Exposure in low light.greenspun.com : LUSENET : Large format photography : One Thread
I recently returned from a photo trip to Lone Pine California. I found that my exposures on Fujichrome RVP (Velvia) were on the dark side. I shot 4x5 sheets, loaded myself, at ISO 50. I found that all the exposures made during full "sun up" conditions were spot on exposure wise, but that the shots taken under low light conditions were almost all too dark. I used exposure compensation for a number of "sun up" shots to acount for the polerizing filter I was useing, and found that my compensation was very accurate. On the low light shots (almost all taken after the sun had gone down) I compensated for Reciprocity falure useing the corrections given in Steve Simmons' "USEING THE VIEW CAMERA". I shot some images at exposures of 58 seconds or more, but still found them darker than I wanted them. Has anyone experienced this problem. I would change the ISO, but for the fact that "sun up" exposures were dead on. Do I need to change the ISO only for the low light shots? Is this a regular "thing" with RVP? Are Simmons Reciprocity corrections accurate for RVP? Please Advise.
-- Bill Lindley (firstname.lastname@example.org), January 07, 2000
Did you try some Polaroid shots? I use Velvia @ 50 for still life using natural light and exposures are in the 2 - 4 min range. They come out just fine after I test exposure with Type 52 Polaroid. I use the reciprocity corrections from Simmons' book.
-- VNC (email@example.com), January 07, 2000.
They may have been right on. Your eye sees differently than film and the light you thought you saw was not what the film responded to. Most of the light you saw was most likely blue skylight and that is what Velvia sees least. Velvia is very red/yellow sensitized and sees blues less well. Even though your meter said 12 secs at f22, the film saw 2 mins at f22 because most of the light was from the blue lit sky. Up in the Hills the light dies quickly and there is not much reflected light around. That granite and sagebrush eats light like a famished sumo wrestler. Next time give a stop more exposure after sunset. Learn how your materials respond to different lighting situations before you go on a trip. james
-- Mr.Lumberjack (firstname.lastname@example.org), January 08, 2000.
Try using Velvia at ISO 40 in general. You will be satisfied with more shots.
-- Tom Castelberg (email@example.com), January 08, 2000.
Another piece of advice to prevent losing all those underexposed shots should it happen again is to expose at least 2 sheets identically, process one of them, evaluate the end result and, if underexposed, you can push the second sheet the necessary amount, generally up to one stop.
I generally expose both sheets in a holder the same way. I used to develop all my film from a trip at the same time and invariably would find some exposures that weren't to my liking. I then started processing just one sheet per holder and adjusting the processing for the second sheet if needed. My number of keepers has risen significantly since doing so. The trick is to be able to tell what image/sheet is in which holder. I use Riteways which imprints a number on the edge of each sheet. I write that number on the outside of the holder so I know which holder contains the second sheet of the one that I'm looking at on the light table.
I have found that Velvia pushes up to one stop very well. However, I don't like the color shift and loss of contrast that occurs when I've pulled Velvia any more than 1/3 stop. If you're going to error in your exposures do so on the side of underexposure. Easier said than done sometimes.
-- Mark Windom (firstname.lastname@example.org), January 08, 2000.