Not sure if the R5 will be more frustration that it's worth.

I'll be using my EF L AF lenses used on my Canon 5D IV. If I purchase my first mirrorless the R5 I will get the necessary (fancier) $199 adapter ring. Maybe the drop in filter design thats a chunk of money $399
I like the specs 45 MP ect.
Not sure if the R5 settings will be more frustration that it's worth. Read some comments about video heat. Then comments about IBIS settings when using Canon EF lens with built-in stabilizing.
For the price I will probably skip this model and grow old waiting for the next super camera.
I will keep 5D IV wear out the shutter and have repaired it several times.

vision35 wrote in post #19377082
I'll be using my EF L AF lenses used on my Canon 5D IV. If I purchase my first mirrorless the R5 I will get the necessary (fancier) $199 adapter ring. Maybe the drop in filter design thats a chunk of money $399
I like the specs 45 MP ect.
Not sure if the R5 settings will be more frustration that it's worth. Read some comments about video heat. Then comments about IBIS settings when using Canon EF lens with built-in stabilizing.
For the price I will probably skip this model and grow old waiting for the next super camera.
I will keep 5D IV wear out the shutter and have repaired it several times.

The R5 is a terrific camera; but, certainly not something you have to justify staying away from to anyone I'm still keeping my 5D4 on hand, just to be sure I have a fantastic backup on hand.

That said, I would not bother with the more expensive adapters unless you absolutely need some of that functionality that you don't have covered in another manner on the dSLR. You will always have negative comments/experiences that some subset of users is going to focus on and complain about with every body and new system released. Dig in to those and find the details that matter to the type(s) of usage you are going to have for it; let *that* inform your decision more than just the 'headlines'.

A $55 meike adapter (standard) or $110 meike control ring is all that is needed to use EF/EFS lenses. I will warn you that the control ring adapter is less than useful when using long lenses, your support hand won’t be near that control ring to use it.

Also I don’t really see any questions asked, so my final comment will be, do what is best for you. However if you find you need more info to make a decision later, definitely ask.

Excellent point about the control ring and long lenses. Some of my shorter EF lenses are heavy enough that the ring may be difficult to easily use and enjoy.
My other questions are.
Can the photographer choose the Len's built-in or Camera body IBIS image stabilization separately?
Also if the Len's IS switch is turned off will the IBIS take over image stabilizing by itself ?
When lens built-in IS switch is On IS mode is not shown. Both the camera bodies IBIS and lens IS are working at the same time.
Someone online didn't like both image stabilizing systems operating once for some reason. I don't use DSLR cameras for video much so that may not affect or bother me.
I looked at the Canon R and the body size and diopter wheel being on the left side is yuck. I prefer using my left hand to hold the lens and right index finger for a diopter wheel.
The R5 looks like a great mirrorless camera and a serious upgrade.
The 5 DS on the other hand is half the price fits my budget better.
It does seem odd or slightly annoying to go backwards to get a little more 50.5 MP
The Elan II E eye control that auto focuses where the photographer is looking and more MP could make a future camera better.
Too bad customers cannot have a custom camera made.

Can the photographer choose the Len's built-in or Camera body IBIS image stabilization separately?
Also if the Len's IS switch is turned off will the IBIS take over image stabilizing by itself ?
When lens built-in IS switch is On IS mode is not shown. Both the camera bodies IBIS and lens IS are working at the same time.
Someone online didn't like both image stabilizing systems operating once for some reason. I don't use DSLR cameras for video much so that may not affect or bother me.

ANS: No, the IBIS is tied to the IS on/off switch of the lens, but if the lens has no IS, then you can toggle IBIS on or off. In my opinion, Canon should add a setting to tie IBIS to lens IS, or not, giving the user the ability to choose one, the other, both, or none.

I looked at the Canon R and the body size and diopter wheel being on the left side is yuck. I prefer using my left hand to hold the lens and right index finger for a diopter wheel.

ANS: How often are you changing the diopter for the viewfinder? I personally set it and forget it.

The R5 looks like a great mirrorless camera and a serious upgrade.
The 5 DS on the other hand is half the price fits my budget better.
It does seem odd or slightly annoying to go backwards to get a little more 50.5 MP

ANS: That missing 5Mpx is very trivial. It means you can print 6% larger with the 5DS than the R5, which is likely not even discernible to the human eye at any kind of reasonable viewing distance. That being said, the R5 will have more dynamic range, better ISO capabilities and will likely look just a bit cleaner perhaps.

The Elan II E eye control that auto focuses where the photographer is looking and more MP could make a future camera better.

ANS: That is on the R3, and remains to be seen on how many other models will have this.

Update.
I purchased the R5 locally and a $360 CarePAK 4YR directly from Canon.
Thanks for all the help everyone.
For a little extra money I think I may consider the R5 C when they are in stock locally.
I can usually get 24 months interest free financing and will pay $1500 on the first payment to lower the remaining payments to a somewhat budget friendly amount.
Meanwhile study the manuals for a few models. Thats a chunk of money for most camera bodies alone except the Canon R at $1500

You are not alone here, I have thread here about ditching mirrorless and keeping my eye on OVF.
I sold RP with lenses and EF-R heavy donut. Keeping 5D MKII and will update to IV once I need it.

If the Canon control ring adapter will change the aperture like the old FD lens design I might enjoy using it that way occasionally.