Canon R3

[Kayaker72]

That's not how resolution works.

This is actually very tricky. As you mention, in an ideal world where resolution can be scaled up without penalty, it is true. More resolution is always your friend. But in actuality, there are issues and penalties that are paid. So, I am going to talk a bit about those.

I think Kari was more suggesting that the additional resolution would not be of benefit in the circumstance he cited due to motion blur. Which it seems we all recognize and agree.

But, and you references this, just point out the potential issues of increase resolution in Kari's scenario, he'd also likely be fighting increased read noise issue in low light if he needed to use higher ISOs in low light.

Using the R5 and R6 as a comparison (nice, as same generation, very different resolutions):

Granted, at ISO 100 and ISO 400, they are about the same. But, as you increase ISO, the R6 has a little over 1 stop benefit in read noise over the R5. Moving more electrons = more noise

And this is not just Canon. This is comparing a few of Sony's cameras:

Even though the 7R II is older tech than the newer but higher MP 7R IV, it has lower read noise and the 12 MP A7S has much lower read noise.

And there are others, besides read noise. Before microlenses, there was the entire issue of losses to pixel sidewalls that increased with decreasing pixel size. Even post microlenses, which are not 100% efficient, there is still more difficultly in moving light to hit pixels as they get smaller and smaller. There is also the issue as some pixel sizes are starting to get into the size of light wavelengths (remember, "pixel size" as photographers calculate it is actual pixel + pixel sidewall) and red wavelengths start at 0.7 microns.

In a ideal world where noise is a non issue, and many forms of photography it's already a non issue, you want as much resolution as you can. There are times when it is rendered mute because of diffraction, lens softness or other factors. But it does't make it worse. It just doesn't take full advantage of it all the time.

This is why I almost didn't respond. But, hey, what fun would a discussion be then. Third world in is key...ideal. In an ideal world I agree. In the non-ideal world, I think we just need to be aware of and consider the issues that arise with increased resolution. You mention noise, diffraction, lens softness, but there are also motion blur, shutter shock, other camera vibrations, etc that all can impact that additional resolution. For example, on the R5, I am trying to shoot at 2x shutter speed to get consistently sharp images. But, after that, you have file size and all the issues with handling and storing that additional data including: data transfer is taxed, some components heat up, cards/memory fill up faster, and you have more computer lag when working with the photos. As I understand it, one reason "pros" might prefer lower resolution is the handling of the files: 20-24 MP gives them what they need and avoids all the other issues. I noticed going from my 5D3 to 5DIV and really noticed going to the R5. Matter of fact, I finally got the parts to replace my old computer which was often freezing up as LR imported the files from the R5. Never had an issue with the 5DIV.

And, then the question gets to be how much resolution do you need? My largest print is 16 x 24" which, at 150 to 300 ppi is 8.6 to 34.5 MPs.

There is probably a great Venn diagram that could be made here between pros and cons of additional resolution.

As for me, right now I am hoping that the R1 isn't a placeholder and also isn't a monster, but more MPs, say 35-40 MP if released in 2022 or maybe up to ~50 MP if released 2023-2024. But then there is a R5S released in the 80-120 MP range for those that really crave it. Amazingly, if you think of the throughput of the R5, 45 MP at 20 fps indicates that the Digic X could do 7.5 to 11 fps at those MPs. wow.