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 13: CAMERA SHUTTER

Finally, this thing has been giving me quite some trouble and headache. As I started building the shutter I came to apoint where I realized the mechanics for opening and closing it would be in the way of the blades, thus I had to rethink some things there. I had to make the whole unit slightly higher too allow the trigger to be out of the way. My initial idea was to try and find some kind of spring to pull the blades back as the trigger is released but I realized that a simple rubber band would do the thing just as good, or at least before it gets all dried up and break, but then i just replace it with a new one. As usual I took care to make all the parts as precise as possible where it mattered which again turned out to be hard and smaller adjustments had to be done along the way. As you can see the mechanics for opening and closing the hole is similar to that in the aperture, only here the blades can not overlap the same way since the hole must be closed entierly. This proved to be quite tricky to solve because the shapes of the blades are critical for them to not get stuck in each other as they move in and out across each other. I made several animated tests in 3D studio and some for real. The trick was to at all times have a part of the blade over or underlap the one next to it, and also the curve on the inside had to be perfectly smooth too allow the blades to run perfectly above or under the next and not get hooked up in each other, if that happens the shutter will not close entierly and the picture obviosly overexposed at one point in the middle. But with the current configuration Iīm quite certain this unit will work without problems.

Camera shutter unit.

Shutter opened and closed.

Below you can see the internal mechanics and a few in progress shots and the parts involved. The last image probably tells the most. The trigger comes in at the upper left corner (attached with some super glue) and when the buttom is compressed a metal pin pushes the disc thus opening the blades. As you can see on the final module these mechanics are covered, thatīs because I realized I had to do something to hold the disc down othervise it might pop right of the center hub aroung which the disc rotates as itīs being pulled back by the rubber band when the trigger is released. The in progress picture also shows the first set of blades I did which did not work very good but got stuck in each other all the time. With the shutter now complete I have all the mechanical components I need for the actual camera unit, the tilt and shift controls will be built with lego technic parts later on. Now I will proceed with building the front framework housing the aperture, shutter and lens. And as that is done I have the bellow left to do.

Shutter mechanics.

Shutter under construction.

Shutter under construction.

Continue to chapter 14: Ground glass

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