All material ©2014 Kirk Tuck and presented exclusively at www.visualsciencelab.blogspot.dom If you are reading this on another site, without proper attribution it is not an authorized use of the material. If you are reading this on an unauthorized site DO NOT CLICK on any links in the body copy as it may infect your computer with serious viruses. Sorry to have to put this warning here but a recent search turned up dozens of similar infringements. Thanks for your authentic readership.
There's always something going on in downtown Austin. This past weekend one of those events was the "Gelato World Tour." I wouldn't have known about it but my swimming buddy, Emmett Fox, is the owner of several fine restaurants in Austin and was telling all of us about the Gelato Fest after workout on Saturday. They held it in Republic Square, which is usually a deserted block of land in the middle of downtown, next to the Federal Court building. I decided to drive down and check it out.
The weather was hot and sticky with bright sun. I took along a Panasonic GH3 body and three new lenses. I recently bought the three Sigma dn "art" lenses for the m4:3 cameras. They are also available for the Sony Nex cameras...
All three of the lenses have f2.8 maximum apertures and all three of them have a smooth, shiny metal focusing ring that gives the lenses a very minimal aesthetic. I like slower lenses for general shooting. It's my understanding that it's many times easier to design and manufacture a very, very high quality camera lens with a modest aperture than it is to even add one stop of speed. It all has to do with the precision required in shaping and polishing the glass elements. According to a Leica expert (Erwin Puts) it requires eight times more precision for every doubling of a glass element diameter. The faster the lens the harder it is to make the elements meet the design criteria.
While f1.4 seems sexier and can come in handy when you have to come back with an image a similar focal length lens with a 2.8 aperture can be designed to have higher performance across the frame. When it comes to zoom lenses and their necessary number of elements the difficulty of uniform precision is multiplied. In the last 15 years we've heard more and more often that modern zooms are now as good as prime lenses. And that may be very true if you insist that all your prime lenses have super fast maximum apertures. More effort goes into delivering speed than delivering uniform sharpness across a frame (not that uniform sharpness is always the most desirable metric in lens design).
There are obviously great fast lenses. But none are available at the prices at which you can buy the little Sigma Art lenses. I spent $239 on the 60mm lens, $199 on the 30mm lens and only $179 on the 19mm lens. The equivalent focal lengths when compared to full frame 35mm format lenses are, 38mm, 60mm and 120mm. Good focal lengths for my use.
The lenses don't have image stabilization so if you are an m4:3rds user and you feel the need for image stabilization you'll probably want to mate them with an Olympus body or, in the Panasonic camp, the GX-7. I'm shooting during the day with these lenses and in other circumstances I do not fear the tripod so I put them on whatever body I like and abandon all thought of anything more than good technique.
I know that the lenses have been reviewed all over the place. The consensus of reviewers is that the 19mm is pretty good. Not as good as the Panasonic 20mm but within a gnat's whisker. I'll go with that but I'll add that once you hit f4 you probably wouldn't see any difference at all between them and you'd be at the ultimate performance aperture for each product. With a GH3 in good light the focus is snappy and accurate. I used this lens with the wide area AF setting and used aperture preferred priority with the lowest ISO. It became a truly facile point and shoot camera system.
The 30mm is pretty widely acknowledged as very sharp in the center two thirds of the frame wide open and that's certainly my experience. In fact, I'd use it wide open all the time without ever worrying about the theoretical slight sharpness loss that more analytical reviewers mention. The 30mm is the smallest of the three lenses and, for me, the most useful for walk around art shooting and general social snapping. Long enough to get rid of unnecessary background but still wide enough for good framing of people around you.
The member of the family I am most interested in (and impressed with) is the 60mm. It's sharp. Wildly sharp. Turn-down-your-default-sharpness-setting sharp. Wide open and at least to f8. It's snappy, contrasty, sharp and bite-y. While I might have been happier with a 50mm focal length I'm still very happy to have the lens on my camera. Of the three, in my estimation this one is the "must have" of the trio. When I looked at the images on screen the ones from the 60mm, shot in the same manner as the other two lenses, looked distinctly over sharpened. If I were shooting with this in Jpeg I would turn down the sharpness control on a GH3 to minus 2. It's that sharp!
I snapped some images of the Gelato Fest but the whole even was small; four or five tents giving away samples to ticket holders, one tent dedicated to lectures and demonstrations about the making of gelato. After a quick circuit of downtown I headed home to do other stuff.
On the way back to my car I was walking down Sixth Street when I saw a man in a plaid shirt walking toward me. He had a black strap across his chest, kind Black Rapid camera strap style. But he had a metal pipe sticking up over one shoulder. Was it a tripod? We nodded to each other as we passed. Twenty feet later I turned to see what kind of photographic equipment he might be sporting. To my anxious surprise his "equipment" was an AR-15 assault rifle!!!! I didn't have a phone with me but as I looked up the sidewalk in the direction I was heading I saw a small group of construction people staring past me at the guy with the weapon. They were shaking their heads and their supervisor had already called the police emergency number to report the sighting.
Now, I believe in Texas it is actually legal to carry weapons in public but after all of the school shootings and workplace shootings I think a lot of people are understandably jittery about people packing powerful guns and heading toward a family oriented public event. The police were well represented at the event and I'm sure their dispatcher alerted them to the approach of the gun toter.
Thinking about it later I was convinced that it was one of the fringe folks who do stunts like this to make a statement about their right "to bear arms." I came to that conclusion because he didn't have multiple ammunition clips, body armor, or other weapons. His weapon was strapped to his back and not in a ready-to-use posture. He was casually dressed and in shorts. Not the profile you expect from an "active shooter" with premeditated intention. I'm sure the police who were on site would watch him carefully. But I'll tell you straight up, if I were at the event with my family or with small children and I saw a person walking through the crowd with an assault rifle we'd certain be heading to the car as fast as my feet could get us there....
I'm not virulently anti-gun and I don't want to get in a big political thing here about the right to own or carry weapons, but I think when you are walking through city streets with a military style weapon you are needlessly scaring the crap out of a lot of average people.
I've lived in Austin for over 40 years. It's the first time I've seen someone tote an assault rifle through the main streets of town. I hope it's the last.
A little situational awareness goes a long way...
But back to the lenses: I think Sigma has done a wonderful job supplying us with some interesting shooting tools. Be aware that they use a new magnetic focusing technology and when the lenses are not powered up they have a muffled rattle if you shake them or invert them. It's part of the design and not a defect. At least that's what I've been told.
You might like them.
Knowledge. A good differentiator!