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thomaskeefer
Mar 14, 2003, 2:10 PM
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Hey
I tried my hand at using slide films on a trip to the tetons a few summers back and had some good results but on the whole it seemed that I was always underexposed.. then again on mt whitney.. is this common? I rarely come across this with prints... my setup is a nikon n90s with a 28 1.8 prime (usually) and I normally shoot aperature priority with the occasional full auto..
Any ideas?? Filters poss?? I want to move over again for a road trip this summer but I am gun shy now :(
What is the best way to get the sun to still look white and everything else looking accurate??
Thanks!!
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solo
Mar 14, 2003, 2:35 PM
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It seems most automatic exposure meters are "fooled" by too much light reflected from large bright areas of snow, ice or water. The result is that the picure gets underexposed and the white snow looks grey.
I can not explain exactly how it works, but the phenomenon has something to do with "standard" grey color which is used to calibrate the exposure meters. I believe the exposure meters approximate the brightnes of the picture and set the exposure to match it with this "standard grey".
Hope this helps.
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tim
Mar 14, 2003, 2:38 PM
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You need to comp the exposure +1 1/2 to +2 stops for full snow.
Normally a good matrix meter will figure this out for you (nothing can be brighter than the sun, therefore if the meter sees something white at EV17 or EV20, it should normalize the scene to +1 or +2 or +3... had an interesting discussion with a pro that I sold a lens to in Patagonia, he had to pack two huge flashes onto his F5 for fill, when shooting boat-ride clients in front of the Perito Moreno Glacier ... there were 5 STOPS of difference between the front-lit glacier and back-lit people.... !!!). But if not, just use e-comp and do it yourself.
My old $99 Olympus XA (manual focus, manual aperture, manual everything except exposure) had a little kick-switch on the bottom for setting "+2 comp" for shooting on snow, glaciers, etc. That was a brilliant feature for a climber's camera.
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tcollins
Mar 14, 2003, 2:42 PM
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Solo basically hit the nail on the head there. The meter does average out to a standard gray, so you need to calculate that in when shooting snow. Try to overexpose it a stop or two. Do the opposite when shooting a mostly black area as the meter will read the black as gray as well and screw up the automatic settings. It's early so I hope I wrote that correctly, it's one of those things I always have to stop and think about when shooting in winter.
TD
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cyberclimber
Mar 14, 2003, 3:09 PM
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It sounds like you have gotten some good replies on how your meter can be fooled. One thing you might try that hasn't been mentioned is using your N90s spot meter. Grass and some rocks in sun reflect at about 18% grey, with a little practice you can identify objects in your shot that you can spot meter off of to keep other bright or very dark areas from fooling your matrix metering.
One thing no one mentioned is that slide film can only show detail in 5 to 6 stops of contrast, compared with about 8 stops for print film and 15 stops for our eyes. So in an area with, say ten stops difference, from the darkest shadow to the brightest white, our eye can see detail in both the shadow and light areas, print film can show almost all the detail to be seen, but slide film will only record about half of the information you see with your eyes. When shooting slides it is always a good practice to bracket a bit since your margin for error is so much less than with print film. If your subject has a large contrast range, you have to decide what is most important to you, detail in the shadows or detail in the highlights, because you simply cannot hold both with the narrow contrast range that slide film will record.
Hope this helps.
J.C.
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tim
Mar 14, 2003, 3:20 PM
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re: holding contrast:
Well, that's why I made the point about using fill flash.
re: fooling the meter:
The 18% grey comment is very true for spot and center-weighted meters, less so for an evaluative matrix meter. The whole point of a matrix meter is that it normally can automate out the process or "zone-ing" the scene and just let you take pictures.
ken rockwell's bit on matrix meters
The above article is Nikon-centric, but the way an evaluative metering system works is pretty much standard across the board. Canon partisans will probably squirm at the wording of the essay, but, tough shit. The poster asked about his N90.
Personally I'm wondering if dude didn't accidentally kick his meter into spot or CW. I've shot plenty of scenes with my old FA that had huge patches of sun-lit white for the meter to cue off of. It nailed all of them. (the FA was the first camera Nikon made with a matrix meter) This was while I was in the midst of a horde of angry demonstrators on the Mall and I had no intention whatsoever of fiddling with my camera.
I used to spotmeter and shoot aperture priority. Now I shoot AF(locked on a separate button from the shutter release)/program/matrix on both my F100 and my D100. If I want to open up the aperture it's a thumb-dial away. Most importantly, it allows me to be more spontaneous, and I get more and better shots. Take advantage of what your manufacturer has built in, and only do extra labor when you have to in order for your tools to fill your needs. (IMHO of course)
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thomaskeefer
Mar 14, 2003, 6:37 PM
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Thanks alot! I think that I am going to do some local experimentation with the different slide films..
Thanks again!!
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krillen
Mar 18, 2003, 4:02 PM
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Would using a Circualr Polarizer help with reflected light as it does on water? Or does snow not polarize light when it refelcts it?
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jenna
Apr 14, 2003, 5:42 PM
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a handheld meter is a great investment. there are alot of situations (snow...) that are hard to eyeball. if you get a meter that you can hold right next to what you are shooting, or in front of your camera a ways (scenery) it helps a ton
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drkodos
Apr 14, 2003, 5:54 PM
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As stated above, snow with delicate texture in sun is usually two zones above middle grey on B & W systems. With color, you also need to check the slide film istelf with regard to how it renders UV light. Different manufacturer's brands can give a "warmer" ( pumps up the reds, yellows) or "colder" (great performance with blues) feel. Films that love "cold" light tend to do better at catching the world the way we "see it" in Alpine settings.
Add to that the long standing ethos that slide film should be UNDEREXPOSED a little to begin with and it gets complicated. If you are going to show slides, it's nice to have them a little "dense" (underexposed). If you are looking to make copies such as cibachromes, or using to publish, you may have to be exactly on to maybe 1/4 stop OVER exposed.
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trkrunner03
May 6, 2003, 12:39 AM
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Yeah it really helps to overexpose but it can sometime be hard to judge. There is a set of reference cars for determining hte amount to over and underexpose, it is called the Chromazone reference cards, can be bought onlin at photographer Charles Campbell's web site, just do a webcrawler search for him he is probably like the 4th entry that comes up. Also if the foreground is brighter than the background or vice versa (basically if there are 2 distinct areas of different readings, take the readings with a spot meter, they can be evened out with a Tiffen .3 or .6 ND grad filter in a cokin P series filter holder, this takes some practice but yields good results). Hope this helped, if you need any info about Grad filters or where to find the reference cards email me
Dave
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mtman
May 11, 2003, 6:03 PM
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i have used a polarizing filter on snow with B&W film and it helped a lot and i did not under expose the film, but when you are in lots sun you will need to stop your camera down some.
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extrememountaineer
May 12, 2003, 11:35 PM
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I use a graduated dark gray filter and that seems to take care of the glare coming off the snow and the meter seems to compensate well. The filter is actually meant for contrast in landscapes but works well for evening out the exposure.
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