This is the article posted on the website. Maybe we can get a debate started on this. It has been a long time since there has been a good equipment debate on this site.

http://www.the-digital-picture.com/N...spx?News=17252

Sean, I have to say that I think that the pixel density theory is not an accurate assessment and I will explain.

I believe it is the FOV and the relation of the file size that makes camera shake more noticeable. Sure additional pixels make larger files, but it is the size of the picture that makes it noticeable. If you have 1/32 of movement that you see on a 5D III file it might be 1.5 to 2x that on the 5Ds R depending on the direction of the movement.

The increased pixel density of the 5Ds R makes the base file and picture larger. You know the group on here are pixel peepers.
When you zoom in to a 100 percent on a 5Ds R you are looking at it much closer than you would be on an equally framed 5D III or 5D II. Because of this your hand shake will be magnified as well. If you upszie the 5D III or 5D II file to the 5Ds R you would see an increase but the picture would pixelate. The 5Ds R magnify's your camera shake with the larger file.

So how can you get around the magnified camera shake. You can re size your picture smaller and it will not be as obvious.

While there may be a relation to pixel size and the way it shows camera shake, in actual field use I do not see that playing out.
The reason I believe this is the 5Ds R files are never worse than I see with other bodies I have used.
I have had the 5Ds R since August and have about 10,000 frames on it. What I am seeing in actual field use is that I am able to shoot at the same shutter speeds as my old 5D II. While I get camera shake that takes away from the file size they are never worse than the 5D II, and the additional resolution is there to take advantage of.

We see people in other forums saying that you have to have a faster shutter speed or tripod to use the high density 5Ds R. The truth I see is that you have to do those things with all of the DSLR bodies to take full advantage of their potential. The 5Ds R is not different in that respect if you want to maximize your equipment, but I can see the the resolution advantage in my pictures with just normal technique and as I said it is never worse than the 5D III.

If its true that you loose a stop due to shutter speed with the 5Ds R this camera is truly gimped because of its poor high ISO performance.
I am not sure why anyone would buy it. But I can tell you the statement I just made is totally false. If it were true I would trade it off in a second.