From: Clay Harmon (wcharmon@wt.net)
Date: 11/22/02-02:37:33 PM Z
There is now a new version that directly imports all of your plotter data
and uses the actual curves to calculate everything, including a whole
boatload of new reciprocity corrections from his recent research. The upside
is that it is customized completely to your own data. The downside is that
it requires that you have access to a Windoze PC in order to run plotter.
I'm beginning to feel that this might be akin to measuring bricks with
micrometers. I do think that Sandy is quite right that for complicated
exposure situations with filter corrections in conjunction with bellows
factors, the program will keep you from making bonehead errors. It is also
useful for those really high contrast situations where the effective film
speed may only be 1/4 of the manufacturer's ISO. Rating Tri-X at ISO 25 is
not exactly intuitive, but is necessary for a SBR 14 scene. For your typical
Kitten-in-a-teacup photo, it may be a little overkill. On second thought, if
you're that close to your kitten, there will be some bellows correction.
It is nice having it on the palm pilot with all your phone numbers,
calendars (Oops, I'm out here shooting on our anniversary!), and other
digital effluvia readily available.
Clay
----- Original Message -----
From: "Jim Strain" <jstrain@iquest.net>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Friday, November 22, 2002 2:08 PM
Subject: Re: BTZS ExpoDev software for reciprocity corrections
> Sandy's explanation is quite right for the version mounted on a Palm
Pilot.
> With the version I have (mounted on a simple calculator), you input your
own
> EI, your high and low EV measurements (either incident or reflective), if
> reflective, the Zone you wish to assign, your preferred ES (achieved from
> testing), the f-Stop and whether you are doing a close up. The critical
> output then is the subject brightness range (the "SBR") which I compare to
> the curves I generated from film testing to determine development times.
It
> will also give you the depth of field and, of course, the shutter speed.
> Phil had predetermined and programmed reciprocity for TMX and TMY. Since
I
> use TMY, I have been able to rely on his curves for reciprocity. I have
> used it for all of my b&w negs for many years and it is always right on
> (within whatever reasonable range of error there is in shutter speeds and
> developer activity). The program really works and I am sure it is even
> better in the Palm version. Hope this helps. Jim
> ----- Original Message -----
> From: "Shannon Stoney" <sstoney@pdq.net>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Friday, November 22, 2002 10:05 AM
> Subject: Re: BTZS ExpoDev software for reciprocity corrections
>
>
> > Sandy wrote:
> >
> >
> > >Just a short while ago we had some discussion about reciprocity
> > >correction charts for various films.
> > >
> > >I would like to suggest that some of you may be interested in using
> > >the BTZS ExpoDev software for exposure calculations in the field,
> > >especially when dealing with complicated situations that involved
> > >filter factor corrections, reciprocity corrections, and/or
> > >corrections for bellows extension. I have been using the ExpoDev
> > >software now for about 6 months, and during the last month or so
> > >have made heavy use of it in work that often involved significant
> > >reciprocity and filter factor corrections, and sometimes bellows
> > >extension corrections. I am very pleased with the results, with
> > >excellent exposures on nearly every shot. In fact, I very much doubt
> > >that I could have done as well in making these complicated
> > >calculations manually as did the program automatically upon entry of
> > >just a few pieces of information.
> >
> >
> > Can you plug your own ISO and development times, based on your own
> > curves, into the program?
> >
> > --shannon
> >
> >
>
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