Re: Camera Size?

----- Original Message -----
From: "ROBERTSON,TRAVIS J" <IS-TJR@womans.com>

> Thanks for your reply. I am learning about the science of pinhole cameras
> and I must tell you my head hurts at times trying to figure it out.

Stop hurting yourself!!, we really don't need to figure out any science, that
was done by Lord Rayleigh back in the late 18 hundreds. Take any calculator (the
one provided "free" by Mr.Gates is fine) and any of the formulas widely
available in many pinhole sites (www.pinholevisions.org is a good starting
point) and you are set.

> As far
> as the result, look at this web site. http://marthacasanave.com/lenin.html
> . I really like the dreamlike quality of these photos but I would like to
> have the images a little sharper.

Shooting 16x20 is maybe not the best way to get "dreamy" images. You'd be
better off shooting smaller formats and enlarging the results. You should
experiment with different pinhole sizes until you get the desired effect.
Another way to get "dreamy" picture is by using Zoneplate lenses (pinhole
cousings), mines are not that dreamy but may give you an idea, check
http://members.rogers.com/penate/ZP120.html and
http://members.rogers.com/penate/ZP120_2.html

>What I can not figure out is how
> they did this. See how even the light is. With my oatmeal pinhole camera,
> more light is located in the center to the photo and gradually gets darker
> on the sides.

Your pinholes probably are not that clean (burrs around its edge) and maybe made
using somewhat thick material. Oatmeal cameras should have less progressive
fall off compared to flat film plane cameras. One way to prevent fall off,
other than using clean pinholes made using thin material is to make cameras with
focal length distance equal or larger than the diagonal of the format. If you
don't remember what Pythagoras Theorem is about, just take a rule and measure
the distance between the corners of your format, the focal length of your camera
should have that distance or above.

> Today, I'm going to find something that will measure the
> pinhole size. I have been cutting up a coke can and poking the hole in it.
> I then sand the back down to try and make a clean hole.

I suggest you cut the piece of the can, sand it to remove the plasticky coating
, then do a poking and at the same time drilling action, sand the back and then
gently insert the tip of the needle and rotate it several turns, this just to
clean the hole, "sand" it again only this type use a pencil eraser and then do
the rotating action with the needle again, finally, a burst of canned air at
both sides.

Guillermo
Received on Thu Aug 8 16:38:45 2002