Luminance = "Brightness" of your subject (in this case the reflection from your chamber wall.
For proper working of that meter you need a mercury battery. Have you got one??
(Or a well made electronic substitute?)
I just checked my sample:
the needle starts to move about 1/2 stop outside the range of that red digit one has to operate (which I intreprete of sign of good working condition).
And that most extreme position is equivalent to
1h @ f32 @ 100ASA
The sensitivity of that meter would thus be EV +2 .
Last edited by AgX; 05-23-2013 at 07:16 AM. Click to view previous post history.