Ultra-short tilt/shift bellows
During my forays into unusual types of photography, I found in two different occasions that an important piece of equipment was needed but, apparently, such an accessory is not made. The first occasion was while using tilt/shift bellows. There are a few such accessories that can be used with DSLR cameras (aside from adapters for using a view camera with a DSLR body, which to me feels like driving to buy postage stamps in a 12-axle heavy-load truck designed to carry an intercontinental ballistic missile). Both normal and tilt/shift bellows for SLR and DSLR cameras normally can extend from roughly 50-60 mm to 200 mm. Focusing at infinity with a 50 or 60 mm enlarger lens, instead, requires a minimum extension of the bellows of less than 10 mm. Focusing helicoids are an alternative to bellows, but the shortest I am aware of is expensive, and extends from 7 to 11 mm, which is hardly enough (however, it is possible to modify certain helicoids to obtain a focusing range comparable to that offered by the current bellows).
The second time I found the need for very short bellows was when I obtained a UV Rodagon 60mm lens. As my only true UV lens, I wanted to use it also at infinity, but again, I needed bellows or a focusing helicoid with just a few mm of thickness.
Not having alternatives, I set down to work in my workshop/junk shack. I don't have power tools, except a few ones commonly found in a household, and therefore my manufacturing capabilities are largely limited to sawing and filing by hand. However, I do have a rather large assortment of salvaged pieces of microscopes and photographic equipment. For the present purpose, a short focusing rack was just what I needed. I used the Nikon bayonet from an old extension ring as the rear mount, and an enlarger plate with threaded M39 attachment as the front mount. Since my main purpose was to use enlarger lenses, I could use this mount and avoid the complication of a front Nikon bayonet, which would add a few extra mm of thickness.
The last of the above pictures shows the bellows closed to minimum extension. This is enough to bring the rear of the lens close to the rear mount (and some long enlarger lenses actually protrude from the rear mount, requiring the bellows to be extended). This is more than enough, for instance, for focusing the UV Rodagon 60 mm shown in these pictures to infinity (to do so, the bellows actually need to be extended by several mm).
The prototype is certainly not elegant, but it does the job. I used a synthetic leather sheet sewn into the close equivalent of bag bellows (which are used with view cameras to allow a very short extension between standards) and two stainless steel brackets from a hardware store, attached together as the main part of the shift-tilt mechanism. Placing this bracket outside the focusing rack provides more place for the bag bellows. A slightly recessed lens mounting plate for a darkroom enlarger makes an excellent front standard, and is crucial in reducing the bellows extension. The finished bellows extend from roughly 6 to 50 mm. I may change some of the hardware pieces when I find better ones, but this prototype is fully functional. It also allows practically unlimited amounts of shift and tilt of the front standard, once the bellows are extended by 10-20 mm or more. Eliminating the tilt and shift movements would allow a simpler and smaller construction, but hardly any decrease in minimum extension.
The sideways orientation of the focusing rack when mounted on the camera is not an accident (note the position of the red dot on the Nikon bayonet in one of the above pictures) - since I needed to stay as close as possible to the lens mounting flange of the camera, with the focusing rack lowermost I did not have enough clearance to mount the bellows on the camera, and the tilt/shift mechanism cannot be made much smaller. Likewise, the construction has to use relatively thin sheet metal, and therefore it cannot support the weight of the camera. Thus, a tripod mount on the bellows is out of the question. On the other hand, these bellows are lighter than a typical lens, and their weight easily supported by the camera.
The above picture shows the bellows with a large amount of horizontal tilt and shift. In practice, this is a lot more tilt than most lenses are able to accommodate, but the bellows can provide even more.