Thanks for sharing your real-world experience. As it happens, I had a 6D before I upgraded to the 5D4 and your post got me thinking - why not go back and look at similar images from both cameras and do some cropping to assess how much difference in image degradation there might be between the 6D and 5D4 when cropped by the same amount. Since the 6D is also 20MP (like the R6) perhaps that will give me an idea of what the R6 IQ might be like (though I'm guessing the 20MP sensor in the R6 is much better than the 20MP sensor in the older 6D?)

By the way, my main reasons for considering moving to an R6 (or "maybe" R5) are 1) for the IBIS and 2) what I understand is an amazing dual pixel AF system with eye/face tracking and 3) the incredible shutter speeds compared to the 5D4. I am VERY aware that technically the R5 would be a better camera overall (a good friend has one) and I could crop more aggressively, but truth be told, I don't often crop that aggressively, preferring instead to use a lens appropriate to the task. Would I love to have the R5? Of course but, being retired and on a fixed income, I'm having a hard time with the notion of plopping down nearly $4,000 for an R5 without any RF glass when I could get the R6 WITH a decent 24-105 f4 RF lens for $300 less than the R5 body alone. I also like the idea of having two identical card slots and not needing to invest in yet another card system (CF express), which adds additional expense.

I'm attaching four images, two of which were taken with the 20MP 6D (one full sized and one cropped the equivalent of 100% zoom). The other two images were taken with the 30MP 5D4. In both sets the ISO was 100 and the lens was a Canon 300m Prime shot at f4. Without cheating and looking at image dimensions, just from viewing the images, can you tell which set was taken with the 6D and which were with the 5D4?

Thanks for sharing your real-world experience. As it happens, I had a 6D before I upgraded to the 5D4 and your post got me thinking - why not go back and look at similar images from both cameras and do some cropping to assess how much difference in image degradation there might be between the 6D and 5D4 when cropped by the same amount. Since the 6D is also 20MP (like the R6) perhaps that will give me an idea of what the R6 IQ might be like (though I'm guessing the 20MP sensor in the R6 is much better than the 20MP sensor in the older 6D?)

By the way, my main reasons for considering moving to an R6 (or "maybe" R5) are 1) for the IBIS and 2) what I understand is an amazing dual pixel AF system with eye/face tracking and 3) the incredible shutter speeds compared to the 5D4. I am VERY aware that technically the R5 would be a better camera overall (a good friend has one) and I could crop more aggressively, but truth be told, I don't often crop that aggressively, preferring instead to use a lens appropriate to the task. Would I love to have the R5? Of course but, being retired and on a fixed income, I'm having a hard time with the notion of plopping down nearly $4,000 for an R5 without any RF glass when I could get the R6 WITH a decent 24-105 f4 RF lens for $300 less than the R5 body alone. I also like the idea of having two identical card slots and not needing to invest in yet another card system (CF express), which adds additional expense.

I'm attaching four images, two of which were taken with the 20MP 6D (one full sized and one cropped the equivalent of 100% zoom). The other two images were taken with the 30MP 5D4. In both sets the ISO was 100 and the lens was a Canon 300m Prime shot at f4. Without cheating and looking at image dimensions, just from viewing the images, can you tell which set was taken with the 6D and which were with the 5D4?

No I can't... I don't believe anyone can. Everyone needs to stop assuming you can't crop much with the R6. Most everyone here hasn't used the R6. I crop a lot with my camera and it doesn't bother me one bit.

You need to realize that with the IBIS, phenomenal auto focus with eye/facial tracking along with the premium RF lenses and the great ISO handling that your pictures are going to be much better and clearer than you have ever had. The keeper rate is also much much better. I guarantee that you will be very happy owning the R6.

I'm taking much better pictures than I ever have with this camera. The entire line of RF lenses are much better than the EF lenses. That's why they cost so much more. You really need to at least rent one and try it out for yourself.

Also if you need to pixel peep an image to see any differences then you are proving to yourself how good the R6 is. I'm not a professional photographer but I know if you had to take pictures professionally with the R6 that no one could tell the difference... Attached are three photos I took with my camera.

Thanks for your insight. Other than having bragging rights "mine's bigger than your's RE: resolution," I'm beginning to realize that the R6 is a heck of a lot of bang for the buck. I'm sure if I needed to do major cropping the R5 would be much better than the R6, but for most of what I would be shooting and the amount of cropping I would do, the R6 would be more than up to the task it seems. I'm not a pixel peeper, but I could see an advantage to the R5 if you really needed to crop aggressively. I'm not a big video shooter so the differences there are not even a consideration for me.

The emotional me would love to have the R5 just because it has 45 MP, but the practical me is saying that the R6 is a more logical choice given my shooting history. The money I would save, not just on the camera but also on the cost of CFe cards and the required reader, would go a long way toward getting some rally nice RF glass. Based on fact that you could not tell which of my images was shot with the 5DIV and which with the 6D (30MP vs 20MP) even though both images were cropped a good amount, suggests to me that 20MP is more than enough for 95% of what I would shoot. Thanks for sharing your images.

For the records, the picture of the Hawk was shot with the 5D Mark IV while the image of the sparrow on the feeder was shot with the 20MP 6D. Even when I zoom in on the sparrow's eye, the image looks more than acceptable IMHO.

I have made a decision. I think. Maybe. Probably. Going to keep the 5D Mark IV, which is a fabulous camera even if it isn't mirrorless. Then I'm going to see if I can save my pennies and get an R6 with at least one piece of RF glass (probably the 24-105 RF kit lens), then use an adaptor for all my other lenses on the R6. It would be sweet of they had a Flash Christmas sale on the R6 this year. That's how I bought the 5D4 when B&H had a 24 hour only sale for the 5D4, with a Canon battery grip and a 64GB SD card - all for under $2k. I'm not in any big hurry so I can wait to see if any grand sales come up for the Christmas season.

I have made a decision. I think. Maybe. Probably. Going to keep the 5D Mark IV, which is a fabulous camera even if it isn't mirrorless. Then I'm going to see if I can save my pennies and get an R6 with at least one piece of RF glass (probably the 24-105 RF kit lens), then use an adaptor for all my other lenses on the R6. It would be sweet of they had a Flash Christmas sale on the R6 this year. That's how I bought the 5D4 when B&H had a 24 hour only sale for the 5D4, with a Canon battery grip and a 64GB SD card - all for under $2k. I'm not in any big hurry so I can wait to see if any grand sales come up for the Christmas season.