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Re: Light Meters
In a message dated 8/23/00 3:57:21 AM Eastern Daylight Time,
Aquatic-Plants-Owner at actwin_com writes:
<< An f-stop is a factor of 2 (100% increase).
One quarter f-stop is a factor of 1.19 (a 19% increase).... Wars have been
fought over less. A 19% increase is what you get from adding a fifth tube
to a four tube fixture (figuring in obstruction issues). If choosing one
reflector over another, 19% is a huge difference. >>
Yes, Thank you. I sort of knew that about f-stops and it's log scale. now, I
have not bought any photographic equipment in years. No need for new gadgets
and bell and whistles that really don't do much except lighten the pocket.
The meters I have, came with EV to lumen -- lux conversion charts --
(Pentax 1 degree digital spotmeter, modified by Zone VI <<this is a VERY
Special meter> and a Minolta combo incident and flash light meter. Then there
is the built In 1 degree spot capability on my F4. The problem with any
conventional light meter is that they are calibrated to accurately measure a
19 % gray card -- so they lie about 1/3 of the time. The trick is to know
what those conditions are and compensate for it. A great deal of good quality
used photo equipment is listed for sale at rec.photo.marketplace.
It was not my intent to start a war. I'm a peaceful soul at heart, and four
years in Vietnam cured me of any aggressive tendencies I might have once had.
The problem with lighting I have in my tank is -- too much. And the chart
posted by another lister from the French book graphically illustrated that.
Thus far, 220 watts of 9230K PCs seems more than enough for my 120 gallon
tank populated mainly with four different swords, and a mess of various types
of vals. (but I have a standby extra 110watt fixture leaning against a
corner in the back just in case.