[APML] Date: Thu, 16 Jan 2003 11:29:42 -0800

["Don Spencer" <ecdon@cox.net>]

Hi List,
            I have just decided to venture into the rhelm of prime focus
photography. Eveything I have done thus far has been piggy back. Now the
questions begin.
1) Reading Jerry Lodriguss's article on knife edge focusing, I just finished
constructing one. (seen here
http://members.cox.net/ecdon/knife-edge.html)
It was built using an old slide film housing and a double edge razor blade.
The black you see in the middle is a piece of slide film used to black out
the opening where the blade mounts to the razor. In your opinions, will this
work?
2) Is there any way to test this out in the daylight?
3) This is a quote from Jerry's article. I'm not quite sure I understand
what I'm supposed to do here.
"The type of blade used in the knife edge must be taken into account. If the
edge is beveled on both sides, as most razor blades are, the focus will
actually be 1/2 of the blades thickness from where you think it will be."

Sorry this is so long, but I plan (wheather permitting) on shooting on Jan
31st and want to get all my ducks in a row before then.
Thanks in advance,
Don Spencer





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