Depends on what exactly you want to do with Canon EOS R6 Mark III. Photography or also video work?

For Canon EOS R6 Mark III I would definitely recommend Sigma 100-400mm f/5-6.3 DG DN OS. The autofocus performance is very fast The build quality feels premium and should last for years.

Canon RF 70-200mm f/2.8L IS USM is definitely the best choice for Canon EOS R6 Mark III. The image quality is excellent The fast autofocus makes everything feel responsive and accurate.

Why this lens? The image quality convinces in all tests - both for photography and for video. Unbeatable for the price, can only recommend. Have already done several projects with it, always satisfied. Also more than sufficient for demanding tasks.

My setup: Tamron 70-180mm f/2.8 Di III VXD for Canon EOS R6 Mark III - works great! The build quality is outstanding The controls are intuitive and easy to use.

My tip: Sigma 100-400mm f/5-6.3 DG DN OS for Canon EOS R6 Mark III. Very satisfied with it.

Better late than never, right? Honestly, if you dont want to spend a fortune or break your back, I've been really impressed with the Canon RF 100-400mm f/5.6-8 IS USM. Tbh, I was a bit skeptical about the f/8 at the long end, but the R6 Mark III handles high ISO so well it basically doesnt matter for most daytime stuff. I've been using it for birding and some local sports, and the autofocus is crazy fast. It’s definatly way lighter than the L-series glass, which is a huge plus when you're out all day (at least thats what worked for me). It feels a bit wierd at first because it's so light, almost like a toy, but the image quality is legit. It's probably the best bang-for-your-buck telephoto you can get for the RF system right now if you aren't doing professional wildlife work or shooting in pitch black.

Using Sigma 100-400mm f/5-6.3 DG DN OS for about a year for Canon EOS R6 Mark III and can only recommend it. The bokeh is beautiful The premium build provides excellent durability and weather resistance.

Totally agree with Jessica about the sensor performance on the R6 III. I have been shooting for years and honestly, the way these new bodies handle noise has completely changed my perspective on gear. I used to be such a snob about only using fast glass, but lately I find myself prioritizing weight way more than I used to. If you are gonna be hiking or just walking around all day, your back will thank you for keeping it light, and you really wont notice the difference in image quality for most shots anyway.

honestly im still pretty new to the r6 iii scene but i spent like way too many hours reading every single review and community thread i could find before picking my current setup—totally obsessed over the data. tbh im a bit of a nerd for the technical specs so i spent days comparing mtf charts and weight-to-reach ratios cuz i didnt want something that would kill my neck on a long hike lol. what i learned from all the forum deep-dives is that a lot of people prioritize the maximum aperture, but basically every review i saw mentioned that the newer sensors handle high iso so well that maybe the f-stop doesnt matter as much as it used to? i ended up going with a more lightweight one that everyone in the reviews seemed to love for its portability. its been a big learning curve trying to get the sharpness right at the long end—still trying to figure out if the specs i read actually translate to my real-world shots haha. do u guys think the technical data usually matches what ur seeing in ur photos?

Bump - same question here