Re: pinhole

Rob,

I don't know what I'm thinking sometimes. I was stuck on the idea that with normal lens and while using an infrared film you have to compensate for the different wavelengths otherwise your focus will be off. As you and Marek pointed out this is irrelevant with normal pinholes focal length but as focal length increase the difference increase may become more and more significative.

I did the opposite of you I chose a fix 1mm pinhole and I got ~500mm @ 550nm and ~395mm @ 700nm. This may seem like a large difference but is it really? Now that you got me out of my own darkness, I would answer a question like this by saying, with pinholes it is much more about the effect or the degree of fuzziness that satisfy you and much less about the optimality of the diameter of the pinhole or its focal length and the only way to really find out unfortunately, is by experimenting.

Regards
Yves

  ----- Original Message -----
  From: RHobbs3@aol.com
  To: alt-photo-process-l@usask.ca
  Sent: Tuesday, April 18, 2006 7:51 PM
  Subject: Re: pinhole

  According to my math, the difference in optimal pinhole size at 550 nm and 700 nm for a 150mm camera is about .06 mm.

  Rob
Received on Wed Apr 19 10:21:31 2006