Tamron 18-300 (B061) on Sony A6400. I have applied the firmware version 2 for the lens. Hopefully that wasn’t a mistake.
Weirdish hardware problem where the lens vignette is not being removed. Specifically SOOC JPEG, which are supposed to have lens-correction applied in-camera. But it is affecting raw editing with darktable, too.
I posted a raw file here. Note that in my post, I took a screen shot from the SOOC JPEG. Notice the darker sky in the corners. The photo is f/7.1 at 50 mm. It is not so wide that the curvature of the earth and atmospheric affects are “real” (75 mm FF equiv.). Intermediate focal length and aperture should have no problem with vignette.
I am using darktable 4.8.1 to edit the raw. By default, the lens correction module is using “embedded metadata”. I switched it to “Lensfun” and the vignette correction is actually worse. This all looks worse when you add more contrast to the photo or darken the sky.
I see a post about Lensfun being updated for this lens. But I also understand that Lensfun is somewhat limited with zoom lenses - it’s only able to store corrections for one or two cases and corrections for other combinations are interpolated???
Manually trying to tweak the vignette correction in the lens correction module is hard … For this particular image, it is basically trying to remove a tone gradient from a solid color.
Concerning using embedded lens correction metadata:
they must be present (which already looks doubtful from your remark about SOOC jpegs)
darktable/lensfun must be able to read and use them.
For vignette correction, I tend to use the exposure module. Of course, that only allows a simple correction, but if you need more, chances are you get easily lost in the various parameters…
Oh, and according to these instructions for preparing lensfun calibration data, lensfun can use more than one or two points. The linked article suggests 25 pictures (data points) for its example, (or even 100 pictures if you follow the protocol for “professionals”). So it’s probably mostly the photographer’s patience that’s limiting .
Just updated my lensfun github clone, and the current data for this lens has 13 distortion entries evenly spanning the 18-300 focal length range. Yep, no vignetting data.
Downloaded the raw, opened with with my hack raw processor, and the lens correction tool readily identified the camera and lens for processing, so I’d say no problem with the metadata.
.