Lightroom Classic introducing bad vignette

[3dMB]

I have just bought a Canon RF 10-20 f4 L Stm lens which I use on EOS R6 mk2. I have noticed that when I import the RAW images to lightroom, bad black vignette is added ot the image when lens corrections are disabled. I am not applying any processing presets for the import so everything is set to default. Default seems to apply lens correction these days, however when I turn off said lens correction this vignette is added. Looking at the RAW CR3 image, no such vignette is present.

Attached is screengrab of the RAW file and JPG export from Lightroom in default settings (minus lens correction).

I am running : 

Adobe Lightroom Classic

14.3.1 Release Camera Raw 17.3.1

Build [202505061331-b063faef]

[johnrellis]

"when I turn off said lens correction this vignette is added."

Reviews of the lens mention that without lens correction applied to raws, the barrel distortion and vignetting of raw images are significant:

https://opticallimits.com/canon/canon-rf/canon-rf-10-20mm-f-4-l-is-stm-review/#google_vignette 

The lens corrections provided by the lens profile correct for that. So why would you disable lens correction?

"Looking at the RAW CR3 image, no such vignette is present."

With what application and settings are you examining the raw image?

[3dMB]

Thank you for coming back to me on this.

I have viewed the CR3 file on MacOS Preview, Canon Digital Profession Pro 4 & Framebird online cr3 viewer - see attached screengrabs from the latter two.  Photoshop does as Lightroom does and clips the corners.

[johnrellis]

Mac Preview shows the JPEG embedded in the raw photo -- it doesn't know how to render the raw representation itself. As Richard explains, when cameras create raw files, they usually embed a JPEG rendered by the camera itself, and that usually involves applying in-camera lens corrections. As the review article I linked to above explains (as do other articles), the Canon cameras are most definitely applying lens corrections when they render the raw into JPEGs.

I never heard of Framebird before, but it's own description implies that it is also displaying the embedded JPEG preview: "Framebirds versatile viewer seamlessly handles CR3 files alongside other RAW formats, making it easy to view and organize your Canon photos. The viewer displays these high-quality images instantly, without requiring conversion or specialized software."  [Emphasis added]

Canon DPP is showing you its own rendering of the raw file, but it is almost certainly applying the lens corrections by default. (See the DPP manual for how to disable all lens corrections.)

Finally, if you upload a sample .cr3 taken with the lens, I can view it with the Rawdigger utility, which shows the raw pixels without any lens corrections. That will provide a third-party confirmation that what you're seeing in LR and PS is the raw file without lens corrections applied.

[richardplondon]

This is why we do not disable lens correction!

When you are "looking" at the Raw you are not seeing these dark corners which sit outside the intended image frame (nor are you seeing other aberrations). This is because the camera had at time of exposure immediately done a generic Raw conversion INCLUDING lens corrections. And saved that as the embedded preview within the CR3 file. And that preview is most likely IMO what you are judging this comparison by.