Pinhole photographers: what am I doing wrong?

I’ve been interested in pinhole photography for a while, and I’ve gotten some decent results using a pinhole lens I made for my SLR, so this weekend my wife and I decided to try making one of those pinhole cameras out of an oatmeal box. The directions we followed are here.

This was the first time either of us had tried to develop photos on our own, so we turned the bathroom into a darkroom and got to work. After some experimentation we got some results, but for some reason only a small part of the paper is picking up an image. We’re using Ilford 5x7 photograhic paper instead of film.

Here’s what I’m talking about:

First image; this was a five-minute exposure.

Second image; this one was seven minutes.

Any ideas as to why the image is only on one small section of the paper?

(Mods, if this needs to be in GQ, please feel free to move.)

IANAPinhole Photographer, but my guess is that there’s insifficient light on the rest of the film. If that’s the case, then either a.) trying a brighter scene or b.) enlarging your pinhole (which will cause the sharpness to deteriorate but wuill significantly increase the light incident on the film) will give you an im,age on more of the film.

I wasn’t going to reply to this, since all I have are WAGs, but I figure it’s worth a bump. I don’t know much about pinhole photography, but it looks as though your “lens” is not “wide” enough to cover the format you are shooting (5x7 photo paper). I think the problem is with your hardware. I suspect you need to re-make the camera, likely with the pinhole further away from the paper (or perhaps as CalMeacham suggested, a wider hole). I checked out the website, and I just wonder it you perhaps made a mistake in following the instructions? Your photos appear to have had the paper being exposed horizontally, while the ones on the site are exposed vertically, does that offer any clues as to potential errors? Did you perhaps load the camera incorrectly? Obviously these are not very helpful answers, but hopefully a more expert opinion will be drawn in by the bump.

Thanks for the suggestions. I’m not sure about either of those, though.

CalMeacham, I don’t think it’s a matter of letting more light in; we tried an exposure as long as ten minutes, but the paper was pretty well whited out; we got no image at all that way.

And Quint, I wondered about the paper-loading as well; the directions say:

That sounds to me like it’s supposed to be loaded horizontally, right? The camera is a cylinder, standing upright, so “the 7-inch [i.e., longer side] going around inside the camera” sounds to me like it’s supposed to be horizontal. I wonder if maybe the sample photos on that site are cropped? That doesn’t seem likely to me, for some reason.

There’s one other potential problem, and now that I think about it, I bet this is it: During construction, some Krazy Glue got onto the pinhole. I wiped it away as best I could, and re-made the pinhole to be sure it was clear, but I wonder if there’s some now-hardened glue built up around the pinhole? That might account for the fact that only one little spot on the paper is getting any light; it could be acting like a “light-tunnel” or something.

I know there’s a hole there, because if you hold the camera up to the light and look in, you can clearly see that there’s a pinhole of light getting through. But I wonder if some of the glue got built up around the hole and is monkeying with the image. That sounds like it’s worth investigating.

Again, thanks for the input, both of you.

What is this “film” you are talking about? What kind of format is it, .jpg?

No, it’s a high-density position-space rasterized format, with variable-geometry pixels. The quality’s great, but the file sizes are so large they need to be kept on a specialized medium.

THe larger your hole is, the worse the focus will be. You’ll get a sharper image with a smaller hole. So enlarging the hole is not necessarily the solution. When I fiddled with cardboard cameras, long ago, I found I had to “straighten” the hole sometimes. You might also try cutting a larger hole, like quarter size, then laying a “cleaner” material than carboard over it–the lightproof black plastic some paper comes in, e.g.–and making the hole in that “cleaner” material. The thinner the material, and the cleaner the edge, the better and straighter the image.

Looking at the photos, what lissener said is the most probable problem. We always used thin sheets of metal (brass, aluminum, tin) to make our pin holes.

Wikpedia has a good explination and suggestions.

There’s an optimum pinhole size that you can find in a number of references, but small changes from that won’t completely wreck your image.
You can buy good pinholes from places like Edmund Optics. “Red” Strong suggested a good way to make them in his classic “Methods of Experimental Physics” – make a stack of thin metal shim sheets. Use a good, clean round needle – place it in the center of the stack, pointing down, and hit it with a hammer hard enough to drive it partway into the stack. You’ll be left with a set of nice round pinholes, with many of them varying in size.

