The Sigma 50mm 1.4 lens on my Sony Alpha 850.
I seem to be running about four years behind the times when it comes to buying lenses. Today I went to Precision Camera to buy the lens you see in the photograph, above. It's the Sigma 50mm 1.4 lens and it's received both rave reviews and mixed reviews since its launch in 2008. While I love 50mm lenses on full frame cameras the only 50mm I had for the Sony FF cameras was the Sony 50mm 1.4. Its big advantage is its size. It's probably half the size of the Sigma lens. It's also pretty darn sharp in the middle two thirds of the frame. But I kept hearing good things about the Sigma except from people who think that a high speed normal lens's biggest aspiration is to be sharp from corner to corner, wide open. That's just not going to happen for a reasonable amount of money. And while edge to edge sharpness is a good thing for people who like to photograph flat objects I've found that perfection sometimes gets in the way of art. We spend lots of time making images with ultra sharp lenses only to spend more time making the corners and edges soft so that by comparison our central areas seem even sharper.
By adding blur to the periphery of a frame with a person near the middle we also use focus to direct a viewer's attention to that which we want to emphasize. At one point, long ago, the people at Leica wrote something defending the idea of curvature of field and center sharpness in their fast 50mm lens. It made sense when I read it but I'm not going to drop into the rabbit hole of lens design versus shooting philosophy so you'll have to beat up someone else over that.
All mysticism aside there were two reasons I decided to buy this lens: 1. I've come to respect many of the offerings from Sigma over the last few years. To wit, the 70mm Macro, which may be the sharpest single focal length I've ever owned. And the 19 and 30mm lenses for the Nex are very good optics at very good price points. Even the 10-20mm wide angle zoom I bought last year performs beyond my initial expectations. It jumped nicely over the bar I'd set. 2. The other motivator was the drop in price engendered by a $100 rebate which has dropped the current price of this lens to $399. At that price it's hard to lose and it becomes almost a bargain.....if it delivers.
The 50mm 1.4 Sigma is a new optical design in a field of lenses that were mostly based on a Planar design from 60 or 70 years ago. It uses a molded aspheric element that supposedly goes a long way toward reducing chromatic aberrations and the rest of the design is supposed to have advantages in terms of reducing vignetting and increasing central sharpness.
I've only had the lens for short while but I've done some preliminary shots, both wide open and at f5.6 and I've been impressed so far. I'll spend some time with the lens tomorrow and hope to have some images to post on the blog.
Why the 50mm? Interesting question. I'll explain it with a story about an interview/conversation conducted by Ibarionex Perello with me and photographer, Seth Joel. Seth does corporate photography and his modus operandi is to use wide lenses like the 35mm 1.4 for Canon or Nikon, close in and nearly wide open. His photographs of people have lots and lots of background context. We were talking about different styles and when we turned to my work it was almost the reverse; very little background context and a much more isolated main subject. As we explored the subject further I admitted that I like the 50mm focal length but I love the 85mm focal length and, except for cliché uses, I just don't understand anything wider than the 50mm in any meaningful way. In fact, I'm heading to Denver on Weds. for a project about portrait lighting and the shortest lens I'm packing is the 85mm 1.5. I just don't feel really comfortable shooting wider unless I've already got cropping in mind.
If you love wide angles you do yourself a disservice following my example.....