Levina de Ruijter wrote in post #19410538
I would advice your final alternative and that is to do nothing until the camera arrives and just use it with your older lenses. The results might surprise you. So wait a bit before you start replacing your current lenses.
One thing I am wondering about is the Diffraction Limited Aperture (DLA) of the R7. It is only f/5.2. On the R6 it is double that at f/10.6. I had no idea about this but stumbled upon this information just a few days ago on the TDP site, in the R7 review. So I now wonder if that is causing or contributing to the softness I saw in birds a bit farther away, for which I obviously used the RF 100-500mm @500mm which means shooting at f/7.1. So with the R7 having a DLA of f/5.2, diffraction surely has a softening effect when shooting at f/7.1. Maybe the tech guys can say something about that.
If you look at the pixel level, you will see the same diffraction blur with double the f-number on the R6, but if you normalize to sensor area, the blur will be twice as large for the R6 with double the f-number. If you halve the f-number with the R6 to be the same as the R7, then the diffraction blur is the same normalized to sensor area, but the pixelation blockiness and AA filter blur are twice as large with the R6.
The concept of DLA is mathematically correct and consistent, but that does not mean that it is directly meaningful in any given situation, when taken at face value. It completely ignores how many pixels the subject or composition is composed of. Pixel-level metrics are meaningless until you take the number of pixels into account. Also, there is no hard limit occurring at those ratios of pixel size to f-number; it is just an arbitrary point chosen by someone, influenced by their philosophy, in a long tail of trade-offs.
What really matters when all is said and done, is how large the diffraction blur is relative to the image size or subject size, including any cropping. Higher pixel densities do not make the blur larger, with the same subject, distance, f-number, and focal length.
When you were shooting those birds like that kestrel in the field, the blur from the air and any mis-focus that the air would have caused were clearly the greatest blurs, and that is what made it impossible for the R7 to get any significant detail benefit in that situation.
When multiple blurs are combined, the blurs that are smaller have even less influence than their blur size would suggest. Blur adds "in quadrature" so if you had one blur of 4 pixels radius and one blur of 1 pixel radius, they do not combine to become 5 pixels; they combine as the square root of the sum of the blurs squared which is the square root of 16 + 1 (17) = 4.123 pixels. IOW, the 4x smaller blur did not increase the total blur size by 25%; it only increased by 3.1%. So, diffraction is only a big part of total blur when there are no other much larger blurs.
