Filter to enhance the quality of image

[denzjos]

@Pixlab, Every lens has barrel distortion/color fringing (depends on the quality), that's why I recommend to take RAW photos (time consuming). Then the barrel distortion/color fringing can be corrected in the software (darktable, RawTherapee, etc...). Using a lens with a fixed focus (no zoom lens) greater than 100 mm is better. On the other hand, old photo prints mostly have barrel distortion/color fringing and in this case, it is about a flat object one is trying to digitise.