Im really satisfied with the Canon RF 135mm f/1.8L IS USM for outdoor sessions.

• 135mm: snappy AF, lighter weight
• Canon RF 85mm f/1.2L USM: amazing glass, way too heavy It works well tracking kids outdoors.

@Reply #2 - good point! Jumping in here, but I would suggest checking the technical specs before choosing. Be careful with the 135mm indoors or in tight Chicago spots.

• Canon RF 85mm f1.2L USM: Optically superior for the R5II sensor.
• Canon RF 135mm f1.8L IS USM: Better AF speed for kids, but requires way more space. The 260g weight difference might be less noticeable than the focal length limitations, honestly.

Building on the earlier suggestion, I totally agree that the 50mm is the sweet spot!! I was shooting a session near the lakefront last month and the wind was just brutal. I always worry about my gear in that Chicago grit but my Canon RF 50mm f1.2L USM handled the spray like a total champ. Its just so reliable when the weather turns nasty, which happens way too often here lol. Honestly, being able to move fast without my wrists aching makes such a huge difference when youre chasing kids for hours. Love it! Quick tip:

• Set your R5II AF to Case 2 to ignore obstacles so you dont lose focus when kids run behind trees.

This is exactly what I needed to hear. Youre a lifesaver honestly.

TL;DR: I feel your pain, the weight struggle is so real when you have a long day of shooting ahead of you. Saw this earlier but just now getting a chance to reply. Honestly, I have been dealing with the exact same issue for months. I spent years lugging around heavy glass and my wrists finally started telling me it was time for a change. It is such a balancing act between having that top-tier optics quality and actually being able to physically lift your camera after four hours in the field. I have been leaning towards just sticking with any prime from Canon lately since the ecosystem integration is so smooth, but yeah, the weight factor is always in the back of my mind. I am finally at a place where I just prioritize portability over that extra half-stop of light. You honestly cant go wrong with just picking up any decent prime from them if you want to keep your setup manageable. Definitely feels like the right move for my long-term sanity.

I've been thinking about your dilemma and i totally agree with the folks saying the 50mm is the sweet spot. in my experience, that 85mm 1.2 is a masterpiece but its just so front-heavy it throws off the balance of the R5II completely. over the years i've shot with the Sony FE 85mm f/1.4 GM and various Sigma 85mm f/1.4 DG DN Art lenses, and honestly, canon native glass handles chromatic aberration way better because of that BR lens element. the reason you pay the canon tax is the AF reliability. when you're chasing kids around, adapted glass or even some third-party stuff just wont keep up with the R5II's eye-tracking as well as the Canon RF 50mm f/1.2L USM. if you're worried about weather sealing in chicago, staying native is the only way to go. the 50mm is basically built like a tank without being a literal boat anchor like the 85. definitely worth the trade-off in focal length for the mobility you get... let me know if you need more info on the AF hit rates!

ngl i had the exact same dilemma when i moved to mirrorless. i actually rented the 85mm 1.2 for a week and while the images were stunning... my arm was basically dead by day three. for outdoor sessions where kids are running around like crazy you need something that doesnt make you feel like a weightlifter. i ended up going with the Canon RF 50mm f1.2L USM and honestly i havent looked back. it hits that sweet spot for me because:

• focus speed is lightning fast. those usm motors handle the r5 ii tracking perfectly so you wont miss those split-second smiles.
• weight is way more manageable. its about 250g lighter than the 85mm and better balanced so it dont feel as front-heavy.
• weather sealing is legit. i shoot a lot in light rain or dusty parks and never had an issue. the 50mm focal length is actually better for wiggly kids imo because you dont have to stand halfway across the park like you do with the 135mm. you can stay close enough to keep them engaged. it costs about 2200 bucks usually so it fits your budget perfectly. if youre worried about the bokeh... dont be. at f1.2 the backgrounds just melt away. it is a total workhorse lens that wont break your back during a long chicago shoot... definitely worth a rental to see if it clicks for you.

> I feel your pain, the weight struggle is so real Honestly, I totally get that. I tried to make the Canon RF 85mm f/1.2L USM work for months, but unfortunately, it just destroyed my shoulder during long sessions. It produces unreal images, but for chasing wiggly kids in Chicago, it is just not as good as expected for real-world mobility. If you want the weather sealing and speed without the workout, check out the Canon RF 50mm f/1.2L USM. It is way more balanced on the R5II body. Another pro tip: check out the lens comparison tool on The Digital Picture. It helped me visualize the weight difference vs the output before I made the switch. Saved me a ton of headache. If the 50mm is still too pricey, the Canon RF 85mm f/2 Macro IS STM is surprisingly sharp and barely weighs anything, though the AF is slower. Sometimes you gotta compromise a bit on the f-stop to save your wrists!