"Scans" of my old slides

I have a box of the "best of" my old slides from when I was a teenager/early twenties. 1990s I think mostly.

I tried to scan them with my Ion Film 2 SD "scanner" which is really just a webcam and a light box but then I realised I could do a better job with the Canon PowerShot - using the Ion slide holder. Well "better" is subjective - the colours and sharpness are much better - but they are the wrong aspect ratio and quite heavily cropped.