Thank you all for the encouraging comments! I really appreciate them. Chango-To answer your question: I'm shooting in complete darkness. I could literally leave the shutter open for hours, and as long as there is not a drop of light from anyone or anything nothing will be exposed in the frame. - I had the climber stop on his ascent, and turn his light out. I set the shutter speed for five seconds. Once I opened the shutter I gave the ok to fire flashes. Once the shutter closed I gave the ok to turn lights on. So during those five seconds there was probably only a 1/3 to 1/2 second of light exposure (I'm guessing). Thanks again everybody.