j1clark@ucsd.edu
Veteran
Lighting
2.5 Light kits (This needs to be various light intensities and softness) I used
3 - 1Ks, 3 - 650s, 3- 300s, 2 - 150s
I had a lot of problem figuring out two things recently when I rented both lights, a Lowell 3 light package, 750, and 2 250's, and a Panasonic HMC150. The lights were way under what they should have been... as hindsight shows... but I was really stumped for exactly how many fc's the lowells were puting out, to estimate whether that was enough or not... it wasn't... and further, even though the Panasonic HMC150 has a IRE indicator, and I calibrated my spot meter to a 18% grey card to an IRE of 50% I was off by at least a 1 or 2 stop value. I haven't had time to recheck my meter relative to my digital stills to see if the meter is just 'off'...
But even from the manufacturer there was no nice way of finding out the effective ISO, as the only parameter was the minimum light, as opposed to 'sensitivity', or the like. I'm suspicious about why the 'low light' value is given, as opposed to a number for a middle value...
Once one has an effective ISO rating, and the fc values, there are a number of charts one can use to estimate F-stop, and whether that's going to work for the shot...
I use the spot meter over the incident meter because then I don't have to worry about whether the reflectivity of the subject is one thing or another. I get a reading of what the reflected intensity is... and then find out the ratios between high and low values. (The spot meter also has a flash mode to check out flash values... unnecessary for film... doesn't have a direct fc read out... darn...).