Shutters for pinhole cameras?

[maisiemouse]

I've recently started building pinhole cameras. The first was a 5x4 'foamcore' camera - see www.stanford.edu/~cpatton/foamcore.html for more details. I was impressed with the ease and speed of building the camera (approx 2 hours from start to finish, but I found various problems:

1) It's a bit 'floppy'. Even with loads of internal bracing, the darkslide is the only thing that keeps it square.

2) The standard shutter mechanism (a foam plug) is about as much use as an ashtray on a motorbike. If the plug is a secure fit it nearly pulls the camera off the tripod. If it's a loose fit it leaks light. I tried using the darkslide as a shutter, but found it too difficult to get the slide back in straight without moving the camera about.

3) The elastic bands used to secure the darkslide eventually distort the shape of the camera.

So, I used the same plans and built one from 6mm MDF. Looks much more professional, feels more sturdy and it's crowning glory is a real shutter, liberated from a Halina 35X (hope no-one from the rangefinder forum is reading this ). The shutter is bonded to the front of the camera, about 15mm in front of the actual pinhole. I knew that vignetting would be an issue, but thought it might look ok. The result? A circular image, about 60mm across (thereby wasting most of the film). Doh!

So where do I go from here? What are the accepted best methods for pinhole shutter mechanisms? In my mind I'm designing a spring-loaded slide activated by a cable release, but I suspect I'm over-complicating things.

Any advice will be gratefully received.

Sean

 

[PhotoPete]

I use a piece of gaffers' tape
You could also put your thumb on the pinhole while you replace the darkslide
Neither one is elegant, but both are stupid simple...

 

[glennfromwy]

It sounds like your shutter is much too far away from the pinhole. I use old shutters on mine. What I do is to mount the shutter onto the camera and put the pinhole onto slightly closed down aperture blades. Works quite well. You want to keep the opening into which the pinhole fits at least 1/4 inch away from the hole and no more than 1/4 inch in front of, or behind the hole. It will vary some depending on focal length but should keep vignetting to a minimum or less. I've had good luck with it.

 

[John Bartley]

There are thousands of old 120 box cameras languishing at flea markets. Strip a shutter off one of those and bolt it to the front of your pinhole box?

 

[rwyoung]

I have made pinhole shutters from black mat-board and black foam core. Cut two squares, say 2" on a side. In one of the squares cut a square hole, say 3/4" to 7/8" on a side. This is the front piece.

In the second piece cut a slot 1/8" wider than your square. When this one is cut it will look like the letter "U". Save the piece you cut and trim it just a little bit so it just slides easily back into the slot.

Put the U shaped piece in the back, the square "window" hole in the front and slide the little piece back in. You have a shutter. A small piece of tape or string on the slide helps so you can easily grab it.

I'd suggest making it from black mat-board. Check that it is light proof. If you get some vinetting, just make a new one with a bigger set of cut-out pieces.

On a foam-core 8x10 I made it from extra foam-core and it works great. Used it on a much smaller and shallow (wide angle) box that uses 5x7 paper. Also works great.

 

[tchamber]

Put the pinhole on the *front* of the shutter. I use an old Speed-i-o-matic. I mounted my pinholes and zone plates on 'P' adapter rings for Cokin filters, and screw them into the shutter (I had to use a stepup ring in my case, YMMV). Just be sure to make liberal use of gaffer tape so there are no light leaks.

 

[Donald Qualls]

I've got two setups where I mounted the pinhole *in* the shutter -- I unscrewed the glass from existing medium- or large-format shutters, mounted the pinhole on black posterboard, and inserted it against the tapered area just in front of the shutter leaves. With the shutter's aperture set wide open, this allows for very wide angle with no vignetting at all (my cameras aren't very wide, but I've seen this done successfully with 43 mm on 6x9 cm film).

 

[seattleboyseb]

One thing that I've been thinking about with a pinhole camera, that I'm in the designing phase on, is using cloth shutters much like a Leica. I'm still working out the logistics of it, but I think it should be feasible and relatively easy to make as long as you don't need it to move fast