the sigma 20mm/1.8: a quick review

21 Apr 2009

So, a friend of mine was selling his Sigma 20mm f/1.8 lens, and after a quick bit of research, I decided I wanted it. My default carry lens for low-light portraiture (read: bars and concerts) is my canon 50/1.4. It’s my baby. Sharp as a tack, fast as hell, quick AF, etc – basically everything you’d want for low-light situations – and the 50mm on a 1.6x crop sensor is good for portraits.

But. Sometimes, you know, you want something wider – and there aren’t a lot of fast wide/super-wide primes. But there is this one. So I bought it.

First, the good: … it is 20mm. and it is f/1.8 which is nice and fast. That’s … about it, I guess.

The bad: It’s huge, and it’s heavy even for its size. The AF motor is basically the slowest I’ve ever seen on a lens, in addition to being noisy as hell. The glass is subpar, as well. It is … not a sharp lens, especially wide-open at f/1.8, which is sorta where I had planned on usually using it. Not being sharp also impacts the ability of the AF to function properly, so in addition to not being sharp, you get a lot of missed AF acquisition, resulting in the slow, noisy AF motor chugging its way back and forth desperately hunting for focus that it can’t find.

Bottom line: a 20mm f/1.8 prime would be a great addition to my lens collection – unfortunately Sigma’s offering kinda blows. Rather: you get what you pay for – that’s what I should say. If you’re in the market for a decent wide-angle lens for landscapes or something, it’s probably a good option for that. But I already have my EF-S 10-22 for that. I wanted something wide and yet fast. This doesn’t cut it for that.

So, I think I am going to sell this. I am not sure what, if anything, I’d replace it with, though. The canon 14/2.8L is pretty sweet, but even that’s pretty slow for low-light stuff. Plus, I haven’t won the lottery. Yet.

UPDATE: So, so many people hit this page searching for this lens I feel should amend it. I haven’t sold this lens, and I’ve learned to like it a bit more. It still has all the defects as listed above, but that’s life. It also provided a convenient replacement for the EF-S 10-22 when I moved recently to a 5D.

UPDATE TO THE UPDATE: So, uh. I’ve actually found a better replacement to the Canon EF-S 10-22 in the Sigma 12-24. And yet, I’ve still kept the Sigma 20/1.8. It’s just nice to have a wide, fast option in my lens bag now and then. So there’s that.