Agree. It's not UW. You've to multiply focal length AND Depth of Field by 2.7.
Best for macrophotography. Shot with 105mm macro @ f/11 will give you 2.7 : 1 photo with DOF of 11 x 2.7 or about f/29-equivalent DOF !
Or low cost super-telephoto? The AF-S 300 mm f/4.0D-ED will give your bird size bigger than that price-of-leg&arm AF-S 600 mm f/4.0G-ED.