Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
p.3 #1Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
robert614 wrote:
Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.That brings up an interesting question. If AF speed is primarily governed by aperture, do the 400mm + 2x @ f9 and 600mm + 1.4x also @ f9 have equal AF speed?
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the...Show more →
Yes, it's mainly governed by the aperture. And also, the T value, alongside with the contrast. In this case, 400+2x has the same F value as 600+1.4x, but it has a lower T value due to extra light loss, and it also has more contrast loss in the 2x TC (more glasses and poor sony coating used on their TCs).
Jack Flesher wrote
My guess is TC’s slower AF response is primarily due to the loss of micro contrast and darker aperture created by them; and in this it makes sense the 2x impairs both more than the 1.4x.Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the...Show more →
Yes, it's mainly governed by the aperture. And also, the T value, alongside with the contrast. In this case, 400+2x has the same F value as 600+1.4x, but it has a lower T value due to extra light loss, and it also has more contrast loss in the 2x TC (more glasses and poor sony coating used on their TCs).
Sep 23, 2026 at 08:32 PM
p.3 #2Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
It would have been nice to compare it with the 300mm GM as well.
Anyway, I’d like to point out that the test was done wide open (TA)... which makes sense to me because that's how they're used most of the time, but it’s equally obvious that any advantages in resolution (like 400 vs 400) would probably change—maybe even reverse—at the same aperture.
As far as I'm concerned, these are a great indication of how they perform with teleconverters (TC)
Anyway, I’d like to point out that the test was done wide open (TA)... which makes sense to me because that's how they're used most of the time, but it’s equally obvious that any advantages in resolution (like 400 vs 400) would probably change—maybe even reverse—at the same aperture.
As far as I'm concerned, these are a great indication of how they perform with teleconverters (TC)
Sep 24, 2026 at 01:50 AM
p.3 #3Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
_MacTwin_ wrote:
It would have been nice to compare it with the 300mm GM as well.
Anyway, I’d like to point out that the test was done wide open (TA)... which makes sense to me because that's how they're used most of the time, but it’s equally obvious that any advantages in resolution (like 400 vs 400) would probably change—maybe even reverse—at the same aperture.
As far as I'm concerned, these are a great indication of how they perform with teleconverters (TC)
I agree 100% with all written here.
Especially the first sentence. I want a 300/2.8
It would have been nice to compare it with the 300mm GM as well.
Anyway, I’d like to point out that the test was done wide open (TA)... which makes sense to me because that's how they're used most of the time, but it’s equally obvious that any advantages in resolution (like 400 vs 400) would probably change—maybe even reverse—at the same aperture.
As far as I'm concerned, these are a great indication of how they perform with teleconverters (TC)
I agree 100% with all written here.
Especially the first sentence. I want a 300/2.8
Sep 24, 2026 at 01:55 AM
p.3 #4Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Jemini wrote:
robert614 wrote
Jack Flesher wrote
My guess is TC’s slower AF response is primarily due to the loss of micro contrast and darker aperture created by them; and in this it makes sense the 2x impairs both more than the 1.4x.Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the final aperture without opening up. Does, for example, stopping down a 200-600mm from f6.3 to f7.1-f8 for extra sharpness hurt your AF speed?
Definitely not. Camera focuses using max aperture for focusing. Stops down only when camera takes the picture. Otherwise DSLR/SLR wouldn't focus at all when stopped down below 5.6
On Sony mirrorless there is an option in the menu for the AF to open up to max aperture when focus with a caveat that it slows down frames per second.
So in standard it focus with the set aperture, not wide open.
Sep 24, 2026 at 07:27 AM
p.3 #5Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
biggles2002 wrote:
Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.That brings up an interesting question. If AF speed is primarily governed by aperture, do the 400mm + 2x @ f9 and 600mm + 1.4x also @ f9 have equal AF speed?
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the final aperture without opening up. Does, for example, stopping down a 200-600mm from f6.3 to f7.1-f8 for extra sharpness hurt your AF speed?"And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?"
