Pinholing

Very old cameras used small holes instead of lenses to focus light onto photographic film. For much standard photographic work, pinhole techniques are inappropriate: for starters, they tend to require very long exposure times, and they often introduce certain distortions. But this is a hobby, not a job, so things like exposure time are negotiable; and distortion isn’t a bad thing per se.

So I’m playing with pinhole photography. Specifically, I’ve converted some old Argus C-4 35mm rangefinders ($10 a pop on eBay) into pinhole cameras. Actually, `converted’ makes it sound much more complicated than it is: there’s only one screw, a very accessible screw, holding the lens on; unscrew it and the lens comes off easily. There’s plenty of other sites with instructions for making the pinhole `lens’ – the short version is that you stick the tip of the thinnest sewing needle you can find through a thin piece of brass shim, and fix it where the lens used to be so that no light gets through except by the hole (black felt and electrical tape are friends).

I haven’t been doing this too long, and am still working on getting the cameras right. So all of the rolls so far have been test rolls, oriented more towards questions like `is it light-tight?’ than any sort of attempt at great (ok, ok, competent) composition. More to the point, the goal of the rolls I’ve taken so far was to answer (up to) three questions:

  1. Is the camera light-tight enough to actually produce any image? Seemed likely, but you never know.

  2. Is the pinhole round and small enough? If it’s light-tight, there will be an image of some sort. If the image is partially obscured or is too blurry, then the pinhole may not be fine enough.

  3. What’s the effective f-stop? If the hole is good enough, the last thing to figure out is the measure of the aperture, which is then used to figure out exposure times. But the aperture depends on the size of the hole, and I don’t have that small of a ruler. The easiest way to figure out the f-stop is to work backwards from a good exposure, based on the metered exposure value of the subject and the reciprocity-failure rating of the film. So that means these test rolls are really boring, a dozen or so pictures of the same thing, each one a half-stop more exposed than the last.

The first one

For the first try I not only unscrewed the lens, but also ripped out the shutter leaves, and (since after all there was no more shutter to open!) took off the shutter speed dial to see what was underneath it. I used a piece of black felt so cover the pinhole, taking it off for a little while to expose an image.

Onto the three questions: Answer (1) is a definite yes. Answer (2) is probably no. It probably needs to be smaller, and maybe I’m not rounding out the edges enough. Fuzziness aside, I like some of the images from this test.

For the next conversions I think I’ll keep the shutter leaves. It seemed like a good idea at the time, and was kind of fun in a destructive way, but the removing the felt lens covering thing is a pain. Live and learn. Besides, cable releases are cheap.

The second one

I tried to make a smaller hole for this one.

It was smaller. It was small enough that I underestimated exposure times on the first roll so completely that even with a dozen images over about a six-stop range, the best of the lot were still grossly underexposed. Live and learn. Nothing to scan in from the first roll; the darkroom guy at the place I brought the film saved me the cost of a proofsheet that would have next-to-nothing on it.

Took a second roll over Labor Day weekend in JHB’s backyard, and at the office; waiting for the contact sheet to come back.

The third one

For the third conversion I tried putting the pinhole much closer to the shutter – right up in front of it – to get a wider angle of view.

For the first roll, also tried color negative film instead of black and white. Also tried taking some pictures towards the sun, mostly blocking the sun itself with leaves or flowers and such and hoping for interesting diffraction and shadows. This one was kind of a wash, trying too many things all at once. Probably, again, the hole is not small enough. And I forgot to tell the lab (used a different one than usual for some odd reason) to print at least a contact sheet or index print – the fuzziness scared them off of printing any but two prints. Hmph.

Made a new pinhole, took a second roll with this one over Labor Day, also in JHB’s backyard, and at the office. The ones in the backyard have a bright arc on each frame – maybe some reflection from the overhead sun? But they’re pretty sharp, and I’m happy enough with them to bother to do the arithmetic to get the f-stop!

From the office pictures. The right exposures seem to be around the two at 512 and 1024 seconds. Correcting for the long exposure times (it’s TMX 100) Light falling onto the plants: 11.75EV.

So then

So there’s this excited page of detail, and it ends as if it’s to be extended, and then it sits unchanged for months.

What happened was this: my mom got sick, I didn’t take too many pictures, and I didn’t feel up to scanning in what I did take. There was nothing special.

Decided to wait until getting a darkroom set up before doing any more pinholing. I can’t justify the cost of processing and printing a contact sheet and then prints with such a low hit rate. And at long last, the darkroom was almost ready, and I thought there might actually be new stuff on this page soon.

So then just as I was getting comfortable in the darkroom, Katrina came along. I spent alot of time on a different hobby after the storm, and didn’t spend too much time in the darkroom. Then I moved, and all that gear is in boxes. But there’s a space in the basement here that I’ll eventually convert into a new darkroom, so this page may come alive again yet…

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