Well, at the risk of repeating, I'll just say most of the people who advise against this combination don't actually own and use it. I have sold thousands of dollars worth of pictures shot on a 1DMKII or an XTiwith an EF70-200mm f/2.8 L IS USM backed by the 2x doubler. The key is your usage and the light.


My pictures are typically sold as 4x6's or 5x7's. If you look at those images in portrait mode on a 24" monitor, the IQ might not be impressive.If your not blowing up 16x20's, this lens combination will work. If you have ever sold a picture to your local paper you know that your 10-megapixel beauty gets printed at 85lpi. That really makes you glad you splurged for "L" glass.


The second key is light. This combination puts you atF/5.6 wide open.It will not work for football under the lights. This is adaylight only combination that keep you from dragging a 400mm f/2.8 around kids soccer fields for 12-hoursat a time.