RF135/1.8L IS vs. Sigma Art 135/1.8, Astrotest

There are already many tests of the new RF135/1.8L IS demonstrating its fantastic performance. For my own final decission to stay with my Sigma Art 135/1.8 or switch to the RF I did some additional night sky pics shown here. We all know the Sigma is fantastic. Can the RF be better in extreme corner definition and/or vignetting?  I pointed my EOS Ra (for the more critical CA and coma corner test) to the polar star field on a stable tracking mount and exposed 4 pics with same exposure for each lens with changing aperture (1.8/2.0/2.8/4.0) and compared them WITHOUT any lens profile correction (knowing that they work very well). See the results below. For me they are both fantastic performers with the RF having the edge for "colorless" corner sharpness wide open and the Sigma Art for Vignetting. Both trump everything that was available before in that focal range.

100% upper left corner UNCORRECTED: first horizontal row RF135/1.8L IS @ 1.8/2.0/2.8/4.0; second row Sigma Art 135/1.8 @ 1.8/2.0/2.8/4.0

Fullframe bright Urban night sky UNCORRECTED: first vertical row RF135/1.8L IS @ 1.8/2.0/2.8/4.0; second row Sigma Art 135/1.8 @ 1.8/2.0/2.8/4.0

Franz Kerschbaum wrote:

There are already many tests of the new RF135/1.8L IS demonstrating its fantastic performance. For my own final decission to stay with my Sigma Art 135/1.8 or switch to the RF I did some additional night sky pics shown here. We all know the Sigma is fantastic. Can the RF be better in extreme corner definition and/or vignetting? I pointed my EOS Ra (for the more critical CA and coma corner test) to the polar star field on a stable tracking mount and exposed 4 pics with same exposure for each lens with changing aperture (1.8/2.0/2.8/4.0) and compared them WITHOUT any lens profile correction (knowing that they work very well). See the results below. For me they are both fantastic performers with the RF having the edge for "colorless" corner sharpness wide open and the Sigma Art for Vignetting. Both trump everything that was available before in that focal range.

100% upper left corner UNCORRECTED: first horizontal row RF135/1.8L IS @ 1.8/2.0/2.8/4.0; second row Sigma Art 135/1.8 @ 1.8/2.0/2.8/4.0

Fullframe bright Urban night sky UNCORRECTED: first vertical row RF135/1.8L IS @ 1.8/2.0/2.8/4.0; second row Sigma Art 135/1.8 @ 1.8/2.0/2.8/4.0

Thank you for this test! The Sigma 135mm is my absolute favorite lens for portrait and landscapes. I was tempted to try out the RF135mm the other day at the store. Good thing I did not bring my camera With this test and other reviews, I think my conclusion is the RF135mm is too expensive for what I do, without any phenomenal gains in performance.

Thanks!  Yes the corners are very similar. Both of my lenses are well centred. And dont forgett the pics are done with an Ra! So (red)CA on an normal camera would be even less.

Very nice and helpful comparison. Thank you. Considering the tiny difference in the corner sharpness, much better vignetting, better build quality and MUCH better price, Sigma offers really unmatched bang for the buck.