In my opinion, medium format digital is a non-starter for aerial work. I recently flew more than 8 hours in a helicopter over the Okavango Delta in Botswana, and on really sunny late afternoon sessions I would be at ISO 800, 1/1000 to 1/1500 at f/4.5 to about 5.6. I refuse to shoot during the middle of the day, so I am obviously going to get less light in the last few hours of direct sunlight. If there was even a hint of clouds, my ISO would be at 1000 or 1250, hoping for at least 1/500 speeds.
if you are serious about shooting aerials with a MFDB setup, you really really need a gyro from Kenyon Labs. You need to cap your ISO at 100 or 200 on your back, and see what you can get shooting wide open. My personal slowest shutter speed target is at least 1/1000, but I tend to fly low, meaning my subjects are moving faster relative to my camera position than if I were flying higher up.
Michael and I will be back in the delta doing aerial work with our workshop in September, and I am giving through to bringing my Mamiya outfit with a P30. I will only consider it if I also bring a stabilizer. I am not sure it is worth it, since my 1DsMk3 is much easier to handle, has better higher ISO characteristics and has more zoom lens options for better framing of my subjects.
