Home  1: Introduction and research  2: Basic parts and materials 
3: Initial test box  4: Framework mockup  5: Designing lens and aperture mount 
6: Designing camera back and film holder  7: Design tweaks  8: Film holder construction 
9: Camera back construction  10: Camera aperture failure  11: Camera aperture success 
12: Camera back framework  13: Camera shutter  14: Ground glass 
15: Camera front framework  16: Bellow test  17: Remade bellow 


CHAPTER 9: CAMERA BACK CONSTRUCTION


Here we have the camera back/film unit almost completed, the only thing that is missing right now is the dial pointer and graphics on the back. As you probably see I have made some changes to the design, mainly around the back side of it. As I laid out the plans and tried to think everything through I was afraid that I would end up with a light leak above the film plane as the film holder was going to be inserted from above. I solved that by having the entire film holder unit being inserted from behind instead, and the way I lock the thing into the case is similar to the old design. In the third image you can see the case without the film holder inserted and the film cover partially open on the front, note that this is not the shutter but only a cover that is supposed to protect the film from being exposed when this unit is removed from the camera body. Most parts of this case consist of two or three layers of cardboard and itīs very sturdy. The two sheets lying at the side of the case are the back covers for the film holder. As the film holder have been inserted the small square sheet is placed towards the back and then the larger sheet inserted from the top and slid down over the inner cover. On the inner cover piece I will add some foam and other material that gets squeezed slightly along the sides making the back completely light proof. The holes in the sheets are openings to make the film number dial visible.

camera back front

Camera back piece, front view.

camera back back

Camera back piece, back view.

camera back case

Film holder case.


Below you see the back of the film holder that Iīve made an addition on. As I started experimenting with the film roll I discovered that it had more film rolled up on it that I previously thought, that made my calculations for the dial movement wrong and it would turn way beyond 360 degrees before the entire film had been exposed. I solved this problem by adding a small gear to the dial axle and then adding another larger gear beside it, thus down shifting the speed of it as the film gets advanced. This addition also helps making the entire thing more light proof once inserted into the case so no harm done anyway. In the end the camera back just became a bit longer than expected but thatīs fine. Now as I had all this figured out and built and I was going to assemble the whole construction I realized I had overlooked on thing. As the dial axle was sticking out and the rear lock piece/sheet comes down from above it, it was impossible to close because the axle blocked it. After some thinking I decided to just cut the axle flush to the film holder back and glue the dial pointer to it, then it would work but it means that I canīt take the mechanics apart if I need to repair or replace something without breaking the dial pointer, but for now I donīt care about that. If it happens then I just need to make a new pointer and glue that to the axle.

modified film holder

Addon to film holder.

Continue to chapter 10: Camera aperture failure


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