R5+100-500+1.4x or R7+100-500?

I appreciate your posting the comparison, but I can't understand what point you think your comparison makes.

My understanding is that the question is, what is the picture quality if you stand in the same place with the subject at the same distance and you shoot with the R5+1.4x+500mm and the R7+500mm (no TC).

An R5 has 8192 pixels linearly (horz.) where an R7 has 6960) or a linear difference of ~1.36x more pixels per millimeter (8192 / (6960 x 1.6) = 1.359375). Thus with a 1.4x TC, the R5 should have slightly more pixels per millimeter on the sensor for the same size object.

So if you stood in the same place with a 500mm lens on and 1.4x TC on the R5, the image of the label should be slightly larger in terms of pixels at 100% than with the R7 and 500mm and no TC (at least if I didn't make an egregious math error above).

The mitigating factors would then be quality losses of the TC and the "pixel quality" differences between the R5 and R7 pixels.

RDM5546 wrote:

I just completed my third my third comparison shot session for collecting images from the label on the power pole near my house. I have made several small refinements in technique for each of the three test shooting days.

There is was a great deal of forum interest/attention to the use of the R5/ RF 100-500 with the 1.4X TC vs the R7 using the same RF 100-500 lens. These pictures are of a label that is over 100 feet from the shooter and all pictures are made from same shooting location.

Using the R7 and the RF 100-500 with no TC resulted in 6000 pixels on the label

R7 with RF 100-500 @ 500mm (note that is a shadow from a nearby wire block left side of image)

Using the R5 and the RF 100-500 with no TC resulted in 3000 pixels on the label

Using the R5 and the RF 100-500 with 1.4X TC and 1.96 more pixels on the label resulted in

R5 using as 700mm/f10 equivalent lens with the RF-100-500 and 1.4X TC

Using the R5 and the RF 100-500 using 451mm FL with 2X resulted in 6000 pixels on the label

R5 using as 904mm/f16 lens with the RF 100-500 and 2X TC

Note: the 902mm was the FL because the zoom got bumped changing the 1.4X TC with the 2X TC. Also note the increased number of pixels on the label from using the 2X TC rather than the 1.4X TC.

To judge the images above for detail you should adjust them to be side by side and same physical size on your large computer screen. The R7/RF100-500 without TC and R5/RD100-500 1.4X TC are best compared side side and adjust to make both the same size.

Despite being a f2X TC resulting in the aperture to be f13 at the 904mm the image it generations is pretty competitive with R7 image using only the bare RF 100-500