Another one of those Internet myths. When first I heard that one I wrote
Sekonic and asked. They understandably did not bother to answer, so I
went out with my gray card and my Sekonic L-308B and checked it out.
Interestingly enough an incident reading, and a properly done Kodak gray
card reading, gave exactly the same exposure.
However if I did the gray card reading as I have seen suggested on those
same Internet sites, with the card angled between the meter and the
light, instead of perpendicular to the meter, guess what? Yep I got
something like a 12.5-13% gray reading. If you use your meter and gray
card incorrectly you get an incorrect reading. Then because you are
another one of those experts you tell everyone they are fools and that
their meters are not calibrated to 18%. BTW if you do not have an
incident light meter to compare to how can you tell what your reflected
light meter (dedicated or built into your camera) is calibrated to? The
difference between 12.5% and 18% is less than 1/2 stop, you probably
would not notice the difference except in the most critical situations.
Also meters are actually calibrated with a calibrated light source, not
by measuring a reflectance, gray or otherwise.
Now lets take that 18% = Zone V thing that AA lobbied so hard for . If
we put Zone X at 100%, it can not be any higher than that by definition
(of course you can chose to burn it completely out if you want). Then
Zone V is 3.12% reflectance. Your 12.5% would be Zone VII. And 18%
somewhere between Zone VII and VIII. That kind of blows that theory out
of the water. Zone V is what ever you want to show up as middle gray on
your b&W print, and that is all it is.
Just so folks don't treat me as another Internet expert, I suggest they
go out and do some experiments. What I, or anyone else, say can be
mistaken, you should only trust your own methodical experimentation. How
else can you find out just exactly what your equipment does in any given
situation.
http://www.graywolfphoto.com
"Idiot Proof" <==> "Expert Proof"
-----------------------------------
Adam Maas wrote:
There is a photographic myth with 18% grey. The myth is the idea that
your camera's meter assumes 18% grey, which is incorrect. Meters
assume roughly 12.5% grey (there is an ISO standard). Grey cards are
18% for the reason graywolf explains, as well as due to intense
lobbying of Kodak by Ansel Adams (Who wanted 18% grey because it is
50% luminance and right in Zone V). But overall, most scenes do indeed
average out to 18% grey.
-Adam
graywolf wrote:
18% gray is not a myth. It is just that most people do not understand
where it comes from. If you go out and measure thousands of scenes
with an averaging meter, the average of those exposures will come out
to 18% gray. So 18% reflectance is an average value, where you want
to put that average value in your particular photo is up to you. It
certainly is not cast in concrete (which is usually near 18% gray, by
the way <grin>).
graywolf
http://www.graywolfphoto.com
"Idiot Proof" <==> "Expert Proof"
-----------------------------------
Bob Shell wrote:
On Dec 3, 2005, at 9:26 PM, Rob Studdert wrote:
I think blanket statements regarding optimum print resolution are
pretty
useless as the printer in concert with the driver its settings and
the paper
type determine the optimum print resolution. Also I never
experienced problems
printing images with resolutions that weren't multiples of the
natural printer
resolution on any inkjet print systems.
I agree. The idea that you have to use multiples of the printer's
stated resolution (itself a mythological beast) is another
photographic myth, like 18% gray.
Bob
