Not as surprising as you might think.Just amazing Ansel Adams knew the luminance of the moon—250 c/ft2 !
Not as surprising as you might think.
The moon is a common element in a fair number of landscape photos, and he would have had experience working in those units when working with exposure.
I read it in his book (The Negative?)but, since he explained it in foot-candles, I didn't care to remember it.Hi guys, I heard about that moon photo that ansel adams took, and I heard the story behind it to, he didnt had his light meter and did some tyoe of equation, can you guys explain that to me???
As reddesert mentioned, the moon is just another object in direct sunlight, and I seem to recall reading somewhere that A.A. used a light meter that read in c/ft² (one for motion picture use?), so it wouldn't be surprising that he thought in and used these units rather than "sunny 11" or "EV(100) 12".Just amazing Ansel Adams knew the luminance of the moon—250 c/ft2 !
As reddesert mentioned, the moon is just another object in direct sunlight, and I seem to recall reading somewhere that A.A. used a light meter that read in c/ft² (one for motion picture use?), so it wouldn't be surprising that he thought in and used these units rather than "sunny 11" or "EV(100) 12". And then he apparently opened up two stops t9 get a brighter moon, or more likely, to get as much exposure for the landscape as possible without blowing out the moon.
Correct me if I'm wrong, but many of the Weston meters read in c/ft2.
And I think AA used Weston meters.
… and they are also 30 degree coverage.Correct me if I'm wrong, but many of the Weston meters read in c/ft2.
And I think AA used Weston meters.
Yes, but the discussion is about whether AA would have worked with candles/ft2 (and been fully familiar with a value for the moon).… and they are also 30 degree coverage.
I used this site when I considered the Weston meters: https://www.westonmeters.info/light-units
Quoting: "Although not actually mentioned on the majority of Weston exposure meters, the unit in most common use is candles per square foot, or Candles/Ftsq."
"The luminance meters (not designed specifically for photography) however, do NOT use candles per square foot. In the main they use Foot-candles. But they also use Lux x 100 and Lumens per square foot. (Oh dear! Oh dear!)"
I think that that site is saying that many (most?) of the Weston meters do work with c/sq. ft, not foot candles.But the meter is designed to work with foot-candles, so the question is why Adams would think in terms of c/sq.ft when the meter does not work that way?!
Where did you learn all of this? The thing that surprises me the most about analogic photography is that there is so much to learn. But i dont where to find all of this info XDAnsel, clearly, had studied the technical aspects of photography intensively. I also expect that the Old Ones who took up photography when films and meters were more primitive, either did it entirely by the seat of their pants, or were more familiar with luminance than we are now.
Another way of looking at the moon is the "looney f/11" rule - the full moon is in direct sunlight, but its surface is fairly dark, so to correctly expose the moon a rule of thumb is to modify sunny-16 to be f/11 at 1/ISO. Let's try applying that to Ansel's situation. He had ASA 64 film, used f/32, and a yellow filter with a filter factor of 3x. This was 1941 before ASA was redefined to eliminate the safety factor, so his film was really ASA ~ 125 in today's terms. So looney f/11 would put the moon at Zone V at f/11 at 1/125. He put the moon at Zone VII to make it lighter, so that's f/11 at 1/30 sec. He used f/32, so f/32 at 1/4 sec. And there was a filter factor of 3x, so that says f/32 for 3/4 sec. Which is surprisingly close to what Ansel used, f/32 at 1 sec.
Of course, I had to count stops on my fingers several times while doing that, and there is no way I could have gotten it right while focusing and pulling a dark slide.
weirdThat text contains perhaps some key content in the puzzle:
" The Weston exposure meter can then be used to convert between the two units: From Candles per square foot to foot-candles. Simply put, it's a matter of multiplying the candles-per-square foot reading off the meter, by a factor of x4. So a reading of 10 candles per square foot would represent 40 foot-candles.since the scale is foot-candles (clearly indicated on meter face), one can derive 250 c/sq.ft. readily from 1000 foot-candles.
But the meter is designed to work with foot-candles, so the question is why Adams would think in terms of c/sq.ft when the meter does not work that way?!
Oh and, what those things you said about zones??Ansel, clearly, had studied the technical aspects of photography intensively. I also expect that the Old Ones who took up photography when films and meters were more primitive, either did it entirely by the seat of their pants, or were more familiar with luminance than we are now.
Another way of looking at the moon is the "looney f/11" rule - the full moon is in direct sunlight, but its surface is fairly dark, so to correctly expose the moon a rule of thumb is to modify sunny-16 to be f/11 at 1/ISO. Let's try applying that to Ansel's situation. He had ASA 64 film, used f/32, and a yellow filter with a filter factor of 3x. This was 1941 before ASA was redefined to eliminate the safety factor, so his film was really ASA ~ 125 in today's terms. So looney f/11 would put the moon at Zone V at f/11 at 1/125. He put the moon at Zone VII to make it lighter, so that's f/11 at 1/30 sec. He used f/32, so f/32 at 1/4 sec. And there was a filter factor of 3x, so that says f/32 for 3/4 sec. Which is surprisingly close to what Ansel used, f/32 at 1 sec.
Of course, I had to count stops on my fingers several times while doing that, and there is no way I could have gotten it right while focusing and pulling a dark slide.
Indeed it does!Yes, but the discussion is about whether AA would have worked with candles/ft2 (and been fully familiar with a value for the moon).
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