Continuing my series on our upcoming search for a downed Douglas B-18 bomber in Alaska^* (13 more days to go!), I've started to think about the angle we should use to "look down" at the terrain. This is especially important because I will be mounting go-pro like cameras on the airplane to capture what we "see" on the ground as we go. I will do this with this handy tie-down mount I came across:

This mount allows the camera's to be positioned at any downward angle. I wouldn't think that either straight down or straight ahead would be optimum...I would assume a good angle would be somewhere in between.

Obviously this question has some relation to photography, and I may also post this question to Photography.SE. However, I would also assume there are a great number of pilots or other professionals with experience searching from airplanes/helicopters for things on the ground.

So my question is, what is the best angle (relative to straight ahead) to search for something on the ground.

Keep in mind that I will be searching over glaciers around an active volcano in partially snow covered terrain.

_{* Related posts: Where can I find more information about my grandfather's crashed B-18a bomber on Mt. Redoubt Alaska? and What navigational aid(s) would WWII bomber pilots have used while flying in instrument conditions?}