A7RIII with sigma100400 vs A7III with sony100400

Hi all,

It's been a while again, hope everybody is ok :)
I have finally decided to swith from A mount to E mount and could use a little help deciding on the best way to go forward.
I use the A77II with sony 70-400 and mainly shoot animals in zoos and in the wild.

I always thought I would go for the A7III with the sony 100-400 and a teleconverter to get the same reach as I have now with the aps-c camera ( I am very used to using 600mm).
But I saw some videos about the 7III vs 7RIII and now I'm thinking maybe the 7RIII is a better choice and definatly a cheaper choice if the combo with the sigma 100-400 is a good option. I wouldn't have to buy a teleconverter, I could use to crop mode and still have 18 MP photos or will have lots of room to crop on the PC. I just can't seem to find any reviews on this combo.

I am hoping someone here has the A7RIII with sigma 100-400 and can tell me about it or someone who knows a good review about it. Any help will be much appreciated :)

thanks for your input. The A7RIV is out of my price range unfortunatly.
I don't think I will mind the weight of the 100-400, my current lens is heavier. I do wish that the 200-600 was a bit lighter though!

Imaginations wrote: ... I am hoping someone here has the A7RIII with sigma 100-400 and can tell me about it or someone who knows a good review about it. Any help will be much appreciated :)

I do have this combination. I haven't given it a lot of testing with wildlife (more bird shots), but it does seem to have a decent hit rate with its AF tools, and generates good images at the long end.

Its performance does jump in good lighting conditions. I think the small aperture at the long end does slow locking on to subjects a bit at the margin in poorer light.

It is quite manageable in size also.

C_N_RED_AGAIN wrote: the sony 100-400 is the best 100-400 period sharpness and focus acquisition speed surpass its rivals. save some more and get the riii ans sony lens

Every thing you say is absolutely true, but it's $2500 vs $950 for the Sigma, and when B&H had it for $850 about a month ago, there was simply no question, it was the Sigma. Sometimes you have to make the economic choice.

Imaginations wrote: Thx all for the input! Very much appreciated! I do agree that the sony 100-400 is the better lens, but what 2manycamera says, sometimes you have to make the economic choice and that's what I did. After many hours of thinking and calculating and seeing some more reviews on the camera overall, I bought the A7RIII :D

Indeed, you have to pay a lot extra for the benefits of the Sony 100-400.

I hope you enjoy the a7Riii. It was quite the change for me coming from an a77ii and a7R. It was the first E-mount camera that felt like a proper DSLR replacement to me. It's a very capable and versatile camera.

@Imaginations

I was similarly amazed with the first event I shot with it. The AF system nailed the focus with the Face/eye recognition every time. And it is capable of so much more.

It’s very customisable. I have assigned a lot of the still photography custom buttons to suit my (manual) landscape photography. And run a different customisation for video.

One thing that does puzzle me is the wheel has a preset for WB. And I almost never have to change that quickly during a shoot. I’ve assigned the ISO to the wheel over the WB. Because that’s something I don’t want to menu dive to change.

Compared to the first generation A7R it really does feel like a much better camera ergonomically as well.