G Story

After a little more digging it looks like its an issue with Affinity and the lens profiles as pointed to in David in Ruslip's post. I tried to locate the lens profiles on my computer without any luck. Affinity claims that the profiles are uploaded with the application but even after deleting Affinity 2 and re-uploading the application I found no lens profiles. Either the profiles are included in the Affinity code and are not in a referenced folder and files, or it's pulling them off the internet (unlikely). Affinity provides no help with regard to the canned lens profiles. The Lensfun site only directs you to the Affinity web site. That being said, the EOS R5 correctly identifies the lens as a Canon EF-S 15-55 f3.5-5.6 IS. Selecting the Canon EF-S 15-55 f3.5-5.6 lens from the drop down instead of the IS eliminates the vignetting. This does essentially the same thing as changing the Crop Factor to 1.0 since that is the Lensfun Crop Factor for the Canon EF-S 15-55 f3.5-5.6 listing. I think this comes down to a Lensfun issue with the Canon EF-S lens profiles and Affinity's use of that profile.

I've Uploaded three copies of the same image, the CR3, JPEG, and the developed afphoto with "Remove Lens Vignette" deselected. You should be able to open the CR3 and reproduce the issue. If not, let me know.... IMG_0110.CR3 IMG_0110.afphoto

It doesn't appear to be a camera optical issue since the JPEG copy does not have a vignette and the key piece of data is that unchecking the "Remove Lens Vignette" actually removes the vignette. This points to an Affinity software logic issue.

This does not occur with all photos taken with this camera and lens. Currently it's set up to generate a CR3 and a JPEG. The JPEG does not show any vignetting. I use the Canon adapter for the EF-S lens and a quick review seems to indicate this only happens with wide focal lengths, greater than 25 mm. Post Crop Vignette is not set. I'm an electrical/software engineer and this has all the ear marks of logic error in the Affinity 2 code. I can bandaid the issue but where there is one bug, there are likely more.

It makes no sense to me that "Remove Lens Vignette" would in fact result in a vignette. It is definitely a bug in the application since most RAW photos have "Remove Lens Vignette" set and in fact there is no vignette. I'm going to take a guess that the application at least for the Canon EF-S 18-55mm lens flips logic on the Lens Vignette selection at lower focal lengths. This issue caused me several hours of research since the Affinity Help documentation mentions almost nothing about Lens Vignetting.