formed by the short sides

    w/2

    and

    h/2 + r,

    and the long side

    d/2.

    Thus

    (w/2)2 + (h/2 + r)2 = (d/2)2.

    Solving for r yields

    r = ((d2 − w2)½ − h)/2.