Re: Mr Pinhole pinhole calculator

Murray,
I was in touch with Larry recently because I had problems with his Zone Plate
file creator. He told me that he has had a lot of difficulties with his
computer after a nasty virus attack (remember all to update your virus
definitions every week and to run your anti-virus programs...). This might
explain what his happening.
He's attempted to fix the ZP file creator, but the last time I checked (a few
days ago) it still was not fixed.
Cheers,
Guy

Murray wrote:

> Does the Larry Fratkin pinhoel calculator on MrPinhole.com work?
>
> Certain output fields do not change until inputs are changed alot...
> for example,
>
> (hard to put simply into words)
> attempting to find optimal pinhole size for a given focal length with the
> Javascript calculator...I enter a focal length and the optimal pinhole
> diameter gives me an optimal diameter. If I enter that diameter into the
> pinhole diameter input field, the calculated optimal focal length is nowhere
> even near what we started with. Changing diameter to affect the optimal
> length (I mean, it's only natural to try and figure out what the heck is
> wrong with the conflicting results), I find the following results:
>
> Input Output
> fl 38 mm opt. diam .254 mm, doesn't change until fl reaches 41
>
> pd 0.25 mm 25.4 mm, jumps to 50.8 mm with .27 mm p.d.
>
> It's like there is a table of results and a slight variation in input
> suddenly bumps the output to a new value...changing pinhole diameter from
> 0.26 to 0.27 mm shouldn't change optimal f.l. from 25.4 to 50.8 mm.
>
> This what I used to come up with 0.25 mm for 38 mm f.l on my 35 mm
> conversion ....maybe I need to go find my slide rule?
>
> Murray
>
> _______________________________________________
> Pinhole-Discussion mailing list
> Pinhole-Discussion@pinhole.com
> unsubscribe or change your account at
> http://www.pinholevisions.org/discussion/
Received on Tue Nov 6 15:06:15 2001