8 out of 10 points and recommendedSharp image, great construction, cheap to buy nowadaysSlight vignetting on full frame at 17mm, hard to find now
I originally paid $500 new around 2006 when I first started learning DSLR with Canon 20D after getting recommendation by a pro with Tamron lens. All the way up to the time I had Canon 6D in 2014 this lens served me very well. It was only in 2014 the rubber grip started to peel off. The construction needless to say is amazing for what it feels a bit more plastic than other high end lens.reviewed February 4th, 2016 (purchased for $500)
I used this lens for astro, real estate and landscape mainly. Sure, the 35mm only shoots at f/4 but for what I did, it was the perfect lens. Stopping down did improve in overall sharpness although I never had an issue shooting wide open at 17mm either. If there was a problem having a body with AF microadjust should definitely help if anything.
This is probably one of the better ultra wide angle lens to get for any full frame these days even if it's used. I've seen new go for around $450 still but recently went back to Canon and purchased another for $250 so it was a steal.
If you're doing portraits and want shallow DoF of course I would get a better prime or zoom. Otherwise if you're stopping down for landscapes and other work like real estate, I recommend it. Sure, there's some distortion wider than 24mm but we're talking real estate. Nothing that can't be corrected in post.