I while back, I managed to score a Canon EF 50mm f/1.4 USM lens on ShopGoodwill.com. As always, a Goodwill auction purchase is "as is." Turned out that both automatic and manual focus on the lens would not go below four meters. There has apparently been a long-standing problem of this sort with that lens. It has a part with a design flaw that makes it very easy to damage. A repair company was able to replace the flawed part with a redesigned one that isn't as easy to damage. It wasn't a cheap repair, but it's not a cheap lens, either. Of course, the lens also got a thorough cleaning as part of the repair.
Although I already own a couple of 50mm f/1.4 lenses, they are both vintage, manual focus lenses. Perhaps because of that, I hadn't been as attuned to their superior light gathering properties. Since this new one is made to work on a Canon digital SLR, I can more easily appreciate the superior optics. Foremost is that the lens can work really well in low light and natural situations.
Another great feature of the 50 is the focal range. It's great for portraiture because it give a nice blur to the background.
Here's one of the best shots I've taken with this newly repaired lens:
This is a great spangled fritillary butterfly on an iron weed. I shot it with the lens wide open at f/1.4, where it is said to be "soft." Note the dreamy background, which is the woods behind the flower. If I want sharper pictures, I'll need to stop it down to at least f/2.0.
Despite this newer, easy-to-use lens, I'm going to find it difficult to part with my Konica 50mm manual lens. I'd love to compare the image quality side-by-side with these two lenses. Perhaps another day.