10-08-2010, 05:34 PM
A faster lens can also mean faster auto focus in low light situations. On certain cameras, a 2.8 lens will focus in a situation where an f4 lens will not. Situations like this are very common in shooting weddings. I have shot a wedding that was lit primarily by candles...talk about a focusing nightmare.
Also, I would not be surprised if the 2.8 lens is sharper at f4 than the f4 lens is at f4 (wide open).
Also, I would not be surprised if the 2.8 lens is sharper at f4 than the f4 lens is at f4 (wide open).