Yes I have it. You are right though, I think I had the nifty fifty in mind, which is realy ugly in the corners. But the pancake got some pretty bad vignetting, heavy CA and also the sharpness isnt that nice.
View the image quality delivered by the Canon EF 40mm f/2.8 STM Lens using ISO 12233 Resolution Chart lab test results. Compare the image quality of this lens with other lenses.
www.the-digital-picture.com
Maybe my copy isnt the best, but anyway. When it comes to quality its pretty much my last choice
I do like it for travel though very very much. A new RF version is truely a good idea. I dont know why they didnt include it in lineup when the EOS R came out. That was somehow strange: they made a new, very compact FF camera, but offered pretty much nothing but SUPER heavy, highend lenses like the 28-70 f2 or 50mm f1,2... I think the pancakes are the obvious choise for a mirrorless camera... especialy when they presented the EOS RP - a SUPER tiny FF camera, but without any small lenses for it (besides the 35mm, which is stil not super small)