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View Full Version : My first pinhole camera build



ImageMaker
01-31-2005, 10:59 PM
Simple stuff, right? I took a 126 cartridge (Tri-X, 12 exposures), cut up and taped the box and wrapper to make a small pinhole camera that nested neatly into the light trap on the cartridge. A quarter made a fine film advance, and tape held a strip of the foil inner wrapper over a pinhole poked through another layer of the same stuff for a shutter.

I got one image that recognizably had *something* on it, but it wasn't recognizable as a pine cone -- all the others were underexposed by what I now believe to have been between six and ten stops...

Well, that was 1975. Fast forward to 2005 -- in the interim, I made a few pinholes (big ones, by poking a ball point pen through a notebook cover) to view eclipses, but never tried photography with a pinhole again.

Today, the last day of January, I set up my mini-lathe (which has been in the shrink wrap since my move to North Carolina last fall), used it to drill a perfectly centered hole in an M42 body cap, and then countersunk the hole on the outside surface of the cap (to avoid vignetting). A piece of .005" brass shim stock, a sewing needle (too heavy, it was .030" shaft diameter, but it was all I could find) gripped in a pin vise, and some fine sandpaper, with a couple trips to my scanner to measure the hole, and I managed a .013" hole (slightly oval, just over .011" one way, about .014" the other) with a reasonably clean edge on the first attempt -- a little large for a 45 mm focal distance, but I can make a smaller one later and reuse this one, perfectly sized, for my upcoming 9x12 sheet film cookie tin camera(s). The hole was attached on the inside of the body cap with black masking tape from a craft store (is that the same as "gaffer tape"?), and the exposed brass blackened with a Sharpie marker.

It was then a simple matter to install the body cap in place of a lens on my antique Spotmatic and load up a roll of Tri-X (some things are still the right choice even after 30 years). With anticipation of a Diafine bath, the Tri-X was poised to accept one fouth as much light as Kodak says it needs, and with my pinhole showing as a near-perfect f/128, out I went for some hand-held pinholing.

Twenty-four frames later, it was getting dark enough I wasn't sure of my exposures, and too dark by a long stretch to see the needle in the Spottie's meter (which shuts off anyway at 1/8 second when set to EI 1600). Only one exposure had been over a second, a couple as short as 1/30 -- full sun with this size hole and film speed should give 1/60.

I could hardly wait until after supper to process the film -- into the bathroom I went with the freshly loaded tank, barely pausing to put away my changing bag. Out came the chemicals, in went the Diafine. Three minutes in Bath A (man, it's nice not to have to worry about the thermometer), and back into the bottle. Three more minutes in Bath B (don't agitate too much in this one) and back into the other bottle. A two-bath water rinse (stop bath and carbonate alkali is a non-recommended mixture), six minutes in rapid fixer with agitation every minute, and back in the bottle with the fixer, too -- and off with the lid.

Yes! There were images!! And all of them look close to correctly exposed. Frame one will be in the appropriate Call for Uploads sometime tomorrow (after the film dries and I have a chance to scan it). No weird perspectives, curved-film or ultra-wide distortions; 45 mm is longer than the lenses routinely mounted in many 35 mm cameras. But obviously recognizable images, several hand held at times down to 1/4 second (amazing how easy it is to hand hold when you only have to be steady enough that the motion blur is smaller than the pinhole fuzz). A shot of a piece of gravel on the street that makes it look like the glacial boulders I used to see around Seattle when I lived there; one of the neighbor's cat with her head blurred from snapping around at the shutter sound and another reasonably clear one with my hand stroking her head (about ten seconds before the ungrateful little wretch bit me!). At least one cloud shot that looks pretty darned good in that tiny frame, at least to my aging eyeballs...

Tomorrow, black foam board and black paint, more holes to drill and pinholes to fabricate -- when I finish scanning...

ElrodCod
02-01-2005, 09:44 AM
Isn't it fun? Cheap plastic 35mm cameras can usually be found at your local thrift store for ~$1 that just beg to be converted to pinhole. Your local hobby shop should have small drill bits that'll make a nice clean (and round ;D) hole. A #80 is .014" and a .3mm works out to about .012". They're usually about a buck each & you'll need a pin vise to hold them (~$5). Throwaway aluminun pans are good for pinholes & are thinner than .005". Thinner is better; you can probably find .001 shim stock at the hobby shop as well.

Gary

ImageMaker
02-01-2005, 12:07 PM
Cheap plastic 35mm cameras can usually be found at your local thrift store for ~$1 that just beg to be converted to pinhole.

