arbitrage wrote:
A few shots from this morning. Included the 1200mm vs 600mm similar Pintail shots taken just moments apart.
I've been eagerly awaiting hearing about your experience with the new 600 6.3 GM. Lol
How do you feel the AF speed and AF accuracy of your 600 6.3 @ 600mm and 840mm compares to your:
100-400 f4.5 @ 560mm
300 f2.8 @ 600
600 f4 @ 600 and 840mm?
How do you think your 300GM will continue to fit in?
I didn't get a good grasp on how the AF was. My subjects were a little too easy for it. The oystercatchers being the fastest and they aren't that fast. I did shoot a KF but it wasn't very close so wasn't a challenge either.
My gut feeling is the AF vs 300/2x isn't much different. But I will need to test more as I didn't test back to back today with the 300/2x (other than a few in my backyard in the afternoon). In the brief comparison I did I just focused to far trees and near flowers...back and forth....the 300GM you can hear the focus motors working, the 600 was dead silent. Speed and confidence was fairly similar though. No swallows around this time of year to give it a really good test. I will try to get some Dunlin or Turnstone in flight.
I did a quick IQ comparison shooting a bank note between the 600GM and the 300/2x and at 200% view there is the slightest of slightest win for the 600. But it is basically nothing.
So far my conclusion is the main value of this lens is the size/weight advantage even compared to the 300/2x which has always been the size/weight advantage winner up until now. It is a joy to shoot with.
I am still having second thoughts about the 400/4.5 being the better option since it would allow me to shoot at 400.
I need to do some more 600 vs 840 comparisons with the new lens and see if the 840 is gaining anything over cropping. If diffraction is eliminating any advantage to shooting 840 then I might as well go for the smaller and cheaper 400 which we have seen is just as sharp at 560 as the 600 is bare.
My 300mm f/2.8 with a 2x teleconverter is equivalent—or, according to some comparisons, even slightly better—than my 400mm f/4.5 with a 1.4x teleconverter.
The 300mm f/2.8 has a slight advantage when it comes to bokeh.
The 400mm f/4.5 has an advantage in terms of balance.
Regarding autofocus:
I agree with you about the noise from the 300mm f/2.8’s autofocus, whereas the 400mm f/4.5 is completely silent.
Based on my own testing, the autofocus of the 300mm f/2.8 (at 600mm f/5.6) seems slightly better than that of the 400mm f/4.5 combined with a 1.4x teleconverter.
Thanks for your comparison; if possible, I would love to see some JPEGs comparing the 300mm f/2.8 with a 2x teleconverter against your new 600mm f/6.3.
Fabien.
Oct 24, 2026 at 03:20 PM
Previous versions of valmofab's message #17128739 « Sony FE 600mm f/6.3 GM OSS Images Thread »
