Kind of a random post, but I’ve been putting together a simple video system so that our organist can see the choir director on a monitor located at the organ.  Due to the size of our organ and the angles involved it’s hard for the organist to see much more then the head of the choir director.  In doing this, I needed to figure out what type of lens to use on the camera given the physical constrains of where we can locate the camera on stage

I came across this chart on ebay of all places.  I’ve copied the pertinent information here.  3.6mm seems to be a very common lens, and in our case a 92 degree field of view will work just fine.

1.2mm lens has approximate 185 degree field of view
1.7mm lens has approximate 170 degree field of view
2.1mm lens has approximate 158 degree field of view
2.5mm lens has approximate 147 degree field of view
2.8mm lens has approximate 130 degree field of view
NATURAL HUMAN EYE 2.97 MM
3.0mm lens has approximate 127 degree field of view
3.6mm lens has approximate 92 degree field of view
4.0mm lens has approximate 88 degree field of view
6/0mm lens has approximate 78 degree field of view
8.0mm lens has approximate 58 degree field of view
12 mm lens has approximate 28 degree field of view
16 mm lens has approximate 19 degree field of view
25 mm lens has approximate 13 degree field of view
50 mm lens has approximate 8 degree field of view

The system I came  up with will consist of a “board” type security camera mounted on the choir director’s music stand, or a mic stand directly infront of the choir director.  A BNC cable will connect the camera to an 8″ LCD monitor that will be located at the organ.