R5 with 100-500 + 1.4tc vs R7 with Canon 100-500

Steve Balcombe wrote:

drsnoopy wrote:

kristian1 wrote:

drsnoopy wrote:

Interesting comparison. On your second test, I still see a slight advantage to the R5.
However I have a question - what did you do to get the image scale identical? The R7 image should be 14% larger (800mm EFL vs 700mm FL). Did you zoom back to 437mm on the R7 to get 700mm EFL? In which case the different position of the zoom lens elements could affect the results. Or did you match the sizes by using different magnification on-screen in Lightroom? In which case apparent resolution is affected by interpolation (fractional magnifications show best screen resolution at 16.7, 25, 33.3,50, 66.7 and 75%, scales in between appear less sharp) - you would need about 87% on the R7 vs 100% on the R5.

Just interested to know what you did - not intended as a criticism, but to point out that there are confounding factors in such a test.

You forgot that r5 has higher mp count. It is 700mm at 45mp vs 800mm at 32mp.
Both images are at 300% of course , and lens is at 500mm in both cameras.

R5 image has slight higher magnification.

Kristian

Hi - naturally I know the R5 has a higher pixel count, as I own one, and the 100-500. However I do *not* see any difference in image size between the two images (R5 and R7 - both look identical) so if they are both had the lens set at “500mm”, you must have used a different image scale to make them appear the same size, as the R5 is at 700mm FL and the R7 at 800mm EFL, which is a 14% difference. They cannot both be at 300%, as there is a 38% difference between 32.5 and 45 MP. Please explain how you achieved the comparison at the same size on-screen - I’m genuinely interested, not trying to criticise!

The pixel density of the R7 is 38% higher (linear) than the R5, so if you were to shoot both at the same focal length the R7 image would appear 38% larger at 1:1. But by using the 1.4x TC on the R5, its image is made 40% larger (linear) so they appear very nearly the same at 1:1.

I think this is a better way to understand it than the MP count.

Thanks, that is a very good explanation of the (almost) identical image size.