Again, wrong.
Limiting dof is important but not the reason for f2.8 glass, its shutter speed.
F/4 is plenty shallow for a 300mm lens if you are close enough to fill the frame with it.
so in the end wide open apertures are the offspring of necessity, not artistic need.
In daylight most sports are shot at f/4 to f/5.6, not f2.8 or F1.4.
So again, for sports and wildlife, the increased DOF from APS sensors is welcome, not a detriment...its also areason many professional wildlife photographers prefer aps-c.
Originally posted by cwood Off topic really... but sports photography always happens at the thinest DOF possible. This is the reason we carry around the 300mm lens that weighs 6lb instead of the one that weighs only 1.5lb... Even for an outdoor event in full sun. A sports photographer would never drop down to F4 to get more DOF. The only times I stop my camera down are for landscapes and group portraits.