What makes a great lens? Some photographers want an all-purpose lens with the widest possible zoom range. Others want the fastest lens possible for capturing photos in the dimmest of light. In the end, all that really matters is image quality. I had a chance recently to try out the new Leica Super-Elmar-M 21mm f/3.4 ASPH lens with my M9. I don’t want to leave you in suspense, so let me say up front, this is a great lens. The wide-angle 21mm focal length may not be a good fit for everyone, and it certainly isn’t the fastest lens available. Yet the images it produces are quite remarkable, as though it was recording a scene and extracting everything that makes the light most radiant. After just one afternoon, it’s now firmly in the running to become my favorite lens, despite my concerns that it wouldn’t be well suited for low-light interior use. Quite simply, it may be one of the very best lenses that Leica has ever produced.

My favorite lens has been the Summilux 24mm, while my second favorite lens has been the Super-Elmar 18mm. A 21mm lens would seem to be ideal for me, as it’s smack in the middle of my two favorite focal lengths. My concern with the Super-Elmar 21mm (or SEM 21) was the limitation that I’ve experienced with the maximum f/3.8 aperture on the SEM 18. With a maximum f/3.4 aperture, the SEM 21 would be more challenging to use indoors than my 24 lux. That concern hasn’t stopped me from using the SEM 18 to capture some stunning interior shots. I’ll often lower the shutter speed, rest the camera on a flat surface, raise the ISO a bit, or do all three things at once, if necessary.

When photographers talk about Leica lenses, they sometimes split into two camps. Some prefer the recent Leica lenses because they are more consistently sharp from edge-to-edge across the full range of aperture openings. Others prefer the older Leica lenses, which they claim have an indefinable dreamy quality (the famed “Leica glow”). This second group might refer to the recent lenses as too clinical, while the first group might look at the older lenses as not quite in the same league as the newer, more accurate versions. Keep in mind that both groups love their Leica lenses. They just have their preferences and favorites. And there’s a fair amount of agreement that some of the current lenses, including the 28mm Summicron and 50mm Summilux, are able to straddle both sets of qualities in a kind of rarified, almost mystical mix. I don’t quite agree with this old-versus-new split, in that I think the differences are overstated. I do agree that there are some lenses that are able to encompass all the extraordinary qualities that we associate with the full line of Leica lenses.

Which brings me back to the new SEM 21. I brought the lens with me on a visit to Old Salem in Winston-Salem, North Carolina. It seemed fitting to use a new lens made in Germany to photograph some of the original buildings from an 18th century settlement of Moravians, who came to the U.S. from Europe. It would be an interesting low-light challenge in that the buildings—for the most part—are illuminated only with the natural light from windows.

To see how well this lens can handle the subtlety of both direct and indirect light, look at the photo titled The Carpenter. Look at the wood shavings on the floor, the carpenter’s hair, and the mug on the windowsill. That’s the essence of how light gives shape to objects in real life. The photo titled Tailor’s Table shows how this lens can handle delicate colors. Look at the color of the wall as it shifts in hue from a slight yellow-greenish tint to a slight pinkish tint. That’s an accurate reproduction of the light as reflected from the various pieces of cloth next to the window. Because there was sufficient light, that particular photo was shot at the baseline ISO 160.

Because I shoot mostly with the 24 lux and SEM 18, it took a while to adjust to this smaller, more compact lens. Even with the screw-mounted lens hood attached, it is 55mm in length versus 75.6mm for the 24 lux (and 77mm for the 21 lux). Without the lens hood, the SEM 21 is a modest 43mm in length. Leica rates this lens as having a maximum distortion of only 1.5 percent. I don’t have the means or background to measure the distortion of a lens. What I do know, from looking at the images I shot that afternoon, is that the full frame sharpness and precision of detail were consistent across all the photos. There was also that indefinable something (the Leica glow?) that was present in many of the photos. Whether it’s due to inspired engineering or magic fairy dust, I’m convinced this lens will produce amazing images from photographers all over the world.

As a kind of postscript, I thought I should point out that with wide-angle lenses you’ll be able to shoot with slower shutter speeds than with standard or telephoto lenses. In other words, the maximum F/3.4 aperture on the SEM 21 may not be as restrictive for indoor handheld shots as you might think. If you’re used to shooting at 1/60 of a second with your 50mm lens, you should be comfortable with 1/30 of a second with a 21mm. As a result, you may not have to bump up the ISO (and increase the noise) in order to capture that once in a lifetime dimly lit shot. Why can you shoot a wide-angle lens with a slower shutter speed? Because of the wider view, any movement by the photographer will have less effect on the image, because the objects that could potentially blur are now smaller and will not shift as far within the frame. It’s good to know when shooting a slower, wide-angle lens that you can proportionally slow down the aperture speed and still achieve a steady shot. In that sense, the maximum f/3.4 aperture on the SEM 21 will function more like a f/2.4 setting on a 50mm lens.

-David English

David English has a day job as a technology writer. He has written articles for CNET, Film & Video, PC Magazine, Sky and other publications. David started shooting with a Leica camera in March 2009 using an M8.2 and moved to an M9 in November 2009. You can see his photos at www.protozoid.com. His main website is www.davidenglish.com, and his classic film blog is www.classicfilmpreview.com.