Optical corrections for Canon RF 24-240

[rsp]

Hi!
I think there is a new bug with this lens / EOS R in DPL4. At 24 mm, vignetting is corrected with the 1st “auto réglage DxO Standard” (sorry, I’m French, nobody’s perfect) and not corrected when using the 2nd “auto réglage : corrections optiques seules”, which is surprising as the “vignetting” box is blue in the two cases:

1st DXO Standard

2nd Optical corrections only

[rsp]

I’ve found the explanation: in the second case, the image is not cropped to eliminate the black corners as in “DxO Std”.
It should be enabled to avoid that.

[Pathal (Patrick)]

I think it should not be enabled as this is the correct behavior for this “corrections optiques seules” preset.

The issue of this lens is detailed in this other post

Canon RF 24-240

Yes, you have that right, MalcomC. The vignette is a well-known characteristic “feature” of this lens and it is supposed to be that way. Everyone who has reviewed it has pointed this out. As Dustin Abbot put it . . . " . . .what I saw was clearly a mechanical vignette – an obstruction that kept the corners of the frame from receiving light at all [as Perfrode correctly pointed out]. This was one of the compromises that Canon had to make to make this lens work. […] The lens actually frames w…

where it is explained that this black corner is not really due to vignetting but to mechanical restriction of this lens.

[rsp]

Thank you, I hadn’t seen the other post so I continued with mine.
Anyway we found the same solution.
This lens is surprising and though there is mechanical vignette it is still a 24 mm when corrected and cropped: I made various testing ans comparisons with my other 24 mm lenses (11-24 ; 16-35 ; 24 LII).