6X10 EXPANSION BACK FOR DEARDORFF 4X5 SPECIAL - V1
I’ve been excited about this little build for a while. My intention here was essentially to turn my Deardorff 4x5 Special into a mini-banquet camera— a sort of mini 12x20.
I was able to build the back from parts that I had in my workshop and some components sourced on eBay. The camera received a fresh new set of bellows and I purchased a well used Rittreck-View adapter back which came with a 6x10 spring back attached. Now if I were really going for the simple solution here, I could have just made some modifications to get the Rittreck adapter back to attach to the back of the Deardorff. It was ugly though, heavier than I liked, and more than doubled the width of the camera at it’s most compact, making it essentially a cube. Being collapsible for easy transport is important to me so I decided that I would cannibalize the Rittreck for parts and design my own collapsible back.
The build was fairly simple as builds go. I measured out the difference between the side lengths of the rear frame of the Deardorff and the film gate of the 6x10 spring back. That gave me the necessary angles and width for the trapezoidal flaps/walls that connect the two and maintain the angles of the camera bellows all the way back to the ground glass. The distance from the opening of the rear standard to the rear of the spring back turned out to be the same as it would have been with the Rittreck adapter and spring back so my assumption is that’s the minimum distance required for expansion from 4x5 to 6x10 to ensure no vignetting (approx 100mm). The sidewalls of the expansion back were then patterned out of paper to verify my math and then cut out of a dense black card stock (+insert gauge+). The card walls were eventually coated in fiberglass resin coat (polyester resin) and then covered in a black leatherette.
Two trapezoidal flaps attach to the left and right sides of the frame that attaches to the rear of the camera and two flaps attach to the top and bottom of the film gate on the spring back. They hinge via fabric hinges made from layered gaffers tape which was further reinforced with staples and then coated in fiberglass resin coat. When the two sets of flaps are joined, they form the structure of the expansion back. The rear frame and spring back assembly, with flaps in place, are held together by their own internal friction (careful measurements meant that fit together like hand in glove) as well as two sets of elastic bands stretching between eyelets at the joining sides of the rear frame and spring back (see images for clarify). The bands ensure that the rear frame and spring back won’t become displaced if the flaps get knocked or just loosen over time. When collapsed, the same bands help to hold everything together in a nice compact package, although it’s a little loose and floppy in the collapsed configuration so I’ll has a clip or additional band to resolve that.
The back in now in place and works well. All that remains in adding a few internal light baffles that fall into place when the back is in the expanded configuration. These will ensure no light leaks at the edges of the flaps where they butt up against each other.
