Topic: Simple Pinholery

[Sandeha Lynch]

There are all sorts of pinholes out there, laser-cut, acid-etched, etc, but probably the vast majority are home-made punched through foil.  This is my way, garnered many years ago from the ideas of other folks on another forum. 

The size of hole you need will depend on the focal length of the camera.  There are tables online that give an optimal pinhole measurement for each f/l, but it doesn't need to be too exact.  The distance between the pinhole and the film plane in the camera below is about 38mm, so a pinhole anywhere between 0.25mm and 0.35mm will be fine.

I use stiff copper sheet cut into a circle to fit in the shutter.  The centre must be carefully marked.  Create a dimple on one side with a ball-point pen by pressing down lightly against a piece of soft wood. Then, using what I think is an Arkansas oil stone (it's pretty fine) abrade the bump gently until a 1mm circular abrasion appears. This makes the metal sheet thinner for the needle. I use a numbered needle - mostly a #13 which is 0.3mm dia.

Carefully rotate the needle point against the inside of the depression - this is where you'll make burrs if you push in too roughly. The drilling motion is a bit like trying to light a fire, only real slow. Once the tip is through you should only go a short way up the 'cone' end of the needle, don't go right through - the hole is probably already bigger than the needle diameter, so stop. Carefully abrade the bump side again - and then put it on the scanner.

Check the diameter in mm under Image Size.



If it's not a circle you can try again gently with the needle. If the hole's too big - throw it away and do another.

Use a black felt tip pen in the area immediately around the hole and black paint over the back of the rest of it.  Fit the pinhole disk into the shutter, with a few spots of superglue if necessary.  This can be either behind or in front of the aperture leaves - you can check by eye whichever is best to avoid a vignette.  With the shutter open, look though the open back from each corner, pointing toward a bright light.   The pinhole brightness may fade at the corners but ideally it should still be visible.

[Nigel]

Sandeha - thanks for this. I've made some in a similar way, I've always used aluminium drinks can. Is there an advantage of using the copper? Do you know the thickness of the sheet you use?

[Sandeha Lynch]

I can't measure the thickness, but it's thin enough to cut with scissors without damaging the scissors!  Even though it's very thin it's quite protected once it's installed.  I bought it in a craft shop so it probably has some other application like enamelling glass or similar. 

Copper is a soft metal, softer than aluminium or brass, and I suspect that since less pressure is needed there's less chance of creating burrs around the edge of the hole.  Burrs will soften an image, much more than a hole that is too large.

Glad if it helps.

[astrobeck]

Great, and thanks for sharing!
I use this same method for drilling and it works very well.

 

[charles binns]

You can also use brass shim which you can buy in model shops -it's cheap and very thin. 

[f6point3]

I made a pinhole camera out of an old Yashica rangefinder a few years ago, and made the pinhole from a piece of stiff cardboard.  It seemed to work pretty well, although the focus was pretty soft due to paper fibers that I couldn't see.  I had the idea to heat up a needle point until it was red and do a quick-and-shallow insertion into the hole to burn off the stray fibers. 

Unfortunately, I haven't used it since that first roll.  I do believe there's still a roll of Tri-X or Plus-X in there.

[reuben]

You can always soften the copper sheet by simply heating it (I use a gas stove)until its red hot (use pliers or simerlar to hold it) and then just drop it into some water - much easier to work.

If you want to get rid of the burnt appearance and remove the scale that can form - pop it in some vinegar (white works best)and boil it up for a few minutes or just rub it with a cleaner. Plenty of other ways - but this I thought was the most universal.

 

[Paul H]

I've found the little metal sliding "doors" off of old 3.5" floppy disks (remember those?) works really well.

Similar method - using a needle pressing against the metal on a wooden board, but I just ground the dimple gently on a sharpening stone until it has made a small hole.  Seems to give a very clean, burr free hole.

[SLVR]

I figure that i may as well post up some "pinhole porn". I got this camera a long time ago from a toy store. It came with a book and stuff for kids, which i promptly threw out. I just wanted the camera! The kit came with all the pieces, all wind knobs, shutter, and pieces of tin foil and double sided pieces of round tape to tape on the "lens". The shutter is just a manual lever. Its quite simple.

I havent put a roll through it though! im working on that right now. I literally just loaded it now and am going to go out tomorrow to shoot the whole roll (i have bulk packs of 12 exposure superia, perfect for testing or an evening of shooting)

Anyways heres pics of the camera itself...

[jojonas~]

tintin: nifty! I'd glue a nut over the shutter lever to be able to use a cable release.

been looking for one to glue to my holga but I haven't been able to find the right one yet. what size fits?