Re: pinhole spreadsheet

[Ricardo Wildberger Lisboa <wildberger@svn.com.br>]

Ok Chris,

I'd be very happy if you could send it to me. What about reciprocity
failure? Thank you very much and congratullations for that job.

Ricardo Wildberger Lisboa


----- Original Message -----
From: Christina Z. Anderson <zphoto@montana.net>
To: Alt Photo List <alt-photo-process-l@skyway.usask.ca>
Sent: Wednesday, August 29, 2001 10:12 PM
Subject: pinhole spreadsheet


> If anyone is interested, I can email them a spreadsheet I just created.
It
> is a microsoft works file, windows 98, and with the entry of one fstop
> number of your pinhole it will work out all the calculations of shutter
> speeds for all film ISO's.  For example, my pinhole is f181; I enter that
> number, and the formula for the rest is based on  this:
>
> (shutter speed at fstop of denominator)(pinhole f stop squared)
> ____________________________ (this is a divided sign)
>                         fstop squared
>
> Thus, taking the sunny 16 into account with 100 ISO film, it would look
like
> this:
>
> (1/100)(181x181)
> ___________________
> 16 x 16
>
> BUT,  you don't have to do any of this, because the spreadsheet figures it
> out.  Now, usually I miss the very obvious, and I am sure there is an
easier
> and less mathematical way of achieving all this, but what the heck!  All
you
> have to do is plug in the ISO of your film into your handheld light meter,
> get the shutter speed of your light meter to match the ISO, and then
> whatever fstop the light meter says (f16,11, etc) you just consult the
chart
> and you'll have your time.  Methinks I didn't explain this really clearly,
> but if anyone wants me to mail it to them, reply OFF LIST.  I was just so
> excited I finally figured out how to spreadsheet the calcs that I thought
I
> would make someone else's life a bit easier!  Oh, and I did test film out
> with the times and it works great.
> Chris
>