CCTV for shooting range

[supportnet]

Hi

I have setup a target in my shed and wanted to veiw the target closeup rather than walk backwards and forwards after each shot, so I wanted to install a small CCTV camera on the ceiling about a metre away from the target and have it plugged into a TV 10 metres away.
Calculations on the net say that 1M away from a target 17cm x 17cm to get full screen I would need a lens on the camera min 16mm but 22mm to 60mm varifocal lens would be best.
Anyone in a postion just to see if this is correct.

Cheers

Mark