DSLR vignetting?

Hello, beginner here. I was scanning negatives with a V550 but am now trying out the Easy35. I have an Sony A7R5 with a Sigma 50mm f/2.8 DG Macro with a mount adapter. This lens released in 2004.

I’m getting very poor results compared to the scanner and from what I have read in these forums I believe it is due to the vignetting of my lens.
Images were shot at 1/200, F/5.6, ISO 100

Here is a flatbed scanned

Here is camera scanned

I tested this by detaching the camera from the Easy35 and manually pointing the camera at the edge of the mask

camera scanned

camera detached and pointed manually

Do I just need a better quality lens or is it something more trivial?

Here are full resolution images if this forum shrinks them down:

Found a video on flat-field correction, took an image without any film inserted and there is definitely vignetting:

took the sample image in lightroom and used it to correct the camera scanned image, and now it looks better than the flatbed scanner!

I feel like the flat-field correction feature in lightroom is half baked, the workflow isn’t easy and it keeps removing my raw files after it converts them to dng.

I got a Sony FE 50mm 2.8 Macro, native mount so no adapters, but I’m still getting almost the same amount of vignetting on the pictures. Even though lightroom applies the lens correction correctly, I have to slide the vignetting to the far left to get it to reduce. Even after that it’s still present. Could there be something else I am doing wrong?

I also played around with flat field correction and only got frustrated with the workflow.

What I did was to take a photo of just the light source like you did. Then within Lightroom I made a manual vignette correction to that photo and saved that as a preset. When I import my camera scans I apply that vignette correction preset before converting with NLP. Seems to work well.

Thanks! With over 9k negatives to scan I’ve ended up switching to grain2pixel because it’s a 1 click solution and it supports vignette correction.