The ones you gert from plasces like Edmunds aren’t made this way. Often they’re electroformed, and are very flat with very round opening.

Re. making the hole, I followed the directions linked in the OP; cut a large-ish hole in the cardbord, then made the actual pinhole in a piece I cut from a Coke can. The hole is approximately 0.3 mm across, which I figured out by taking a macro shot of it with my digital camera on its sharpest setting and enlarging it until I could count the pixels across the hole. (Insert techno-joke here.)

I still have a suspicion that there’s some built-up glue on the hole. I’m going to try removing the soda-can part and making a new hole-piece in a new panel of a Coke can.

If that doesn’t work, I’m going to buy one of these.

You did the sanding of the metal? Didn’t force the hole too early? Because the problem really does look like an asymetric or somehow fouled up pinhole.

Anyways, try again. All it takes is time.

And Coke.

All it takes is two things, time and Coke.

And emory cloth.

The three things it takes to make a pinhole camera are (please god, kill me) …

Love that answer.

For those of you with standard SLR cameras, a quick way to make a pinhole camera is to get hold of a spare body cap (the thing you put in place of a lense when carrying the camera without a lense attached) drill a 1/4 inch hole through the center of the cap. Make a pinhole in aluminium sheets as described above in other posts. cut the sheet down to 1/2 inch square and carefully tape it to the inside of the cap using duck tape or similar.
You should be able to use this modified body cap now as a pinhole lense for your SLR. It’ll take some practice to get the best results, experimenting with different pinhole sizes and exposure times. Make sure you cover up the eyepiece when taking pictures or you will risk light leakage.

I got this info from an old UK camera magazine, and got some good results with my Cannon SLR. I don’t know if it would be possible to use the same technique with a digital SLR camera.

talk about “Love that answer”! Anyone hear of a digital pinhole camera? I would love to hear of such a thing. The most amazing marriage of the oldest and newest in photographic technology. “Ah yes, for this we used my digital camera obscura. A bit bulky, but wonderful results.”

Well I was going to come in here and recommend you get in touch with my brother because I knew he had been playing around with pinhole cameras. And then I noticed that the OP was jackelope, who is the previously aforementioned brother…

I have. Some specialized scientific instruments are really nothing more than a digital pinhole camera. Pinholes have two key advantages over lenses: They have a very wide depth of focus (theoretically infinite, for a perfect (zero-size) pinhole), and they work the same for any wavelength of light (well, any significantly less than the size of the pinhole). This is especially important for the higher energies like X-rays and gamma rays: It’s very difficult or impossible to produce standard optics (lenses or mirrors) that work for those, but a pinhole always works. And after you go through the optics, you need to detect the image somehow, and the best option for that is usually a CCD (the same technology as is used in a visible-light digital camera).

Chronos do you think a normal digital SLR’s CCD would work for the long exposure times necessary with optical pin-hole photography? I know only a little about digital cameras. Also are their CCDs sensitive enough for the low light levels comig through a pinhole.

Bippy, if you’ve got a digital SLR, you could almost certainly do it. If camera can take interchangeable lenses, and has the capacity to take long exposures (up to maybe 30 seconds), you should be set.

As for making the lens, I used the instructions here to make one, but it didn’t work terribly well; I ended up drilling out a 1/4 inch hole and covering it with aluminum foil, in which I made the pinhole. Now it works great; that’s what I used to make these.

Fantastic! That’s what to expect from a pinhole camera. Very good pics, too (not just technically but also aesthetically).

I don’t know much about the practicalities of photography, but I do know that CCDs typically have very high efficiencies (generally around 90-95%). So if it’s possible to capture something on film, it should certainly be possible to capture it on a CCD. At least, on a black-and-white one… Color filters will decrease your efficiency. I don’t know if a standard digital camera in black-and-white mode would gain back that efficiency, but even in color, they should be at least comparable to film.

Chronos, many digital cameras can actually tell you their ISO rating, just like the ISO rating on film. I just got a FujiFilm FinePix Z1 last year, and while it can’t do long exposures (darn it), it does have variable ISO settings, going as fast as 800.

NoClueBoy, thanks! I’m glad you liked the photos.