Definitely not. Camera focuses using max aperture for focusing. Stops down only when camera takes the picture. Otherwise DSLR/SLR wouldn't focus at all when stopped down below 5.6On Sony mirrorless there is an option in the menu for the AF to open up to max aperture when focus with a caveat that it slows down frames per second.
So in standard it focus with the set aperture, not wide open.
Thanks for the info. Didn't know this. I almost always shoot wide open. But will check the impact..
Jemini wrote
robert614 wrote
Jack Flesher wrote
My guess is TC’s slower AF response is primarily due to the loss of micro contrast and darker aperture created by them; and in this it makes sense the 2x impairs both more than the 1.4x.Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the final aperture without opening up. Does, for example, stopping down a 200-600mm from f6.3 to f7.1-f8 for extra sharpness hurt your AF speed?
Definitely not. Camera focuses using max aperture for focusing. Stops down only when camera takes the picture. Otherwise DSLR/SLR wouldn't focus at all when stopped down below 5.6
So in standard it focus with the set aperture, not wide open.
Thanks for the info. Didn't know this. I almost always shoot wide open. But will check the impact..
Sep 24, 2026 at 07:50 AM
p.3 #6Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever so slightly better scripted for my use .I will wait for prices to level out and i am just about to purchase the 50-150mm f2 which is another arm and leg purchase ,but i can see my 400-800mm going in part ex for 600mm f6,3 or is that 400mm f4.5 with 2x .
Sep 24, 2026 at 08:56 AM
p.3 #7Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Xraypaul wrote:
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever...Show more →
Purchased the 300 about a week before the rumor mill started posting about the new lenses. I shoot around 600+ most of the time with a solid mix around 400mm as well.
I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
Hatch
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever...Show more →
Purchased the 300 about a week before the rumor mill started posting about the new lenses. I shoot around 600+ most of the time with a solid mix around 400mm as well.
I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
Hatch
Sep 24, 2026 at 09:12 AM
p.3 #8Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
hatch1921 wrote:
Purchased the 300 about a week before the rumor mill started posting about the new lenses. I shoot around 600+ most of the time with a solid mix around 400mm as well.
I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or...Show more →
I think there will be a quite a few 300 2.8's for sale.
Xraypaul wrote
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever so slightly better scripted for my use .I will wait for prices to level out and i am just about to purchase the 50-150mm f2 which is another arm and leg purchase ,but i can see my 400-800mm going in part ex for 600mm f6,3 or is that 400mm f4.5 with 2x .I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or...Show more →
I think there will be a quite a few 300 2.8's for sale.
Sep 24, 2026 at 10:08 AM
p.3 #9Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Donzo98 wrote:
Purchased the 300 about a week before the rumor mill started posting about the new lenses. I shoot around 600+ most of the time with a solid mix around 400mm as well.
I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
HatchI think there will be a quite a few 300 2.8's for sale.
Then I hope there are a lot of happy buyers I really like the lens, I'm keeping it... others might not feel the same way... which is fine of course.
hatch1921 wrote
Xraypaul wrote
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever so slightly better scripted for my use .I will wait for prices to level out and i am just about to purchase the 50-150mm f2 which is another arm and leg purchase ,but i can see my 400-800mm going in part ex for 600mm f6,3 or is that 400mm f4.5 with 2x .I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
Hatch
Then I hope there are a lot of happy buyers I really like the lens, I'm keeping it... others might not feel the same way... which is fine of course. Sep 24, 2026 at 10:20 AM
p.3 #10Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
robert614 wrote:
Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.That brings up an interesting question. If AF speed is primarily governed by aperture, do the 400mm + 2x @ f9 and 600mm + 1.4x also @ f9 have equal AF speed?
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the final aperture without opening up. Does, for example, stopping down a 200-600mm from f6.3 to f7.1-f8 for extra sharpness hurt your AF speed?"And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?"
Definitely not. Camera focuses using max aperture for focusing. Stops down only when camera takes the picture. Otherwise DSLR/SLR wouldn't focus at all when stopped down below 5.6I know that was true in the DSLR days. Even the early days of mirrorless. But I believe (correct me if I’m wrong) that modern mirrorless bodies focus at the final aperture without opening up during AF
Correct. In single shot AF (AF-S) it depends on body, lens, available light and settings, but during AF-C the lens stays at the set aperture.
