ddb@mrvax.DEC (DAVID DYER-BENNET MRO1-2/L14 DTN 231-4076) (07/20/84)
You people have heard of the EV (exposure value) scale, right? Let me tell
you a story...
One day little Davy was playing with his cameras. He decided to make a zone
system calibration series, so he got out his tripod, his grey card, and his
light meters (might as well take this opportunity to check them against each
other). Oh, and a camera, and some film. The built-in meter indicated 1/15
at F4. The Gossen Luna Pro F indicated essentially the same exposure, and
called it EV 8. The Soligor Spot Sensor 2, which reads directly in EV, said
EV 6! Quick playing with the calculator dial produced the same actual
exposure, however.
Now, I've always thought that EV, meaning exposure value, was a standardized
system. It's used by many manufacturers to indicate the max and min
sensitivities of meters, for example ("at asa 100, from EV -1 to EV 18").
Furthermore, I thought that an EV number referred to an infinite class of
equivalent f-stop and sutter speed combinations. It isn't relative to the
speed of the film.
Davy was wondering what the heck was going on, so he called his friend
Stevie and asked him to check what EV 8 meant to his Sekonic L398c studio
meter. It turned out to agree with the Luna Pro F; and both of them agreed
that film speed had nothing to do with it.
The bloody Soligor Spot Sensor II continued to disagree, however. The
meanings of its EV numbers were film-speed-sensitive. They agreed with the
other two meters only at ASA 100.
----------------------------------------------------------------------------
As far as I can tell, after looking through my book collection (which wasn't
at all helpful), and paging through the books at a local bookstore, what's
going on is that the Soligor Spot Sensor II has a scale that ISN'T EV which
it labels as EV!
Can anybody comfirm or deny this diagnosis? How common is the practice of
mis-labeling scales as EV when they aren't?
-- David Dyer-Bennet
UUCP: ...!{allegra|decvax|ihnp4|purdue|shasta|utcsrgv}!
decwrl!rhea!mrvax!ddb