Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Super bargain--for a full frame camera

I got one of these second hand for my Canon 5D. I wanted to get a wide angle lens, but couldn't afford 700 dollars or more. I wasn't expecting much from this lens, and got a really pleasant surprise. It is surprisingly sharp and does a really good job. I generally keep it stopped down to 5.6 or 7.3, but I have good edges and even corners after I do so. This probably isn't the best wide angle you can buy, but for the money it is a heck of a bargain.