Needed to do some more exposure testing on the large format camera. Planned to get wide open tests with the 400mm lens on E100. 45 minute shots with a two stop push would be the planned development. I would have liked to do 1 hour shots, but I was unsure how much time that would take. Since it was a work night, I wanted to be finished earlier than I was last Friday.
There were a few clouds early, then these faded away as the sunlight stopped dumping heat into the air. No marine layer. Additionally, the heat from the valley poured up the hill, bathing the lot with mid 80 degree temps and bone dry conditions. No need for a dew heater this evening!
Before the twilight faded, I shot the trix rated at 400.
Some moon shots, some landscape shots.
Shot with the 150mm at f8 then f7 then wide open, all keeping the exposure at 4 seconds.
Then switched to the 400mm and shot wide open at 4 and 6 seconds.
There was one holder where I ended up over exposing the film because I left the lens open. Who knows, with the reciprocity failure, it might actually be the only one properly exposed. The reciprocity failure of trix for a rated exposure of 5 seconds is 18 seconds. Should be interesting.
Anyhow. At least I have some black and white to develop.
The ranger came just after dark. At the time, I was still the only person on the field. Shortly after they left an observer came along and did some visual work. At about 9:30 another car came in, then another. The first car set up closer to me and they did some visual work, too. Their car was set up nicely with dim lighting. The second car, however, wasn't. At least they parked far away. They splashed white light, bright red lights, and green(!) headlamps during setup. Luckily, once they settled down, they were mostly dim.
About 10:30 the first visual observer left, then some time later the second left. For a brief time, there were only two cars on the field. About 11:30 pm a car showed up with lights blazing, fumbled with the lock, then parked. Once their headlights switched off, they settled down. Turned out to be a couple speaking in chinese setting up cots and sleeping bags to observe the night sky.
When I finally left at a little after 12:30, I was able to let the prius drift backwards in neutral (Nice trick to avoid the white backup lights) then crawled out of the lot with no lights. It was a nice show off moment to demonstrate kind light behaviour.
Last night I shot these sequences, all at 45 mins f5.6 and 400mm lens:
- pipe nebula and M8 (30 minutes cut short due to white lights) rotaged back 0
- pipe nebula and M8 with the lps filter rotated back to 0
- Sadr nebula to north american with lps filter. rotated back to 90 - stopped once due to white light
- Same as above.
Tracking was all done via PHD2 with the multi-star guiding. Guiding was rock steady - the graphs were good, most corrections were in the 2 arc second circle. A few stragglers went out to 4 arc seconds. I attibute this to the good polar alignment. I took care to run the alignment while the mount was tracking and was careful about touching up the positioning during the monitor step. Aligned with the red dot finder and was pleased to see the polar alignment model showing 0 error.
I checked the temperature when I got on the road and was surprised that it was still 82F. I had been in a tshirt all night long and during the few times I closed my eyes in the car I found myself getting sweaty from the still air.
During my down time of the exposures, I tried to clean up the trash in the car in an effort to look for misplaced parts. I still can't find the missing lens boards. I may have used them all. I also prepped all my red led lights with new batteries to ensure that I'm not caught unprepared.
Doing some research, I found that the Kodak datasheet for E100 suggests only a color compensation for long exposures. No mention of reciprocity failure. Additionally, Robert Reeves measured the old formula for E100 and gave it a ratio of .95 in evaluation. Shows that a modest half a stop is enough to compensate? Anyhow.
For the Calstar, I may shoot the remaining rolls of e200 in 135 as a piggyback option with a nice bright and sharp lens.