The review is very good, and I appreciate the time that Bryan put in to the review.

@ Scully I think if the 800 v 600 is based only on the extenders you could make the same argument that the 500mm would do as well, it looks very good at 1000mm vs the 800 at 1120. http://www.the-digital-picture.com/R...mp=3&APIComp=1

From what I have seen and read so far, I was thinking the comparison might be made that a 600mm might be the better choice over a 800mm for the reasons Bryan expressed. In fact it was one of the questions I was curious about, how the 600mm would stack up with the extender against the 800mm. The charts at 840mm do look very good.