In fact, I've got three of them, identical, that I paid $1 to $2 for, intending to fly them under kites for aerial photography. I picked that model because it would fire automatically if the release was held while the film advanced; I intended to make a wind powered continuous advance and a rotating mount and let them shoot a continuous panorama, using a whole roll in a single flight. Might still get there, but those cameras aren't hard to come by, and for this kind of conversion I don't need the automatic trigger capability. Could be interesting getting into them to bollix the shutter and install a pinhole, though...


Your local hobby shop should have small drill bits that'll make a nice clean (and round ) hole. A #80 is .014" and a .3mm works out to about .012". They're usually about a buck each & you'll need a pin vise to hold them (~$5).

Got the pin vise already -- had that for decades, got it originally for drilling small holes in balsa and birch plywood for model building, in the early 1980s. Also got an assortment of X-acto handles that can hold a tiny drill bit or needle. I wonder if there are .25 mm jeweler's bits, too? The approximately .010" hole they make would be closer to optimum for the focal lengths commonly used in 35 mm. Alternately, I can get music wire and drawn guitar strings down to about .003, and have some of the .012 guitar string material on hand, left over from building a telescope a few years ago (guitar strings make great spider wires); it's pretty floppy when you have a couple feet of it, but a quarter inch protrusion from the pin vise ought to be stiff enough to drill with -- I wonder if I can find enough magnification around to grind it into a spade or D bit?


Throwaway aluminun pans are good for pinholes & are thinner than .005". Thinner is better; you can probably find .001 shim stock at the hobby shop as well.

I used the "dimple and sand" technique with the needle, so the edge that actually forms the pinhole is quite thin; at no point did I push any of the needle completely through the hole (for strength, sewing needles have a pretty blunt taper at the point); a finer needle that I could push through would make a rounder hole, and still taper the thickness. And .005" is thick enough to be easy to handle; I'd be concerned about creasing the .001" stock the same way regular aluminum foil creases. Might look for some engraving type copper foil, though, or just get a package of the disposable pie pans and call it good. Brass is nice to work with, though, and I already had it (for shimming lathe bits to center height).

ElrodCod
02-01-2005, 12:45 PM
I haven't had any problems with creasing the .001 shim stock. Put the stock on a piece of cardboard & only use the weight of the pin vise to drill the hole. Check outhttp://www.biscofl.com/metric_drill_bits.htm for bits down to .16mm.

Gary

ImageMaker
02-01-2005, 03:22 PM
bits down to .16mm.

Whoa!

Sneeze and you lose $20 worth of bits in the carpet... :P

Okay, I bookmarked 'em -- but honestly, the needle and .005" shim brass is working fine. Check the "First Shot of the Year" upload area for results...

taco
02-01-2005, 06:59 PM
In fact, I've got three of them, identical, that I paid $1 to $2 for, intending to fly them under kites for aerial photography.
Do you know this one?
http://arch.ced.berkeley.edu/kap/ ?
taco

ImageMaker
02-01-2005, 07:23 PM
Do you know this one?
http://arch.ced.berkeley.edu/kap/ ?

I do, though I lost all my bookmarks in a hard disk failure after my computer got dropped in my recent move. Thanks!

Now -- can we take pinhole photos from a kite? ;)

taco
02-02-2005, 04:59 PM
I do, though I lost all my bookmarks in a hard disk failure after my computer got dropped in my recent move. Thanks!

Now -- can we take pinhole photos from a kite? ;)
Should be possible: The link above states:

Canon Rebel X and subsequent Rebels (33K jpg) - highly recommended
During August of 1996 I built my KAP Rig No. 2 based on a Canon Rebel X single lens reflex. One might argue that the principal advantage of an SLR - composition through the picture-taking lens - is of little value in kite aerial photography. After all the photographer is usually dozens if not hundreds of yards from the camera at the time of exposure. My interest in the SLR was for a different reason and I can sum it up in one word: W I D E. I have been yearning to take photographs with a sharp, wide-angle lens and it seems the easiest route to this is an SLR

And then a body cap could be used. (If the camera accepts long exposure times, but for you, pushing the films, that should be no problem)
taco

ImageMaker
02-02-2005, 05:51 PM
Well, my concern was that with the movement of even a stabilized KAP rig, a pinhole shot is likely to show nothing but undifferentiated blue. But, as you say, in full sun at EI 1600 I can shoot at 1/60 with an f/128 hole. I bet I can slow down the shutter in one of my plastic junkers from 1/100 to 1/60 by extending the hole in the disk (if I can get it apart and back together, always presupposing), and the short focal length in those might get me down to f/90, which would keep me okay at 1/100 or so at EI 1600. Heck, put some Delta 3200 in there and I could shoot at 1/125 in bright sun with the setup I have.

For that matter, those junkers might be sharper with a pinhole than the original lens (even a close, relatively large hole). Wonder if I can make a .010 hole with this .030 needle? ;)

That would be better than sending up an antique SLR I can't afford to replace...