Pinholes

[eddie]

you can get small drills for model trains at your local model store. these help as the hole is (generally) round and you know the exact size. i can not remember the exact sizes off the top of my head. i have many pinhole cameras. it is great fun and addicting. be careful!

if you are using 4x5 try shooting a 25-35mm "FL" and then about 75mm. they are two great "fl" the 25 is ultra wide and lots of fun. lots of vignetting on the 25. you may want the 35 for that reason.

eddie

[Greg Lockrey]

Here is an example of a "macro" pinhole. It is a image of one of those Japanese shadow box carved from cork of Pagota and swans. The bellows extension was about 300mm and 1 hour exposure. The image is about 1:1 on 4x5.

[Michael Graves]

Does the thickness of the material affect the image? Could one drill a small hole in a lensboard and use that? If so, would the thicker wooden boards for a Korona or 2D work better than the thin metal ones for my Toyos?

[Greg Lockrey]

The lazer cut hole that I have is on pretty thin gauge stainless. I would think that thinner the better so that the perspective at the film edge won't "see" an oblong hole.

[al olson]

I submitted a post in an earlier thread about how I made a cardboard lensboard with an aluminum foil pinhole for my Super Graphic. The foil was punched through with a needle and the rough back of the foil was smoothed by using emery paper. Afterward, the needle was reinserted and the hole appears to be as round as the needle.

By measuring the diameter of the needle with calipers, the f-value can be computed for any of the distances of the pinhole from the film plane. This is an aid in determining exposures.

I don't see that the pinhole must be perfectly round with laser cuts, etc. I would bet that a triangular hole would work just as well. I think that the sizing of the hole is more important than the shape, except perhaps for point-sized specular highlights (now if we could punch out a star-shaped hole? ).

My photos of the lensboard and foil pinhole are contained in the prior post:
http://www.largeformatphotography.in...945#post231945

Regards,

[Jim Jones]

For determining pinhole diameters, or focal lengths for existing pinholes, try http://www.pinhole.cz/en/pinholedesigner/. A user constant of about 1.5 with this program gives the best on-axis sharpness, although many photographers prefer a slightly larger pinhole. Contrary to popular opinion the diameter of the pinhole is fairly critical. There is a small, but noticable, increase in sharpness at the optimum diameter. Wide angle pinhole cameras are a bit sharper than longer focal lengths for a given film size. Large format yields more detail in the image than small format. The material used for a pinhole should be very thin. .001 brass shim stock is good, although a bit difficult to work with. I prefer .002 brass shimstock. The dimple, sand, and and punch technique thins the material at the pinhole anyhow.

An excellent guide to pinhole photography is at http://pinhole.stanford.edu/. Another interesting article is http://www.pinhole.com/archive/371. http://home.online.no/~gjon/pinhole.htm has a range of information on pinhole photograp[hy, and some good links. The definitive book on the subject is Pinhole Photography: rediscovering a Historic Technique by Eric Renner.

[walter23]

Great stuff, thanks a lot. I'll try to get an ultrawide pinhole together soon here.

I also found a site purporting to sell sets of 12 apertures (laser drilled on 0.001" stainless steel) for $33 (pinholeedun.com).

BTW, has anyone ever tried one of those whacky "pin specks" mentioned on a couple of sites? I don't have the link handy but briefly it's the inverse of a pinhole - a suspended dark spot (e.g. on a transparency sheet or embedded in glass), which gives you a negative image (shadows of light emitters cast by the speck). The only person who seems to have done it is the guy who wrote a short paper on it for some obscure journal. Sounds like the signal:noise would be very low and light intensity almost too high for practical use in a pinhole type camera, but it's still kind of interesting.

[rippo]

i use the dimple-n-sand method that dpetersen mentioned. works great! i also use my scanner to determine the actual hole size. just scan at high res and count pixels in photoshop.

here's a pinhole shot taken on my homemade 8x10 with a paper negative. it was a test shot, and i haven't used that particular pinhole since. but i've done various pinhole shots from time to time. oh and the one below it is 4x5 film in an oatmeal container.

8x10 pinhole test:



and a 4x5 oatmeal container:

[Glenn Thoreson]

I make my own holes. It's part of the fun of using them. If you use someone's formula for optimal hole size, stick with that source. There are many sources out there and they are all a bit different. Material thickness does indeed affect sharpness. Too thick, you get diffraction that will spoil your image. .001" is too thin to work with easily and .005" is about the max. Try it, and remember that pinhole images can not be made as sharp as with even a mediocre lens. With that in mind, you'll have fun.

[katie cooke]

Michael: yes, the thickness of the material matters. Thinner the better. If you want to use a lensboard, it's best to use one with a bigger hole in there to start with, and then attach a pinhole over the hole in a thin piece of metal.

If it's not perfectly round, you can get some interesting variations in fall off, as I found out when haphazardly stabbing card or metal with a pin and using that.

here's my stuff, btw: http://slowlight.net
pretty sharp, unless there's movement.