Click pen as a shutter mechanism

[Aaalbores]

Some days ago i posted a thread asking for ideas for shutter mechanisms for a Diana plastic camera converted into a super wide angle pinhole camera. It's a small camera, and it's going to have a filter ring on the front, so the piece of tape shutter, the sliding shutter, or any other traditional method wasn't going to work for me. One of the ideas you shared in the thread was a 3d printed mechanism operated by a cable release. I liked it a lot, but i don't have a 3d printer, and didn't want to spend money in a cable release.

The thing that fascinates me the most about pinhole photography is how simple it is (leaving aside the film chemistry, of course...) Every aspect of a pinhole camera i can do with my own hands, and i really love that. So, looking for everyday objects that could help me to build a shutter mechanism, I found a click pen, and realized it functions very similarly to a cable release, so i thought that it would be the best idea in the world to use it to operate a shutter mechanism.

I got to work and made this:

You can see it in operation in this short video:

1.31 MB file on MEGA

mega.nz

As you can see it's not finished yet. The reason is that i still don't have a proper pinhole. I need a 0,18mm pinhole, and i tried to do it myself, but the pinholes i create are always bigger than 0,25mm, so i ordered one and i'm waiting for it to arrive to finish the job.
The worst thing about this click pen mechanism is that it forced me to drill big holes in the camera to fit the pen. Didn't like doing that, but there was no way around it. Now i have to be very careful to prevent any light leak.

Now... the shortcomings of using a click pen... because it's just a cheap pen...
- It doesn't have as much travel as a cable release. Only 5mm, so the pivot point has to be very close to the pen to amplify the small movement (but not too much, or else it will get stuck)
- The click pen is really weak, and when attaching that wire hook to the ink cartridge, it has a lot of play, so i may need to constrain the motion with something that acts as a guide.
- The pen mechanism is really sensitive, pressing it softly will open the shutter, so the piece covering the pinhole must have some friction, but not so much, as the pen is weak.
- This mechanism will only be really useful when taking exposures. The rest of the time, when handling or transporting the camera, i need to rely on a lens cap or something to ensure that no light enters the camera. Or maybe adding a safe mechanism to block the button
- As the mechanism is inside, there'll be no way of knowing for sure if it's working as it should... Only when pressing the button you'll have some hint...

But, despite all these hurdles, it really works. It needs to be adjusted, it needs some black paint, but it works surprisingly good

 

[grahamp]

I suspect your shutter will just need to be a small paper panel with a hole in it moving over another fixed sheet. A black cloth cover inside may be enough to cope with light leaks. The wire could come through a slit in the cloth.

Any risk of losing track of the shutter being open or closed?

I think this is really clever.

 

[Aaalbores]

I suspect your shutter will just need to be a small paper panel with a hole in it moving over another fixed sheet. A black cloth cover inside may be enough to cope with light leaks. The wire could come through a slit in the cloth.

Any risk of losing track of the shutter being open or closed?

I think this is really clever.

i have some felt, eva foam and felt pad, so i have a variety of materials to test. As soon as i attach the pinhole i will do that
The button in this particular click pen sits lower when you click it down. In a fraction of a second you know if it's open or closed just by looking or touching it. I chose it for that reason.
Another consideration was the stiffnes of the pen's spring. If it's too hard, you could move the camera as you press the button. But the button's resistance can be changed by adjusting the length of the ink cartridge (a stick with a wire hook, in this case). I still need to cut some pieces of stick at slightly different lengths to check which one works the best.
The mechanism of a click pen is so cheap and simple that we don't give it a second thought. It just works. When you disect it, you come to appreciate the elegant simplicity and the ingenuity behind it.

Thanks!!