Jemini wrote
robert614 wrote
Jack Flesher wrote
My guess is TC’s slower AF response is primarily due to the loss of micro contrast and darker aperture created by them; and in this it makes sense the 2x impairs both more than the 1.4x.Side note. I think it’s nuts for anyone to buy a third party 2x for any Sony lens that accepts the Sony converters, but that’s me.
And if we want to get even nerdier about it, does stopping down a lens for better sharpness actually hurt AF performance slightly?
Back in the DSLR days (also in the early mirrorless days) the lens would open the aperture wide open during AF and only close down to the working aperture when taking the photo. So stopping down wouldn’t affect AF
But now that mirrorless cameras focus at the final aperture without opening up. Does, for example, stopping down a 200-600mm from f6.3 to f7.1-f8 for extra sharpness hurt your AF speed?
Definitely not. Camera focuses using max aperture for focusing. Stops down only when camera takes the picture. Otherwise DSLR/SLR wouldn't focus at all when stopped down below 5.6
Correct. In single shot AF (AF-S) it depends on body, lens, available light and settings, but during AF-C the lens stays at the set aperture.
Sep 24, 2026 at 10:45 AM
|
p.3 #11Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Donzo98 wrote:
I think there will be a quite a few 300 2.8's for sale.
I sold mine. I've only been using the 300 with the 2X occasionally handholding due to its lighter weight and smaller size versus the 100-400 f4.5 + 1.4X. The new 600 will blow either of those combos away from a size/weight standpoint. I'll take my chances that the 600 has equal IQ / AF speed to the 300 + 2X. The 100-400 certainly did not disappoint. I think all the new recent GM lenses are awesome. Sony has the secret sauce working with the new designs.
I think there will be a quite a few 300 2.8's for sale.
I sold mine. I've only been using the 300 with the 2X occasionally handholding due to its lighter weight and smaller size versus the 100-400 f4.5 + 1.4X. The new 600 will blow either of those combos away from a size/weight standpoint. I'll take my chances that the 600 has equal IQ / AF speed to the 300 + 2X. The 100-400 certainly did not disappoint. I think all the new recent GM lenses are awesome. Sony has the secret sauce working with the new designs.
Sep 24, 2026 at 10:45 AM
p.3 #12Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
hatch1921 wrote:
Purchased the 300 about a week before the rumor mill started posting about the new lenses. I shoot around 600+ most of the time with a solid mix around 400mm as well.
I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
HatchI think there will be a quite a few 300 2.8's for sale. Then I hope there are a lot of happy buyers I really like the lens, I'm keeping it... others might not feel the same way... which is fine of course.
I am hoping to be one of those happy buyers 😄 I'm looking to upgrade from my 200-600 and have pre-ordered the new 600mm. I would like the new Sony 100-400 to go with it, but not crazy about its price or weight, and I already have the Sigma 100-400. Already have the 1.4tc, so yes having 300 f2.8, 420 f4, 600 f6.3, and 840 f9 at 5.5lbs will be a great telephoto lineup for me.
Donzo98 wrote
hatch1921 wrote
Xraypaul wrote
Its funny really so many sony shooters bought the 300mm f2.8 to shoot at 600mm f5.6 in a lightweight telephoto ,do not get me wrong many also purchased for the 300mm f2.8 , that as i always said is the main part if your 90% photographing at 600mm then the 300mm makes little sense ,its one of the reasons i purchased the sigma 500mm which is optically superior if you factor in t/c ,but this now a dead horse also now the new primes have arrived exciting times the 400mm f4,5 looks superb but then the 100-400mm f4.5 is ever so slightly better scripted for my use .I will wait for prices to level out and i am just about to purchase the 50-150mm f2 which is another arm and leg purchase ,but i can see my 400-800mm going in part ex for 600mm f6,3 or is that 400mm f4.5 with 2x .I purchased the 600 F/6.3 based on weight/size alone.
