birdforthought said:Great post and I know its old but.... I have a somewhat opposite question. I currently have the Canon 100-400 Mk I (on a 7D mkI). Yes both 1st generation. I really like this lens/body combination. However, I'm now looking for a more range and of course better low light capability (I photo only birds).
So... without spending $11K what would be the next lens in addition to the 100-400 MkI
FYI: I also have the 1.4x TC version 1 but rarely ever use it
your situation is similar to what I went through.. had a 7D Mk1 and a 100-400 sigma (not the canon, but it died to excessive rain). I purchased the 80D as interim due to certain features and I recently purchased the Sigma C 150-600...
The 80D is cost effective and a significant leap over the 7d Mk1 on many levels, though I do miss the joystick and the fps... but I find way more keepers with the 80D and better recovery.
The 150-600mm is really quite sharp, though I find from time to time it seems to get stuck hunting for focus. I also tried the 150-600 with the sigma 1.4x TC (thinking it would only take sigma, but canon works) on the 80D, but found images got too soft and autofocus worked only on centre and was slower than useful. I may continue to play to find a balance, but I regret buying the sigma TC and felt it was a waste of $... but the 150-600 has been worth it and a cost effective alternative to the higher end canons (they are a bit better, but that price!). Yes I was seeing it was possible to get equivalent to 950mm ;-) (600 x 1.4tc x 1.6crop)