p.1 #1 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
I currently use my Sony A7RV for landscapes with GM primes, while for birding I use OM1-II + 50-200 2.8.
I'm considering trading in my OM camera and lenses for a sony A7RVI and 100-400 GM II - to simplify my gear into a 1-camera set. At 76. my mental slowing sometimes gives me difficults switching between two cameras with different buttons & set-ups.
My concern is the Sony setup would be too heavy for me to manage without camera shake. The difference in weight between the Sony and OM cameras is fairly negligible, but the difference in lens weight between 50-200 (a superb lens) and the 100-400 GM II is around 600 gm -- pretty substantial. I'll go to my local camera shop to try out the
One other issue: the OM-1 II seems to have better bird focus and IS than my A7RV. I tried using A7RV with 100-400 GM I and felt focusing was problematical, and the lens was softer than I expected (maybe a bad copy?).
Does the A7RVI close the gap or surpass the OM in bird focus and IS? Of course the resolution of the A7RVI is tempting....
p.1 #3 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
good point, thanks
Jun 16, 2026 at 02:02 PM
Steve Spencer Online • • • • • • • Upload & Sell: On
p.1 #4 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
sierrabob wrote:
good point, thanks
I think it is better to compare the Sony 100-400 f/4.5-5.6 GM with the Olympus OM 50-200 f/2.8, they are closer in capabilities and weight. Making that change might make a lot more sense.
p.1 #5 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
Steve Spencer wrote:
I think it is better to compare the Sony 100-400 f/4.5-5.6 GM with the Olympus OM 50-200 f/2.8, they are closer in capabilities and weight. Making that change might make a lot more sense.
I agree that makes more sense in comparing the optical capabilities, but the original GM is showing its age in the AF department. I've never used the OM kit, but the OP's report of a less satisfying experience with the GM doesn't surprise me. I had one I was using in a kit with the 70-200GII for wildlife, and then I replaced the GM zoom with the 300GM. Both lenses are significantly more sure-footed trackers than the 100-400. After we got burgled, I replaced the GII and 300GM, but didn't bother with the 100-400.
p.1 #6 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
I just looked at the length of the 100-400 GM II. It looks very awkward to carry around - makes me lean to keeping my current setup.
The big advantage of OM system is, being M43, lenses are generally smaller even when not all that much lighter. I prefer the Sony colors, and of course the resolution but...no free lunch in physics.
Jun 16, 2026 at 04:29 PM
Steve Spencer Online • • • • • • • Upload & Sell: On
p.1 #7 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
freaklikeme wrote:
I agree that makes more sense in comparing the optical capabilities, but the original GM is showing its age in the AF department. I've never used the OM kit, but the OP's report of a less satisfying experience with the GM doesn't surprise me. I had one I was using in a kit with the 70-200GII for wildlife, and then I replaced the GM zoom with the 300GM. Both lenses are significantly more sure-footed trackers than the 100-400. After we got burgled, I replaced the GII and 300GM, but didn't bother with the 100-400.
Having owned the A7r V, however, I wonder if the OP problems were the 100-400 f/4.5-5.6 GM or the camera. I know that for challenging wildlife I always thought the A7r V was a bit limited both in fps and in AF. I suspect he might have a lot more success with the new A7r VI. No doubt the 300 GM would be a lot better and if he can afford it, then I would concur that would likely be a much better way to go, but that lens is 4 to 5 times more expensive.
p.1 #8 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
Steve Spencer wrote:
Having owned the A7r V, however, I wonder if the OP problems were the 100-400 f/4.5-5.6 GM or the camera. I know that for challenging wildlife I always thought the A7r V was a bit limited both in fps and in AF. I suspect he might have a lot more success with the new A7r VI. No doubt the 300 GM would be a lot better and if he can afford it, then I would concur that would likely be a much better way to go, but that lens is 4 to 5 times more expensive.
It's possible. I did only use the lens on the rV. However, the GII and 300GM were both better trackers on it, too.
Also, I'm not recommending the 300GM. But the new 100-400/4.5 does keep up with it from an AF perspective.
p.1 #9 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
freaklikeme wrote:
I agree that makes more sense in comparing the optical capabilities, but the original GM is showing its age in the AF department. I've never used the OM kit, but the OP's report of a less satisfying experience with the GM doesn't surprise me. I had one I was using in a kit with the 70-200GII for wildlife, and then I replaced the GM zoom with the 300GM. Both lenses are significantly more sure-footed trackers than the 100-400. After we got burgled, I replaced the GII and 300GM, but didn't bother with the 100-400.
The old 100-400 has nearly flawless autofocus and tracking - even with the smallest fastest subjects. I would still pick this lens over any other lens if I wanted to be sure of capturing fast action. The zoom ring on the new version might be a small improvement but the extra weight is not and the faster racking speed on the 300gm often leads to focus jumps to the background during acquisition and doesn't show any meaningful improvement to the hit rate during a sequence.
Its hard to see how you can improve on the hit rate of the 100-400. f/2.8 is useful in very low light but if you have to use f/2.8 for light then BIF images will probably be a bit average anyway.
The first time I have felt the 300 f/2.8 may have an edge is when shooting the A7R6 in APS-C mode where the extra light might mean that APS-C mode isn't constrained by available light from slower lenses.
p.1 #11 · Birding A7RVI + 100-400 GM II vs OM1-II + 50-200 2.8
Troube with the OM, it's 20MP all the time even when you fill the frame. If the OM were a 32-40MP APS-C sensor then I'd have been all over it with if they made say a 400 f/4 Pro or the 150-400 was a decent price.
