600mm f/11 or 800mm f/11 - which one would you buy?

Colin46 wrote:

I think iso tolerance must be subjective, I’ve never been happy with any camera over 3200 for birds and fine feather detail. Topaz mask AI does an incredible job with high iso images but I prefer to not have to use it.

Definitely, but it does depend on the camera as well, and the 1D-series has always been Canon's flagship in this area, although a lot of birders do seem to prefer the 7D, so there's multiple angles of YMMV there.  I'm personally quite happy to go to ISO 6,400, but after that I'm starting to give serious thought as to how I really want to balance DoF, ISO, and shutter speed.

i will stick with the big guns for now until canon release something similar to Nikon’s 500 f5.6 pf. A 600 f5.6 DO would be amazing and something I would definitely go for.

I'm not seeing any personal use for either of these either,I'm too used to at least have the option of using a shallow DoF to separate the subject from the background, but for those on a budget a relatively compact 600mm or 800mm that at least provides a shot without breaking the bank could be just the ticket.

That said, I am also very interested to see how well Canon has developed their DO tech since the 400mm and 70-300mm.  There was quite a bit of interest in DO versions of the EF mount lenses, so if these f/11 lenses are intended to be the superteles for those on a budget, then f/4 and/or f/5.6 DO versions of the big guns might sell quite well to pros who need a more compact and lighter solution.

Andy