I have painted Apollo 15 Commander Dave Scott doing what astronauts do best, photographing million-year-old rocks. I know this may seem like a fun, glamorous, and exciting activity, but it's not as easy as it looks. The problem is that it's impossible to look through a standard camera viewfinder with a helmet on. There is neither extra time nor spare film available for bracketing.

We found that a Hasselblad 70mm camera, modified to meet the vacuum and temperature extremes of space, gave us the best photographs. We attached a handle with a trigger for easy shutter release and mounted the system high up on the chest.

I remember when Pete Conrad and I took our first photographs during simulated moonwalks at Cape Kennedy. When we studied the resulting film, we discovered that many were not pointed accurately, were out of focus, or over or under exposed. Not a pretty sight. But, with each subsequent training session, the photography improved.

I have looked at the photographs from Apollo 15 and they are almost 100 percent perfect. Dave Scott and Jim Irwin put in a lot of careful practice in the months before liftoff, and it paid off handsomely. Dave would later say about his lunar photography, "the photographs, it seems to me, provided us with a testament that transcends time, for we may be photographing the distant past of our own planet."