There are also some programs for the palm pilot and probably the pocket PC
that would automate the calcs. In fact, you could use any programmable
calculator, though an HP with Omnisolve would be easier. Enter equations,
enter knowns, press solve. Even the obsolete Omnigo 100 or 120 has this
program.
But Kodak's paper dials may be easier and faster and more obvious.
See http://www.photo.net/books/professional-photoguide for a review.
tOM
On Wednesday, September 25, 2002 at 15:27, om@xxxxxxxxxxxxxxxx
<olympus@xxxxxxxxxxxxxxx>
wrote re "RE: [OM] more macro questions" saying:
> John & Mike,
>
> Sorry if I sounded flippant about the whole light calculation issue.
>
> If you're on a budget (which many of us are), or using MF gear, it's not
> just as easy as my solution: "just buy this doo-hicky and your problems
> will be solved".
>
> I like John's suggestion to look at the Kodak photguides. I have the
> Master Photoguide and used it often for exposure calculations with my 4x5
> when I had one. It's a wealth of information to navigate the maze of
> extension factors, flash guide numbers, and reciprocity failure corrections.
>
> Skip
>
>
>
> Original Message:
> -----------------
> From: John A. Lind jlind@xxxxxxxxxxxx
> Date: Wed, 25 Sep 2002 13:22:10 -0500
> To: olympus@xxxxxxxxxxxxxxx
> Subject: RE: [OM] more macro questions
>
>
> Skip,
> While that may work if you can provide TTL/OTF exposure control, or are
> using available light and use the TTL metering, everything suddenly changes
> when using flash that isn't under TTL/OTF control. Exposure compensation
> is required when subject distance is closer than about 8X lens focal
> length. I had to become saavy about how to calculate the amount of
> compensation when I started making macros using studio strobes on stands
> and firing them with a PC cord connected to the camera. Although my Mamiya
> M645 has TTL metering which works for available light, it has no AE mode
> and cannot control any flash TTL/OTF, on or off camera.
>
> Although the strobes have an adjustable output, incident light level must
> be measured using a flash meter. The reading from the flash meter must be
> adjusted for exposure compensation depending on magnification (this is
> dependent on total lens extension from infinity and the focal length of the
> lens).
>
> One can do the math using the equations I presented, or there's perhaps
> another method I had nearly forgotten about. Kodak's Master Photoguide
> (aka Pocket Photoguide) and Kodak's Professional Photoguide both have a
> nifty wheel that can be used to find exposure compensation for macros. It
> has markings for lens extension and for magnification, depending on what is
> easiest to measure.
>
> I have also worked the problem using subject magnification by simply puting
> a small ruler into the subject material being photographed temporarily at
> critical focus distance once the image to be made is composed and
> focused. By measuring the width or the height of the subject from edge to
> edge as seen through the viewfinder the magnification can be
> estimated. The 35mm film frame is about 1 inch tall and 1.5 inches
> wide. Divide the appropriate one (width or height) by what is seen on the
> ruler and Bob's your uncle, one has a sufficiently accurate estimate of
> subject magnification for estimating exposure compensation.
>
> It's not that difficult after doing it a few times . . . and it works well,
> even with finicky transparency films (including Kodachrome).
>
> -- John
>
> At 08:48 9/25/02, you wrote:
> >Mike,
> >
> >what "real" difference does it make? The AE OM's TTL exposure will handle
> >the light falloff issues, right? If you're doing macro with a manual body,
> >you're more of a man than me. Or at least one with more patience.
> >
> >Translation: I don't know the answer and I'm too lazy to research it,
> >preferring to throw hardware at the problem instead of figuring it out.
> >
> >Skip
>
>
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tOM Trottier, ICQ:57647974 http://abacurial.com
758 Albert St, Ottawa ON Canada K1R 7V8
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"The moment one gives close attention to anything,
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awesome, indescribably magnificent world in itself --
Henry Miller, 1891-1980
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