How to measure and time long exposures at dusk or dawn.

Like Stone, I shoot Acros - especially for night scenes. A few years back several of us got together for a 4am meetup at Sutro Bath ruins on the San Francisco coast. Everyone was shooting digital SLR except for me: I was shooting Acros with a Pentax 67II. The Pentax digital spot meter read "0" everywhere for the EI. I asked Steven who was nearby what he was getting with his camera. "It's a little blown-out at 7 minutes at ISO 100 and f..." Seven minutes on a CCD chip is seven minutes on Acros and all 10 frames turned out well exposed but several were "ruined" by ships suddenly exiting the Golden Gate (you can't see what's coming around the bend) and ships entering turn their lights on well offshore and leave streaks of light across the horizon. Packing a small digital camera solves the exposure problem in those instances: You can get an accurate idea of the correct timing as long as you are using a film like Acros.

zthomas

At "integrating" meter can be created which adds up the exposure. I am unaware of any commercial examples but I made one a long time ago that filled up a capacitor. You could set the dark current separately so sort of compensate for schwarzchild.

"ONE Deardorff, TWO Deardorff, THREE Deardorff...." I find to be accurate enough.:)