Quote Originally Posted by polyglot View Post
While Acros holds up better than TMY2, the exposure duration for TMY2 at EI400 will always (for exposures shorter than one night) be shorter than for Acros. But you'll get less contrast-increase from the Acros.
I suspected as much. Thanks for the confirmation. But Acros does provide not only the lack of contrast increase but simplicity - just meter and shoot out to two minutes, and add 1/2 stop for 2 minutes up to 1000 seconds (16 2/3 minutes.)