文档介绍：156 Alternative Digital Photography
Figure A pinhole image made with a larger, less perfect hole as the pinhole. Figure A pinhole image made with a small, sharp pinhole.
The double exposure effect is caused by the needle jumping slightly as the foil was
turned making a tiny, almost unnoticeable second hole next to the first one.
Figure The foil with the pinhole
is taped to your SLR camera body with
the lens removed.
Digital Pinhole 157
Some characteristics of pinhole cameras include:
n The smaller the hole, the sharper and dimmer the image.
n The larger the hole, the softer and brighter the image.
n Pinhole images need a lot of light because the f-number of the “lens” is on
the order of f180 (normal lenses are more in the range of to ). This
means setting your camera on a higher ISO rating (1600 or higher if you
have it available) and/or longer exposures.
n The depth of field is huge. Objects that are far away are just as much in
focus as images close up.
n You have to be concerned about dust getting in through the small pinhole
and depositing on your image sensor.
n The image will be soft and not sharply in focus.
If you enjoyed making your own pinhole, there are a few things that you can do to
improve it. The first is to start with a body cap so that you won’t have to tape it to
your camera. Then cut or drill a small opening in the body cap, about one-quarter
inch across. Next, instead of using aluminum foil, get one of those disposable alu-
minum pie pans e with pre-made pies. The pans can be purchased on their
own at the grocery store, too. Cut a small square out of the bottom of the pan and
drill your pinhole in that. The pinhole will be more difficult to drill because the alu-
minum is thicker. It sometimes helps to wrap some tape around the top of the needle
to keep you from punching a hole in your finger as you press down. Use some
extremely fine (600 grit) emery paper to sand down the backside