Hi people. Sorry to resurrect this thread, but something has been bugging me about this whole EF-800mm thing.
My thinking is that I would be surprised if there is much of a difference in performance between the 600mm f/4 with a 1.4x teleconverter and the "new" 800mm f/5.6. Think about it - the two lenses are actually about the same size (and, apparently the 800mm is lighter). I bet the front element on the 800mm is the same size as (or perhaps even smaller than) the 600mm.
It seems to me that Canon decided that they could make a tarted-up 600mm with a built-in teleconverter and charge a lot of money for it (and sell it to the Bulbmoguls of this world
).
Seriously, these lenses have the same light-gathering ability. The 800mm is just a "magnified" version of the 600. I concede that its possible that Canon have improved the design a bit, or used better materials for the 800, but other than that, the perfomance should be roughly the same.
Now, if Canon came out with an 800mm f/4L, then that really would be special ! It would also be a lot bigger and heavier.
It reminds me of the 300mm f/4L and the 400mm f/5.6L. If you see these two side by side, they are roughly the same size and have the same-sized front element. I'm not sure if anyone has done a comparison between the 400/5.6 and the 300/4+1.4x, but I bet there isn't much of a difference.
Actually, in the secondhand market, you can buy a 400/5.6 for less than a 300/4 and teleconverter !
If I am wrong about this, then I am happy for someone to show me why, but please don't say things like "..but the 800mm will be "sharper"
without some sort of rational explanation to back up your assertion.
Ahh, that feels better. I had to get that off my chest. Rant mode off.
Bye now.