Quote Originally Posted by Lee L View Post
A label for 30 minutes on the dial doesn't mean a meter has the best low light measuring capacity. Look for specs that show the lowest EV to which the meter can accurately measure. .... Note that extending exposure time involves a compounding effect, just like compound interest.... Lee
Lee is right. The time means nothing really. I mean, if you are using ASA of .01 that might be a 30 minute exposure in bright sunlight...

So like he says, you need to look for a meter with the lowest EV. The silicon-blue meter in my Canon EF (FD body) goes to EV -3 I believe, which is enough to accurately read a full-moon lit landscape.

However Lee, I'm not sure what you mean exactly by extending time involves a compounding effect. If you are metering 30 minutes exposure, you of course need to apply reciprocity failure compensation, but this new & longer time requires no further compensation (compounding). Right?