[seszett]

If you don't use a planar lens it will never really look good.

What I do for my part is just use an enlarger to which I attach my digital camera with various tubes and adapters to get the distances right, and an enlarger lens. These lenses are infinitely cheaper than "regular" planar lenses and they're just made exactly for the job, and the whole assembly is rigid and aligned so it's easy to get the whole negative right.