Sounds like an interesting project. What is your subject? Night or day? or both.
I am curious on what device, cable setup you are using for the intervals, intervoltmeter? I had looked at doing some of these with my old P45+, but never found anything that allowed an interval timer for the Mamiya DF.
Have you figured in the mandatory dark frame the 180 will shoot? For every 3 second exposure you will have a 3 second dark frame so total exposure time is cut in half from 12 to 6 hours, (if I am figuring this correctly?)
I am wondering if the back will get too hot in the time frame, and get a bit noisy, even with the dark frame.
As for laptop, I can't think of any machine that will run for 12 hours, but I may have missed one. The older 2nd gen 15" Macbook pro I have on the mac side will get about 3.5 hours in a push, that's with the screen way down and no other app running. Are you tethering to run Capture One? as Capture one is both processor intensive and ram intensive, at least when it's processing a file, not sure about tethering for long periods of time.
You might have to get an external battery solution like the ones the hypershop sells, as they make several that will add quite a bit of run time, or hook up to a 12 volt car battery with a converter, however this will limit your range due to the weight of the car battery. You have a good concern on time as you would not want the laptop to go into suspend mode, sleep or anything else due to low power as I guess the session would stop.
What software are you putting such a large time lapse together with? I regularly stack 35mm raws up to 1.5 hours in Photoshop using the "stack" modes that are included in CS6, (and can still be downloaded for CS5 from Dr Browns website) but you need the extended version of CS5. This would be a huge stack in converted raws even 8 bit.
Paul Caldwell
