Originally posted by rvannatta I"m sort of thinking that they started with by looking at what an 600/f5.6 would require, and then decided to trade some focal length for some speed. At least I hope so. as an owner of a A*600/5.6 I will be trying really hard to find an excuse to buy this lens, but it will be hard
if its just a crippled version of the A* that I have.
A slower lens isn't a crippled one.
IMHO, fast lenses like 300/2.8 or 600/4 are a thing of the past. Not because they are expensive (they are). But because modern bodies with their ISO capabilities and SR simply don't need it to a degree that the burden to carry and handle them is justified. Sport events from a predetermined position using a tripod may reain the only exception. But those arevTV events with good light, so ...
Assuming the lens is tack sharp fully open, I consider F5.6 (or F5.4 if an AF TC requires it) to be the new sweet spot.