Originally Posted by Big Stick
The 100-400 smokes the 150-500 Siggy,in IQ and AF.................


That wouldn't surprise me. What I like about the Sigma is the 750 mm effective reach for the price -- especially compared to anything similar wearing a Nikon name. It's a budget lens, to be sure, but it performs very well on my Nikon for everything that I need a big lens to do. Can't say how it performs on a Cannon.

If you're fixin' to put a hole in something,
make it a hole to remember.