UPDATE Jan 2020: I finally took the lens out in the field--no more static test shots. The lens performed excellently, and I''ve upgraded my rating from 4 to 5 stars. In my original review, I complained about the bulk. Well, relative to the 500mm and 600mm f/4 monsters...
UPDATE Jan 2020: I finally took the lens out in the field--no more static test shots. The lens performed excellently, and I''ve upgraded my rating from 4 to 5 stars. In my original review, I complained about the bulk. Well, relative to the 500mm and 600mm f/4 monsters that other birders were toting, my kit felt absolutely lightweight. I had no problem carrying and shooting it handheld for a nearly 3-mile hike. I''ve posted some bird shots. The focus speed, accuracy, and lock-on using an A7RIV were much better than my Nikon kit (D850 and 200-500mm zoom). The 200-600mm keeps up well with the 61MP Sensor, and cropping produces excellent results. Not quite at the level of the exotic long primes, but very close for $8-$10k less! For stationary shots (see the egret shots), the lens is amazingly sharp in good light. I couldn''t ask for more from in-body and in-camera IS. However, I wonder if I can extract a bit more sharpness from BIF shots with the OSS turned off. I will experiment. Anyway, for stationary birds, shots up to 400mm are incredibly sharp (as sharp as any 100-400mm lens). However, images are slightly softer at 600mm.
----- (original review follows)
I guess I''m a fan of consumer super zooms (see my reviews of the Nikon 200-500, Sigma 60-600, Tamron 150-600). In short, this is the best so far (not surprising; it''s the latest). However, it''s not a dominant winner. I would not trade the Nikon for the Sony unless I was moving to Sony (which I am). Frankly, I''d pick the Sigma as the best (sharp over its entire range with reasonably fast AF) except that I prefer to shoot handheld. The Sigma is nearly 6 lbs, which is just too big to shoot handheld. The Sony and Nikon are both less than 5 lbs. For me, that pound makes a huge difference.
Sharpness is not a distinguishing factor between these lenses. At 500 or 600mm, throw a blanket over the Nikon, Sigma, and Sony (the first generation Tamron trails all three). I have an excellent copy of the Nikon, and really struggle to see a difference between it and the 600mm lenses. Both the Sigma and Sony provide more resolution at the longest focal length (I think the Sigma marginally more than the Sony, but they''re really close), but differences between the 3 lenses is marginal. Most will be disappointed by how little the additional 100mm buys you. The Canon (and presumably the Sony 100-400 GM) have a certain "crispness" (micro-contrast) at 400mm not present in the Sony long zoom at 600mm. This is not surprising. I expect a bit more for professional-level lenses. The 200-600 is a (very small) step down but does provide noticeably more resolution.
Handling is the distinguishing factor. The Canon (shot on a Sony A7r3) handles like a pancake lens relative to the other behemoths. The IS (image stabilization) locks on like a clamp, and there are few misses. The Nikon''s VR (vibration reduction) also locks on during focus, but seems to jump around during shooting. I get more out-of-focus shots with the Nikon, but still a very high proportion in focus. The Sigma is comparable to the Nikon. The Sony''s OSS trails the pack. It''s OSS Jumps around during focusing and shooting. I get more misses with the Sony than with any other lens. This doesn''t mean the OSS is bad--the target was small and 60-70 meters away, so a very difficult test--, it just means that for best focus, use a tripod. For most normal size targets (small birds will be larger and closer than my test target), the OSS should work just fine.
A lot has been made of the internal zoom, which is nice. But the result is a 12.5 inch package. I think that my focusing difficulties are directly attributable to the length. Even though it''s not extremely heavy, the length makes it hard to hold the kit steady especially compared to the "compact" 100-400. The Canon 100-400mm is slightly more than 8" with adapter. Because the Sony doesn''t telescope, I must extend my left hand further out when focusing. I suspect that the difference in arm extension could be 6 inches, a substantial difference.
Miscellaneous observations: the internal zoom is nice, but handling might be better if it telescoped like other lenses in this class. The other negative is that the bulk might discourage you from traveling with this lens. I love the short throw of the zoom ring. It takes half a rotation to go from 200 to 600mm. By contrast the Nikon takes about two full rotations to go from 200 to 500mm.
Overall, this is a very nice offering for Sony wildlife shooters. It is on par with other lenses in this class, but it is not substantially better. The IQ is excellent, albeit a step down from the quality expected from professional-level and exotic primes but clearly better than the first generation Tamron 150-600mm . A Sony shooter with the 100-400GM would be better served adding a 1.4x TC than buying this lens. The 200600 will just add bulk without increasing your keeper rate or IQ. Nikon shooters have no reason to envy this Sony. The Sony probably has faster AF (I will add comments once I test), but the IQ is comparable. However, for Sony nature shooters who can''t afford the over $3k 100-400GM + 1.4x TC, this is an "affordable" option that will allow you to get shots that were previously unavailable in Sony mirrorless without major compromises. Accordingly, I highly recommend the Sony as an affordable alternative to the exotic primes, but it is not perfect.