Long time follower, first time poster.
I'm Cinematographer on a Western Film. We are shooting on a period accurate train with Super16mm SR3 500 stock with Zeiss Super Speeds. We searched the train tracks and found the perfect location to stop the train so we can have as much control/continuity of lighting as possible during the day. It's between 2 huge rock formations and has plenty of tree coverage. The rock formations are very close to the train (average 4-8 feet away on both sides).
These are the readings I get:
Standing in the middle of the tracks between two formations with lots of tree coverage above and full sun: ISO500, f/s48, f 5.6-11, CCT 6460, Lux 1800-2000 average
Sitting on the train in the same exact location with skylight (cloud coverage): ISO500, f/s48, f No reading, CCT3700, Lux 5-10!! (I knew it was going to be very dark but even this was surprising to me)
My question is more geared towards shooting the interiors on the train....when measuring for Lux in a situation like this should I be more concerned about the readings outside or inside the train? My initial thought was to use an M90 as that would be more than ample in this situation from a distance creating a wonderful falloff; but we don't have the budget. Now I am constrained to at most a few 1.2 Arri HMI's combined that I own, or maybe going the route of renting a few Aputure 600d's and using battery power instead of a genny (We are finding out if we can use a genny on the tracks very soon).
My plan was to key talent from upstage outside the train looking in, probably using at least 1/4 CTS and some type of diffusion, then bouncing from inside of train to same key side wrapping a bit to get a bit more level to create the Rembrandt style of lighting, shooting into the shadows; and adding negative fill all behind camera as much as possible. The scene is meant to be dark as the audience knows we are between two rock formations and it is a train robbery. Probably going for an 8:1 at least or even darker ratio on faces.
I like the readings inside the train to an extent because we have almost full control of light. I plan to rig Astera AX1 Tubes in the ceiling to bring level up inside, we have old practicals in the ceiling as well I will most likely outfit with B7C's and try a warm flicker effect. If my 1.2's are used @ flood 23ft through 1/4 CTS and Opal I should be in the 380 Lux area. Or even better IMO if I opt for Aputure 600d with F10 Fresnel Flood 45deg @ 15ft through the same modifiers gives me in the area of 2400 Lux. I still feel I should at least double up on Aputures, and maybe triple up on 1.2's.
This is where my brain is. I haven't shot much film so I don't want to show up, look at monitor and see no levels to work with. And keying from inside of the train just wont look natural IMO.
Ultimately does the key play inside the train if the Lux outside from ambient is higher or the same?