I scored a Leica MC Meter for my M3. First off , I know to look at Butkus manuals for free PDF files, however I work on a military base and there is a lot of restrictions on downloading stuff and I'm very excited to get acclimated with it. Can some one explain if the red dot is for indoor metering and black dot is for outside ?
There are two settings for the MC meter: a high and low range.
The red is the low light sensitivity and the black is the bright light sensitivity range (sunny outside in high noon etc). These two ranges overlap, so basically use the red dot with with a reading from the red scale until you run out of options.
There is a third low light setting but then you need a booster cell which slides onto the meter. The selenium in these meters aren't very sensitive to low light. The meter may or may not work well, depending on how it was stored (dark and dry is good) for example.
The meter can take a bit of time to settle down on the reading.