Archived posting to the Leica Users Group, 2004/04/29

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Subject: [Leica] Light meters
From: red735i at earthlink.net (Frank Filippone)
Date: Thu Apr 29 20:26:27 2004

Jim,  there are 2 categories of meter cells.... the CDS ( cadmium sulfide)
Cells and the silicon photodiode cells.  What 's the difference?

CDS Cells generate their own electricity, and do not need a battery.
However, the cell ( contacts) eventually oxidizes, and when that happens,
the cell loses accuracy and the only way to fix it is to replace the cell.
Examples very familiar to all of us ( old farts) is the Weston Master meters
and some of the Sekonics.  One big advantage is that they are very much in
tune with film color sensitivity.  More so than the Silicon cell meters.

Silicon photodiode cells need a battery to work.  They are basically
bulletproof from anything other than dropping them.  They will last for
years and years before they need any repair.  ( Calibration is another
issue... once in a while they do age a bit and need a tweak).  Lunasix, and
most of the meters made today are of this variety.  The Weston Ranger meter
is also of this type.

You want reliability and longevity?  get a Silicon cell meter that requires
a battery.  I saw a few Gossens at the store the other day.... digital
readout and really small... About $125.

But back to my question... reflected or incident use?

Frank Filippone
red735i@earthlink.net

As I understand it, the Sekonics don't need batteries.



Replies: Reply from crgrbrts at verizon.net (Craig Roberts) ([Leica] A selenium cell is swell.)
Reply from dante at umich.edu (dante@umich.edu) ([Leica] Light meters)
In reply to: Message from mcintyre at ca.inter.net (Jim McIntyre) ([Leica] Light meters)