This is the perfect bag for the Canon 300 f/2.8. You can fit a 1 series body attached to the lens into the bag (hood reversed). I had searched high and low for the right bag for this lens. Lowepro just didn't make the right fit for me.

If you are from Canada and looking for this bag don't bother trying Vistek. They are listed as a retailer but after several calls to them they just wouldn't help.

I ordered the bag through Photoco in Pointe Claire (Montreal) Quebec. They have a rather non-descript website but if you need a bag of any sort, this is the place to go. It took longer than I liked but they did come through.

http://www.tenbagear.com/products/2000_01_ll300.asp