Originally Posted by
neuroanatomist
I'm looking forward to my newest lens - in looking over my shots with my EF 300mm f/4<span style="color:red;"]L IS, I find most are at ISOs in the 100-400 range, even in the early morning light. Based on that, I can afford the stop of aperture. I know you like the OOF blur and bokeh of the 300mm prime, but based on the math for a subject at the same distance, 400mm f/5.6 has a shallower DoF than 300mm f/4, and both lenses have an 8-bladed aperture...so, I'm expecting good things in that regard, in addition to the added flexibility of the zoom range.