Quote Originally Posted by Daniel Browning View Post
I'm pretty sure that andnowimbroke's question was not for you, EricPvpi. It was for Dave Throgmartin, who said "If you go with the L lens you could find yourself in a position of having to bump ISO beyond where you want to go, or be forced to use a flash, to avoid image blur in less than ideal light." I took that to mean that the I.S. of the 70-300 can help all those issues as long as camera shake is limiting the time value (shutter speed). But andnowimbroke is asking because under many circumstances, the time value is not limited by camera shake, but by other things. In the latter case, I.S. is of no help, and the L lens has potentially one full stop wider f-number.
Daniel was correct on all these things Thanks for clearing up my words or lack thereof.