300+ TCs gives me 300mm f/2.8, 420 f/4.0 with no degradation to the performance of the lens or the files, that I can tell. If needed, 600mm at F/5.6 but this where I'll likely leave the 2x off the 300. The new 600 will replace my 200-600 and for more reach I can add the1.4x to the 600 or shoot the 400-800 with or without the teleconverters. I just shot the 400-800 with the 2x on the other day and couldn't believe the results were really nice.
The 300/600 combo with TCs is a lightweight setup I'm looking forward to using. I didn't buy the new 400 as the 300+1.4 is stellar.
I doubt I'm the only one that's hanging on to the 300mm+TC combo and coupling it with the new 600mm... it's a hard to beat setup IMO.
Enjoy the day.
Hatch
Then I hope there are a lot of happy buyers I really like the lens, I'm keeping it... others might not feel the same way... which is fine of course. I am hoping to be one of those happy buyers 😄 I'm looking to upgrade from my 200-600 and have pre-ordered the new 600mm. I would like the new Sony 100-400 to go with it, but not crazy about its price or weight, and I already have the Sigma 100-400. Already have the 1.4tc, so yes having 300 f2.8, 420 f4, 600 f6.3, and 840 f9 at 5.5lbs will be a great telephoto lineup for me.
Sep 24, 2026 at 11:23 AM
p.3 #13Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
James Burden wrote:
I'm patiently waiting to see 840/f9 actual photos of wildlife not test charts.... 🦁🦜🐻
Fabian Fopp did some testing of this and results looked good. Heck he posted 600 + 2x image of a crackle bird and it looked very good despite being f/13 and well into diffraction territory. H even stated the 600 + 1.4x is sharper than the 400 + 2x, but margin is lot large at all.
apb80 wrote:
I am hoping to be one of those happy buyers 😄 I'm looking to upgrade from my 200-600 and have pre-ordered the new 600mm. I would like the new Sony 100-400 to go with it, but not crazy about its price or weight, and I already have the Sigma 100-400. Already have the 1.4tc, so yes having 300 f2.8, 420 f4, 600 f6.3, and 840 f9 at 5.5lbs will be a great telephoto lineup for me.
I just got my 100-400 and that is replacing the 200-600. Feels a lot nicer in the hand and lighter than you'd think. Better balanced to and OS is miles better. In next 6 months or so I'll get the 600 f/6.3 purely for birding. 100-400 is so versatile and optically very good as a 140-560 f/6.3 I'll use it for many things.
Edited on Sep 24, 2026 at 09:31 PM · View previous versions
I'm patiently waiting to see 840/f9 actual photos of wildlife not test charts.... 🦁🦜🐻
Fabian Fopp did some testing of this and results looked good. Heck he posted 600 + 2x image of a crackle bird and it looked very good despite being f/13 and well into diffraction territory. H even stated the 600 + 1.4x is sharper than the 400 + 2x, but margin is lot large at all.
apb80 wrote:
I am hoping to be one of those happy buyers 😄 I'm looking to upgrade from my 200-600 and have pre-ordered the new 600mm. I would like the new Sony 100-400 to go with it, but not crazy about its price or weight, and I already have the Sigma 100-400. Already have the 1.4tc, so yes having 300 f2.8, 420 f4, 600 f6.3, and 840 f9 at 5.5lbs will be a great telephoto lineup for me.
I just got my 100-400 and that is replacing the 200-600. Feels a lot nicer in the hand and lighter than you'd think. Better balanced to and OS is miles better. In next 6 months or so I'll get the 600 f/6.3 purely for birding. 100-400 is so versatile and optically very good as a 140-560 f/6.3 I'll use it for many things.
Edited on Sep 24, 2026 at 09:31 PM · View previous versions
Sep 24, 2026 at 09:24 PM
p.3 #14Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
I'm ready for the 300mm dump so I can get one for like 4200 bucks.
Sep 24, 2026 at 11:33 PM
p.3 #15Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
So about that amazing 300GM we've all come to love over the past 2 years....where does it stand now with these two new lenses entering the decision tree?
