Re: light meters

[Ivo Busko <busko at stsci_edu>]

jgarden2000 at juno_com wrote:

> 
> > I've often idly wondered if those light meters used in professional
> > photography could somehow be made waterproof...
> >
> >  - Erika
> 
> It shouldn't be too hard to put a mirror on the bottom of a tank angled
> at 45 degrees and stick a light meter up to it on the outside of the
> glass...
> 
> William

This won't work. Photographic light meters measure diffuse light. You
should
use a white matte surface instead of a specular reflector. Search the
APD archive, 
I've posted the procedure I used to estimate the light level at the tank
bottom 
using a SLR camera and a white china plate. 

- Ivo Busko
  Baltimore, MD

  "Buy a fish, Save a tree !"
  Project Piaba: http://www.angelfire.com/pq/piaba/