Reply to How to find the megapixel usability of a lens.

Lens reviews are a good way to find the resolution of you optics,
in terms of so many lines per inch it can resolves.
Normally the L lenses do a good job.

A good lens requires a good sensor to work together,
the size and spacing of the pixels are important in capturing the
information delivered by the lens.

So the prices may indicate the quality of the gears.