Converting Used Canon FD lenses for E420

Well, the Canon mount has a shorter flange to sensor distance than 4/3, so in that case you can't get an adapter to mount that lens that will allow focus to infinity. (Canon lenses can focus properly on m43 cameras du to the shorter registration distance)  Suppose you could remove the mount and cobble on an OM mount, but you'd likely wind up w a non-working lens.

Nikon lenses don't have this issue.

However, if you are looking for a wide lens, you are more or less stuck w the offerings in 4/3 mount, since there is little legacy glass available wider than 24mm, and while 24 is wide on a 35mm camera, it's only 'normal' on 4/3

So, you can choose the Sigma 10-20mm. the Zuiko 9-18, 11-22 or 7-14, or a 8mm FE

Best bet for low cost, good quality wide would be a used 9-18mm, although an 11-22 is not that much more and a step up in build. the Sigma is discontinued and would be hard to find, the 7-14 is top of the line wide for 4/3.

then again, if 12mm is wide enough for you, it might be worth the $$ for the 12-60 which is an excellent all around lens, although if you're shooting architecture there's a slight distortion at 12mm which is not usually evident for landscapes.

--
Art P
"I am a creature of contrast,
of light and shadow.
I live where the two play together,
I thrive on the conflict"