Did you miss the fact the Sony has the af motor of the 600 f4 and the extra 50mm really makes the lens much more flexible, add in designed for mirrorless and it's the best light tele around!
btw, seriously, 1/3rd of a stop, maybe I should complain about Nikon and there 20mp sensor lol

Sigma or Tamron for APSC? Forever wait. FF Sigma 350mm would weigh 3 kilos, though the Tamron version might be nice.

so an old tamron gas the same quality? or there is an emount version?!

where to begin...

Look at that pincushion waterline. It's an OK lens, but I could do as well-yes including bokeh-in M43 land for less than a grand, and faster aperture to boot.

'But it's one of the fastest to focus' can only get you so far. Decent, but for a grand? Less than impressive.

Mr Bolton, You'd need a 50-270 3.3-4.6 on m43 to compete, not going to happen in a long long time, how much is a 50-200 2.8-4 plus 1.4x converter!

There is a (for its little asking price) way good 55-250/4.5-5.6 STM Canon APS-C Lens out there. Its almost the only Reason, i do keep my EOS 40D with it. ;) I've seen 1:1 comparsions with the 70-200/F4L USM (w/o IS), and i can't say it's truly or always being better, than this STM.

Because, i've got it shortly, after being released into germany, and because the really good XF55-200mm F3.5-4.8 R LM OIS Fujifilm costs much more, and is being unbalanced then on my X-E1, i'd use this onto a X-T1 or better, but not onto the E1, whileas it would work technically, this setup would being much front-heavy because of the Lens then.

Into short - the Sony Lens *is* being expensive, for an APS-C Zoom especially...but there aren't any comparable eMount APS-C 3rd Party Lenses...maybe Sigma would change this someday into 2020...

A fine evening, and good Light.

I have it. I like it. I see no alternatives listed above. I’m testing it with on-the-wing bird photography. I posted 2 non-flight shots here in my gallery of a peacock and a woodland stork taken in my front yard. These were taken last Friday, the day I received this lens.

You can get terrible amounts of visible noise even at base ISO if the amount of light is scarce.

Use C1, its incredibly detailed and low noise!

I am not sure how a shot taken at low ISO and 350mm would tell us much about the lens more how the sensor performs .

With the lens that slow you are not often going to shoot at low ISO.

I think you may be right, when reviewing lenses (not cameras) it would be useful to see base ISO images. The noise introduced when raising ISO might mask defects. Of course it may not be practical to only do base ISO shots, but something to aim for.

High ISO images have less detail as can be seen from any camera test chart. Wide open shots at low ISO are essential for assessing sharpness. And if you think this is a slow lens and you’ll never be shooting ISO 100 I guess you guys have never shot outside in daylight.

Well the A7RIV is Sonys best APS-C camera. So naturally all APS-C lenses work great on that camera. The question is more how much potential you are waisting. That said with those long lenses I would lie if I would say I wouldn't consider using a smaller APS-C lens if it saves some weight.

A comparison with the 70-300 G would indeed be interesting.

Not to mention that it is slower in crop mode than the 200-600, which you can crop, too.

@ 2JoeA7R2: The "reach" is even more impressie if you use any Sony camera, full frame or aps-c , and crop to MFT format! Then it is whopping 700 mm! You can even crop tighter!

This tells that crop factor is worth nothing when it comes to telephoto reach. It is just ... a crop.

LJ, I just uploaded a couple of shots to my gallery. The quality looks good to me. The FF 70-300 I haven’t shot with, but it is heavier, and costs $100 more, and is 75mm shorter in APSC mode.

Panther: 70-350 is 1.38 lbs. The 200-600 is 4.65 lbs.

J A C S, I just got it, so I don’t know how much slower it is than the 70-350, but it is heavier by the pound as listed above, and $1,000 heavier in my wallet. I’ll be testing it with birds in flight soon. This is my first telephoto, so before I worry about speed in crop mode, I’ll need to see if I can even get bird in frame!

Magnar, yes it is just a crop, sort of. However, an image that fills the frame in crop sensor mode contains more pixels by area than a FF shot enlarged in PS. A more important consideration to me is whether I can get the shot at all. Since the 200-600 weights ~4 times more than the 70-350, I’m not sure if I can hold it long enough to get the shot. I’m 75 and that might not be a consideration for you. But I am sure I could go for longer periods of time with the svelte 70-350.

@ 2JoeA7R2: Why not then go for MFT? Or smaller sensors?

Magnar, as you know, diminishing returns.

@2JoeA7R2 No, it is 50mm shorter. If you get less pixels when cropping full frame to aps-c or not depends on the pixel density of the compared cameras. In fact, the A7RIV has more pixels in APC-C mode than all the Sony APS-C cameras. The A7RIV is the highest resolving APS-C camera from sony as well as the highest resolving FF. If I do not save that much money I would rather get the the 70-300mm because on a FF it is more versatile. The question is how the differ in optical quality.

"75mm more reach" is rather abstract, think 1000-1075 or 25-100...better deal in multiples when calculating this, which translates to 0.167x more reach :)

@ut 2JoeA7R2: With the same physical focal lenght and same camera-to-subject distance, the latent image/projected image on the sensor is the same scale, no matter sensor size. So using a smaller sensor or cropping from a larger sensor at post processing will give exactly the same result, given that pixel pitch is the same.

There is no way the latent image can be larger when using a crop sensor.

So the interesting part is pixel size, not sensor size.

Magnar is correct. Who would suggest otherwise?

@2JoeA7R2 Ok, you have suggested an experiment. Althogh I was very confidend that I knew the outcome I have conducted that experiment. I have used a alpha 7r II. That camera puts out images with the dimensions of 5168x3448 px in crop mode. So I made two images from my little test scene, one in full frame, one in crop. Then I croped the FF image in capture one to 5168x3448 px and compared the result. They are identical. they cover the exact same area. You can switch between those two images and you see no change on your screen. That is what I have expected. Your argument is invalid.

Oh, and regarding the effective reach: I like to compare everything to medium format Film 6×9, just becuse, well... just because I like to.
300mm on small picture has the same reach as 698mm on 6×9. That sounds good, or? And 300mm on APS-C has the same reach as 1060mm on MF 6x9. 350mm on APS-C has the same reach as 1237mm on 6x9. That is a difference of 177mm. Ok, that is considerable, isn't it? Would we like to compare the reach to large format as well? It gets pretty large with 8x10. (3750mm)
You see, that makes absolutly no sense.