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Thread: exposure of dark evergreen trees?

  1. #11

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    Mar 1998
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    exposure of dark evergreen trees?

    absence of reflected red, blue, cyan, magenta, & yellow light?

  2. #12

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    Mar 1999
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    exposure of dark evergreen trees?

    Hmm, interesting. I wonder if Ellis is onto something. If the trees absorb all the other wavelenghts and in effect reflect just one narrow band of green, that would lead to underexposure. I was wondering if the spectral seensitivity of the meter cell had anything to do with it but I guess not, since a reflected light meter would detect the lower light being reflected by the tree (and anyway, around the green wavelengths, most cells are sensitive). But it does make sense that with an incident meter, you would run into problems since the meter measures all the wavelengths but if the reflected light is being hugely reduced (with the trees absorbing all the other wavelengths), you would get underexposure. I'm a little puzzled by why this happens only with evergreens, though. Would the chlorophyll explanation have something to do there? Ah well, food for thought....

    DJ

  3. #13

    exposure of dark evergreen trees?

    OK, I spoke to Fuji today... the rep could think of two reasons this would happen. The first is the fact that Velvia is not sensitive to this color green... sprectral sensitvity. He claimed the way to test for this is shoot Kodak chrome... I am trying E100VS, if this exposes the film properly under the same meter reading conditions, then the problem is the film itself. He suspects ths. His other suggestion was that it is possible that evergreen trees actually absorb as much or more light than the color black, and this must be compensated for? He claimed that when black items are exposed in a scene there is rarely detail to be seen, so the lack of detail would go un noticed. There is some logic there for sure.

    The strange thing I did not mention was the fact my B&W Polaroids also suffer from the same ill effect... that is how I get the scene right, first nail the Polaroid then adjust for film speed. The Fuji rep said this makes sense because the Polaroid shares most of the same spectral responses as Velvia... that suprised me, but I guess he knows? I will report my findings when I get them..

  4. #14

    exposure of dark evergreen trees?

    Bill, I didn't read the "velvia" in the post therefore the confusion. As for Velvia, I shoot it for all my color shots and I never suffer from lack of shadow detail unless the luminance range is too great. I always spot meter so I know what that range will be and expose accordingly. If it is one stop or less I pre-expose the sheet of film to help with contrast. Have you run a film speed test on it to determine if your film speed is correct? An improper film speed will really eat up what little exposure latitude you have with Velvia. But my shots in Yosemite and the Sierra are always colorful from the dark green Ponderosa Pines to the Blue skys to the red sunsets. Beautiful film.If you shoot above 4-6 thousand feet might I recommend an 81B warming filter to help compensate for the blue in the shadows. The blue overwhelms the green wavelengths so a warming filter will bring out the greens better. Art Wolfe and other shooters use this film and you can see what a wonderful film it can be when used right. Hope this helps. James

  5. #15

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    Oct 1998
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    65

    exposure of dark evergreen trees?

    It seems odd to me that the B&W Polaroid could be used as a reference for the Velvia exposure in this specific context, because of the known cumbersome sensitivity for greens of any B&W film.

  6. #16

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    Dec 1997
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    exposure of dark evergreen trees?

    With respect to Alec's answer, I think the point he was trying to make was that light meters tend to be sensitive to infrared light but film is not (unless, of course, the film is infrared film). With a reflected light meter and negative film, this leads to an underexposed negative with a subject that reflects a lot of infrared light such as green foliage. The meter sees the light, takes it into account in giving the exposure information, but the film doesn't see the light. Hence the film tends to be underexposed because the light that the meter took into account in determining the exposure never reached the film. However, I wouldn't think this phenomenon would have any effect when using an incident light meter since with this type meter you're not measuring the light reflected by the subject but rather are measuring the light falling on the subject. Brian
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  7. #17

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    Oct 1998
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    240

    exposure of dark evergreen trees?

    Yes, Brian. That's what I had in mind. Unfortunately, I was also thinking solely of negative film which wouldn't apply here either. Well, it's a continuation of my motto: "Often wrong, but never in doubt".

    If I understand his question now [obviously that is still an issue with me], I would suspect the reason for his underexposure is a difference between the spectral response of his meter and the film. He is saying the foliage is always underexposed, right? Perhaps the film just doesn't give the expected response to that particular color.
    Alec

  8. #18

    exposure of dark evergreen trees?

    I have to agree with James. When I have used Velvia either 35 or 4x5 I have had to do two things, 1 rate the film at 32 for 35mm and 40 for 4x5. And have used warming filters to warm up the blue. Velvia seems to go too blue in the shadows and I loose information that my eyes do not. An 81 a or b, when I'm shooting early early in the morning an 81c does wonders. My other question is regarding your polaroid shots. Are you filtering for this b+w film as well? A yellow or light green filter will add definition to these green shadows. Good luck on your plight, I am amazed that a Fuji rep would recommend a Kodak product of any type.

  9. #19

    Join Date
    Mar 1999
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    107

    exposure of dark evergreen trees?

    From my experience at shooting evergreens, I've always presumed it was the trees absorbing light that resulted in underexposure. If you look at evergreens under afternoon sun, you can't see any detail on the trunks. Any portion of the tree other than the tips of the needles are black or close to it, and velvia's going to make it appear black.

    Another note of metering when the tips of the trees are in directly sunlight. I've had a similar problem recently. If you use the direct sunlight ambient reading, the rest of the tree ends up being around 1 stop under. Yet, if you take an ambient reading in the tree's shade, you'll blow out the sky. The only choice is to average. I've gotten good result very late in the afternoon, when the sun is below 30 degrees, as the light rays are close to horizontal, so they can 'penetrate' the tree to expose the trunk to expose parts of the tree that would otherwise be in the shade of needles (depends on the tree, of course).

    In the harsh lighting of the SW US, I find this to be especially true (light seems very cold) whereas in humid Asia, it's not as bad (I shoot about 95% velvia). My conclusion was that for the SW, unless the sunlight is faint or you're shooting in the woods, you'll get better results w/ E100S or Astia w/ a warming filter. I'll check some chromes that I recently took on velvia quickloads, as they contain evergreens in the foreground w/ lots of blue sky (taken in the Sierra Nevada at 9000 ft around 5:30pm).

  10. #20

    exposure of dark evergreen trees?

    That is very true of shooting Velvia, or any chrome in bright midday sunlight, be it in Asia or the Southwest US. But the reason is that the film (and especially the color papers for prints) don't have the latitude that B&W or color neg film has. You therefore have to make a choice. Do you want good shadow detail or nice bright highlights? You can have both if you print but not on the slides. If you have good blue skies the information will be on the slide but you have to learn to mask when making a print to pick up the shadows. I just recieved a book by Christopher Burkett and he has the most georgeous color prints I've ever seen. And his images taken in full sun are unbelievable with all the detail you could ask for from subtle deep shadows to brilliant highlights. He shoots 8x10 chromes, mainly Velvia and these have to be seen to be believed. And no computer manipulation at all. All hand printed. Just averaging or bracketing will not ensure good slides as you may lose too much detail at both ends. You can pre-expose the slide material then spot meter to set the correct exposure for the shadows to show density and therefore let the bright areas fall where they may or vice versa. Or you can wait until the light is softer and the subject brightness range comes within your materials bounds. Kodak E100s or Provia/Velvia or any other reversal material will act the same way. With careful positioning you can use a ND grad to help but precision counts. Have fun shooting. James

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