Spot meter

[Tom Deering <tmd@xxxxxxxxxxx>]

On 10/21/99, Greg Erker wrote:
>>light meter to let me take spot meter readings.  The main part is a
>>piece of 3/8 ID plastic tubing with a tube of shiny mylar slid

Is the mylar in the tube a good idea? Doesn't that let bright light 
outside your spot area bounce off the walls and affect your reading. 
Shouldn't the tube be covered inside with black flocked paper so just 
the circular view at the end affects the reading?

I don't know.  One thing for sure, without the mylar, the light 
coming down the tube would be too dim for my meter to measure.

If you look down the shiny tube, then point it around, the reflected 
light seems to be a duplication of whatever you see out the end. 
There may be other light getting down there, but it seems minimal. 
Try it and see what you think.

I will say that the spot is very narrow, maybe six inches wide at ten 
feet.  The exact measurement is not critical for me.  You could 
adjust this by making the tube longer or shorter.

Tom