If you need 300mm @ f/2.8 then for sure it is the way to go.
But everything else we've learned so far about the new 400 and 600 sort of show it isn't the way to go anymore.
AF is the only thing we don't really have a good grasp on yet and understandably as it is hard to compare without prolonged shooting and most reviews didn't shoot long enough IMO to really know.
If we list advantages of the 400 and 600 over the 300 it is hard to say the 300 is still the way to go:
1) Cheaper...significantly...you can buy both new lenses for less than the 300
2) Lighter...significantly especially if we take weight of 300/2x vs 600
3) Smaller to pack
4) Slightly better IQ for 600 vs 300/2x. We've also seen 400/1.4x match or best 600 in most comparisons which means it should also slightly best 300/2x.
5) Ability to get to 800/840mm. Both lenses can do this and appears they do it equally well. 300 can only do it with stacked TCs that lose infinity and even mid-range focus (next to useless IME).
So where does the 300 still make sense:
1) If you need a 300/2.8 lens
2) Better max magnification at 600mm....but the new lenses have higher magnification at 800/840 than the 300/2xTC does at 600.
3) 2m vs 2.5m MFD
To be honest, I feel that unless you need that 300mm, the most versatile lens right now is the 400/4.5.
BUT...the big question is how the AF compares between all these options. Which combo is best at 560/600? Is the 400/2xTC worse than the 600/1.4TC? How does the 300/1.4TC compare to the 400 bare? Answers to those questions could certainly sway my conclusion.
I'm still probably going to run a 300GM and 600/6.3 setup as I do have use for the 300/2.8 at 300. But an alternative for me could be a 400/4.5 with a 70-200/2.8II. I don't see myself using the 100-400/4.5 as much as I hoped I would...that lens may be on the chopping block. The 600/4 always sticks around until Sony releases a 400/2.8TC lens
If you need 300mm @ f/2.8 then for sure it is the way to go.
But everything else we've learned so far about the new 400 and 600 sort of show it isn't the way to go anymore.
AF is the only thing we don't really have a good grasp on yet and understandably as it is hard to compare without prolonged shooting and most reviews didn't shoot long enough IMO to really know.
If we list advantages of the 400 and 600 over the 300 it is hard to say the 300 is still the way to go:
1) Cheaper...significantly...you can buy both new lenses for less than the 300
2) Lighter...significantly especially if we take weight of 300/2x vs 600
3) Smaller to pack
4) Slightly better IQ for 600 vs 300/2x. We've also seen 400/1.4x match or best 600 in most comparisons which means it should also slightly best 300/2x.
5) Ability to get to 800/840mm. Both lenses can do this and appears they do it equally well. 300 can only do it with stacked TCs that lose infinity and even mid-range focus (next to useless IME).
So where does the 300 still make sense:
1) If you need a 300/2.8 lens
2) Better max magnification at 600mm....but the new lenses have higher magnification at 800/840 than the 300/2xTC does at 600.
3) 2m vs 2.5m MFD
To be honest, I feel that unless you need that 300mm, the most versatile lens right now is the 400/4.5.
BUT...the big question is how the AF compares between all these options. Which combo is best at 560/600? Is the 400/2xTC worse than the 600/1.4TC? How does the 300/1.4TC compare to the 400 bare? Answers to those questions could certainly sway my conclusion.
I'm still probably going to run a 300GM and 600/6.3 setup as I do have use for the 300/2.8 at 300. But an alternative for me could be a 400/4.5 with a 70-200/2.8II. I don't see myself using the 100-400/4.5 as much as I hoped I would...that lens may be on the chopping block. The 600/4 always sticks around until Sony releases a 400/2.8TC lens
Sep 25, 2026 at 04:52 AM
p.3 #16Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
If you do any sort of safari, then 300 is the most versatile. If you only do birding, then sure, 600 is the way to go. For me, 300 + tc and 600 makes the most sense.
Sep 25, 2026 at 07:16 AM
p.3 #17Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Wouldn't the 100-400 F4.5 GM be the most versatile for safari?
