NOOOO!!!! The 200mm f/2.0 is discontinued!!!!!

[Joel Eade]

https://www.the-digital-picture.com/...mp=0&APIComp=2


A little difficult to tell in this comparison due to image size differences but it gives some idea about the 800 vs the 600 with teleconverters

[Fast Glass]

I'm referring to wide open IQ especially at the 1200mm'ish range. There the 600mm III has a definite disadvantage.

As with Bryans awesome review, I rarely ever stop down with a super telephoto lens except for a landscapes in ideal lighting. Otherwise it remains open 99% of the time. But that is just me.

Bare lens IQ is good to know for when you can frame it with a 600mm. But that difference to me is very minimal. I care about bigger differences in IQ and for me that would be with a 600mm III with a 1.4x and 2x. Then it levels the playing field and you can see the 800 having a noticeably better contrast. Because the 800mm, 1200mm focal lengths are very useful to me.

Also, comparing the 600mm f/4 at 5.6 is kinda unfair. You would have have to stop down the 800mm one stop as well if you wanted to look at stopped down IQ.

Yeah I know, if you can manage it you get better IQ. But I don't do much setup birding. I like going out and getting wild birds. They don't always let you get good shots up close. So have being able to get a decent 1120mm with only a 1.4x is huge.