While there may be some notable exceptions that I am
unaware of, most older third-party MF wide-angles
are pretty bad (I had a Makinon 24mm f/2.8 (before
I knew any better) that was so bad the edges were
vignetted and the whole image was soft, noticable
even on a 3×5″ print; I got rid of it quickly).
Newer (last five years) thrid-party wide-angles
are the same design as their AF counterparts,
so for example, the Sigma 24mm (see my other post
on the topic) does better even than the Minolta
counterpart. Buying used, it can be hard to tell
the year of a design, and it can be pretty risky
getting a third-party wideangle. Remember, wide
angles are pretty hard to do well, especially
compared to 50mm or even 135mm. I have seen quite
a few very good 135mm third party lenses for minolta.
I have a minolta 28mm f/2.8 celtic that I got
cheap once. I was got it to give it away to someone,but
I was so happy with the results that I kept it,
and have been using it regularly ever since. I’ve
seen them for as low as $40, both on e-bay
and at places like cameta.com.
That is what I would suggest. KEH.com
is another of my favorite places to get lenses.