Sep 25, 2026 at 07:24 AM
p.3 #18Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Sony 300mm GM release 2 years ago game changing but it didn't pitch my interest until now, how does Sony pull that off I'm really gobsmacked well done Sony. I am now really considering going full Sony and selling all my Canon gear my ideal setup below:
A1 II
14mm 1.8
Tamron 25-200mm
300mm GM
600mm 6.3 GM
1.4x and 2x TC
I think I am going to do it as I'm getting some cash back from selling all Canon
A1 II
14mm 1.8
Tamron 25-200mm
300mm GM
600mm 6.3 GM
1.4x and 2x TC
I think I am going to do it as I'm getting some cash back from selling all Canon
Sep 25, 2026 at 07:26 AM
p.3 #19Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
It's probably a "me thing" but I believe it could be a bit different from the perspective of one who doesn't have an 'Excalibur' lens, just waiting in the cabinet, when it's needed to get THE shot. Then, I imagine having that Excalibur lens, one could more easily consider 'settling' for a lighter/ slower lens to add to the kit.
For people like me, who salivate over those shots we see gotten by those of you who have those 600 f/4.0 and 400 f/2.8 lenses, these new lenses don't seem to be able to satisfy in the image quality department. Unfortunately, the wildlife images that capture my attention most are those with creamy backgrounds.
The 300mm f/2.8 seems to be the perfect balance for me.
For people like me, who salivate over those shots we see gotten by those of you who have those 600 f/4.0 and 400 f/2.8 lenses, these new lenses don't seem to be able to satisfy in the image quality department. Unfortunately, the wildlife images that capture my attention most are those with creamy backgrounds.
The 300mm f/2.8 seems to be the perfect balance for me.
Sep 25, 2026 at 07:49 AM
p.3 #20Sony 400/4.5 GM vs 400/2.8GM and 600/6.3 vs 600/4.0 comparison
Lt.Deadeye wrote:
It's probably a "me thing" but I believe it could be a bit different from the perspective of one who doesn't have an 'Excalibur' lens, just waiting in the cabinet, when it's needed to get THE shot. Then, I imagine having that Excalibur lens, one could more easily consider 'settling' for a lighter/ slower lens to add to the kit.
For people like me, who salivate over those shots we see gotten by those of you who have those 600 f/4.0 and 400 f/2.8 lenses, these new lenses don't seem to be able to satisfy in the image quality department. Unfortunately,...Show more →
Just my personal perspective after using the 200-600 6.3 for the last 7 years.
After getting enough experience in different conditions with it and getting a camera that does not limit me or its potential (A1). I've extremely rarely said after looking at a well-framed and focused photo that it could use better backgrounds. (I mostly shoot birds.). You'd need to have a distracting background very close to the subject for a 600 f4 to be able to fix and f6.3 be unable.
I share your desire for a much higher class of lens, but more for reasons of better light gathering for BIF at challenging light conditions and better autofocus motors for fast subjects.
It's probably a "me thing" but I believe it could be a bit different from the perspective of one who doesn't have an 'Excalibur' lens, just waiting in the cabinet, when it's needed to get THE shot. Then, I imagine having that Excalibur lens, one could more easily consider 'settling' for a lighter/ slower lens to add to the kit.
For people like me, who salivate over those shots we see gotten by those of you who have those 600 f/4.0 and 400 f/2.8 lenses, these new lenses don't seem to be able to satisfy in the image quality department. Unfortunately,...Show more →
Just my personal perspective after using the 200-600 6.3 for the last 7 years.
After getting enough experience in different conditions with it and getting a camera that does not limit me or its potential (A1). I've extremely rarely said after looking at a well-framed and focused photo that it could use better backgrounds. (I mostly shoot birds.). You'd need to have a distracting background very close to the subject for a 600 f4 to be able to fix and f6.3 be unable.
I share your desire for a much higher class of lens, but more for reasons of better light gathering for BIF at challenging light conditions and better autofocus motors for fast subjects.
Sep 25, 2026 at 02:22 PM