New 100-400 lenses
p.17 #1New 100-400 lenses
Yep the 70-200 f2.8 II IQ is just OK with the 2X and AF feels a bit sluggish with the A1 II. I would expect the 100-400 f4.5 to be much better.
Jun 05, 2026 at 07:06 AM
p.17 #2New 100-400 lenses
InFocus2014 wrote:
On the other hand, it's hard to say from the initial reviews if it's substantially better than the 200-600mm and 400-800mm. Adding a 4lb and 4k+ lens that doesn't at least fully replace my 200-600mm is a hard sell.
As for the f4.5 aperture, if this lens were a 7lb+ 8k+ f4 zoom, I would not be interested in it at all. So I actually see the f4.5 as an advantage in this case. The only thing that may have added interest to me is if they added an internal TC, even if it added like 1/2 pound to the weight and a few hundred to the cost, if it improved IQ vs an external TC it would have been a value add to me.Not a snowball's chance in hell with the 2x it gets close to the 400-800 IMO. 200-600 + 1.4x is week at 840mm despite being very good sans TC. 100-400 + 1.4x @560 appears about as good as the bare 200-600 @600. I expect 100-400 + 2x @800 to be similar to 200-600 + 1.4x @ 840.
The only Sony lens that does very well with the 2x is the 300 f/2.8. Even the 400 f/2.8 and 600 f/4 with 2x are noticeably weaker than Nikon's equivalents and behind the 300.I agree. I almost sold my 2x converter since, for me, the IQ was unacceptable with every telephoto zoom that I tried it with. Then I acquired the GM 300mm f2.8 and almost had to pinch myself when I critically viewed IQ with the converter, as it was surprisingly good (better than my 200-600mm). I expect to acquire the new 100-400mm, in the near future, but am in no hurry to test it with the 2x converter, as I expect that I will not like the results. As note, I went through a number of 2x converters to select an optimal one.By any chance did you try the 2X TC with new 70-200? AF? Sharpness?Yes. I was not happy with the sharpness. I found better IQ by using the 1.4X and then just cropping.
Thanks for confirming. Looks like 300 is the only lens that produces great result with 2X consistently
Jemini wrote
InFocus2014 wrote
Pixel Perfect wrote
DWOfPaul wrote
I am still having a hard time deciding on this lens. On one hand, I want it. Having a 100-400mm f4.5 sounds great for subject separation and when the light gets low. Add a TC 1.4 and you get a 140-560mm f6.3 that should be just as good as the 200-600mm f6.3. It will also be a bit lighter, have a bit bigger zoom range, and take front and rear filters. Add a TC 2x and you have a 200-800mm f9, which is hopefully as good as the 400-800mm at 800mm (sounds like we need a bit more testing here to know for sure) and will definitely be lighter and have a much bigger zoom range.On the other hand, it's hard to say from the initial reviews if it's substantially better than the 200-600mm and 400-800mm. Adding a 4lb and 4k+ lens that doesn't at least fully replace my 200-600mm is a hard sell.
As for the f4.5 aperture, if this lens were a 7lb+ 8k+ f4 zoom, I would not be interested in it at all. So I actually see the f4.5 as an advantage in this case. The only thing that may have added interest to me is if they added an internal TC, even if it added like 1/2 pound to the weight and a few hundred to the cost, if it improved IQ vs an external TC it would have been a value add to me.
The only Sony lens that does very well with the 2x is the 300 f/2.8. Even the 400 f/2.8 and 600 f/4 with 2x are noticeably weaker than Nikon's equivalents and behind the 300.
Thanks for confirming. Looks like 300 is the only lens that produces great result with 2X consistently
Jun 05, 2026 at 08:26 AM
p.17 #3New 100-400 lenses
It really depends how much light hits the autofocus sensor.
Even now the 70-200/2.8 @ f/2.8 will autofocus more reliably than the 200-600 at 200mm f/5.6
The main difference today is that an A9iii will have better autofocus at f/1.4 over f/2.8 while the DSLR will not improve between f/1.4 and f/2.8
Jemini wrote:
Back during SLR days AF was not reliable after 5.6. So this lens wasn't great with TC. Sigma had similar lens and that was my first long lens with auto focus. Good old days
I would have rather had a 100-300 f4 GM that had really great IQ and was reasonable in size and weight. If Sigma is listening, they made a good one back in the day.
I would still love to see a 500mm f4 but I am pretty sure that will never happen.Given how good the Nikon 400 f/4.5 at crazy light weight, they should do a big brother 500 f/4.5 and I'll bet it's still under 1.7kg. That 1/3rd of a stop makes huge difference to price, size and weight but not so much to IQ.
For me the 70-200 f/2.8 GM II is so good with the 1.4x that the resulting 98-280 f/4 is all I need. I get f/2.8 when needed and 0.49x magnification with the 1.4x!Canon used to make a 500mm f4.5. That was a beauty of a lens, very compact and light compared to the 500mmf4. I'd love to see that made by Sony.The 500/4.5L (3kg) is double the weight of the 300GM..Don’t forget that is a very old lens now, I’m sure modern tech would get that weight down a long way.
Even now the 70-200/2.8 @ f/2.8 will autofocus more reliably than the 200-600 at 200mm f/5.6
The main difference today is that an A9iii will have better autofocus at f/1.4 over f/2.8 while the DSLR will not improve between f/1.4 and f/2.8
Jemini wrote:
Back during SLR days AF was not reliable after 5.6. So this lens wasn't great with TC. Sigma had similar lens and that was my first long lens with auto focus. Good old days
scott f wrote
aCuria wrote
scott f wrote
Pixel Perfect wrote
billsnature wrote
I am a hard pass on the 100-400 f4.5I would have rather had a 100-300 f4 GM that had really great IQ and was reasonable in size and weight. If Sigma is listening, they made a good one back in the day.
I would still love to see a 500mm f4 but I am pretty sure that will never happen.
For me the 70-200 f/2.8 GM II is so good with the 1.4x that the resulting 98-280 f/4 is all I need. I get f/2.8 when needed and 0.49x magnification with the 1.4x!
Jun 12, 2026 at 09:03 AM