robertjerl Loc: Corona, California

You are familiar with Canon and the R5 is a superb camera.

As to lenses, well, the R5 (and other R bodies) can use the RF lenses plus all the EF mount lenses made by Canon or third party.
You have a choice of three adaptors, basic=$100, with RF control ring added $200 and with a filter slot added $400.

I got the basic for my R7 and my wife told me I should have gotten the one with the control ring as it makes EF lenses function like the newer RF mount lenses and she said she knows I will be buying more of the RF lenses; I now have 3=RF-s 18-150, RF 100-400 and RF 100-500L. She also says I will get another R body, probably a full frame to go with my R7 before the year is out.

She is pretty easy going on my cameras, lenses and books right now because I am trying to get her to pick a new
SUV for me to buy her, so she stops taking mine to shop and leaving her Honda Civic at the house. I don't even have a set of keys for it. I have to climb down into it and it then feels like I am wearing it instead of driving a car.

Architect1776 Loc: In my mind

Whatever you want.
I will stick with Canon.
It does have better AF from unbiased tests.
Color science is also better from numerous reviews.
ALL your current lenses work seamlessly with the R5 and work better.
The control ring adapter for your EF lenses make them even more versatile like the R lenses. Adapting them down to Sony their performance is not better and in cases degraded. That means with the R5 you only have to replace the body and not your entire system.
There are Hundreds of compatible lenses for the R5. Are you planning on buying Hundreds? Can you get an 800mm or a 600mm from any other maker for less and is as portable as the Canon offering?
Unless you are a lens collector, as a lot here are, Canon has you covered.
Sony would be starting over. Learning a new system and a far more infuriating menu system vs the R5.
Sony advantage is you can brag there are more lenses, for now but not long. Look at the Sony catalog and group all the same lenses and they are mostly all duplicates or triplicates. And if you are sold on 3rd party lenses go for it.
Finally the Sony salient feature is pixel peepers not real creators love it as they like pixel peeping and have never seen a photo standing back at the proper viewing distance. Which brings up the question is if Sony is so good IQ then why does it's photos seem to all need to be salvaged by a 1/2 dozen or so salvage programs as seen here on UHH?

Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

The good news is, you cannot make a mistake. All cameras today are good. It comes down to your personal preference based upon your likes and desires about ergonomics, ease of use for you, your owned lenses and your pocket book. I’ve made the switch from Nikon to Sony, then back to Nikon. My decision to go back to Nikon was not based on image quality, but familiarity of the brand and how it works. Muscle memory and intuitive menus make Nikon my brand. It’s different for everyone.

As far as the lens line up, I would bet that each of the brands has enough lenses to cover your needs and there are more coming out every day.

Once you make up your mind, don’t second guess your decision as you will end up with a great system.

Workflow and software is a huge part of the journey. Enjoy and take loads of photos!!!

Architect1776 Loc: In my mind

Architect1776 Loc: In my mind

PS, there are 30 RF/RFS lenses likely more than you will ever own unless you are a collector as many here are rather than creators.

w00dy4012 Loc: Thalia, East Virginia

Of course all the answers you get will be from people who have used both cameras extensively.

Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

IMHO, the more meaningful answers will come from those who have used the cameras extensively. Some may share opinions, but have not used the other cameras.

CHG_CANON Loc: the Windy City

The EOS R5 changed how we think about mirrorless cameras, how we think about photography, how we think about life. The others, not so much.

Architect1776 Loc: In my mind

Most people are not camera collectors with unlimited funds to buy every system.
Some of us though do rent various models.

CHG_CANON Loc: the Windy City

Check your logic. Canon has maintained 45+% of the global camera market for now 20+ years. Today, still bigger than both Sony and Nikon combined. Every EF (and EF-S) lens from day-1 in 1987 operates on all mirrorless EOS bodies, via the EF-RF adapter. Canon can't make native RF lenses fast enough to work without the adapter. It is Canon that has "more" lenses, both in unique designs and options in the used market as they build out their in-high-demand new mirrorless options. Sony FanBoyz make a lot of noise, and post a lot of image litter, but the market still speaks the truth.

Architect1776 Loc: In my mind

Actually it did.
And totally freaked out the competition forcing them to present the Z9 before fully ready and the A9.
And then the R5 compared very favorably to those cameras costing thousands more in cases.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

You are talking minor differences here. Both Canon and Sony make excellent mirrorless camera's. BUT, I caution you, if you like wildlife photography, if you buy a Canon, buy the Canon 100-500 mm lens, it is a great and very sharp lens.
If you buy a Sony, buy the Sony 200-600 mm lens. I shoot Sony at the moment, I shot the a9 and a1 with the 200-600 and 600 f4. The Sony 200-600 is the sharpest zoom lens I have ever owned. And I have see images from the Canon 100-500 that are also outstanding.
Below are a few grab images from my Sony 200-600 of Red Shouldered Hawks, you can get similar images from Canon lenses.
Please stay away from Tamron and Sigma lenses. PLEASE.
Good luck and keep on shooting until the end.

Architect1776 Loc: In my mind

Canisdirus

The skinny and unbiased report.

Sony: The GUMBY platform...everything fits it...it fits everything...deepest pool of native glass bar none.

Nikon: Slow to the game...almost disastrously...but has landed on its feet (must be run by cats).
It has a capable body lineup...but with much less native glass to choose from...but growing fast.

Canon: Got into mirrorless late but with true gusto...firing on all cylinders with their bodies. Glass is where Canon falters. Growing native glass...but is now restricting its customers from third party lenses. Punishing its customers...terrible sign.

Panasonic: Two formats...options...finally...finally developed phase detection AF...good glass selection...innovative.

Fuji: Videographers dream company along with Sony (edge goes to Fuji)...great glass...though the good stuff gets expensive.

Everyone else...not worth looking much beyond these companies...for now.

Architect1776 Loc: In my mind

Canon has 30 native lenses in the R system and more coming. More than 95% of people would ever buy and the full range of price options. Who has sub 1K 800m and 600mm that have phenomenal quality and portability from any other major maker including major 3rd party? It amazes me how many just read anti Canon posts and are clueless about the large number of R lenses, more than most people would ever get any way.