If you could have only one lens, what would it be? For me, that lens would be the Leica Summilux-M 24mm. It’s a wide-angle lens that isn’t too wide for most purposes. It’s extremely sharp across the frame with no red or cyan corner issues. When opened up to f/1.4, you can use it for most interior shots. Best of all, I like the versatility of the lens. You can use it for clean, almost clinical shots, where everything needs to be clear with a minimum of distortion. Or you can use it expressively to create moody images with pitch-dark blacks, evocative grays and shimmering highlights. The varying tones can depend on the light or your choices when processing the image. That you can shoot interiors or exteriors, deep focus or shallow focus, faithful reproductions or flights of imagination—all with the same lens—speaks volumes about its intelligent and meticulous design.

The 24 lux wouldn’t be the best choice for every M-series owner. At $6,495, it’s one of Leica’s most expensive lenses. It also needs an external viewfinder on an M9, though you can get by without one. The M9 has frame lines for a 28mm lens, but not for a 24mm lens. You can fudge this a bit, because there’s extra viewing area outside the 28mm frame lines, which roughly approximates a 24mm lens. If you wear glasses, you’ll have to move your head around to see that extra area. Even if you don’t wear glasses, you may have to strain to see the full area all at once. I bought Leica’s external 24mm viewfinder and have become quite used to moving my eye back-and-forth between the built-in viewfinder (for focusing) and the external viewfinder (for composition). For some, the back-and-forth will be a deal breaker for any M9-mounted lens below 28mm.

Fortunately, there are a few advantages to using an external viewfinder. The frame lines in the 24mm viewfinder are slightly brighter and significantly thicker than with the built-in viewfinder. In addition, the external viewfinder gives you a fair amount of viewing area outside the frame lines, which aids in setting up your composition. I may start using the Universal Wide-Angle Viewfinder (popularly referred to as the Frankenfinder) with the 24 lux. Though far more bulky than the 24mm finder, it allows for more accurate framing because you can use its five distance settings to manually adjust for parallax shift.

If you shoot the 24 lux wide open and close-up, you can produce out-of-focus areas with very nice bokeh, similar to what you might see with the 35mm lux. Alternatively, by stopping down and stepping back, you can have deep focus across the frame that’s consistently sharp with smooth gradations. The 24 lux weighs a hefty 500 grams (17.6 ounces). That’s almost as much as the M9 itself (at 585 grams). The 24 lux is also a relatively long lens physically, measuring a substantial 58.5mm without the hood or 75.6mm with the hood. It does block some of the image in both the built-in viewfinder and external 24mm viewfinder, though removing the hood will reduce the area that’s blocked. The partially blocked image is something I quickly adjusted to.

I like to think of a 24mm as a moderate wide-angle lens. Depending on how you use it, it can render your surroundings either as a wide-angle lens or a standard lens. When you shoot in portrait mode looking up at your subject, the altered perspective can add drama to an image. With the photo titled City Center Buildings, the interplay between the two buildings is intensified by the wide-angle perspective. The geometric patterns on the building to the right appear more abstract because they seem to be pulled away from the center. By contrast, the photo titled Bellagio Atrium shows less of the typical wide-angle perspective. It was shot straight on, as opposed to an oblique angle, so the wraparound effect is much less apparent.

My best photos with the 24 lux often fall between these two extremes. The photo titled Aria Lobby appears as though it might have been shot with a 35mm lens—if you look only at the left-to-right center portion of the image. As your eye wanders to the top and bottom of the image, however, the wide-angle perspective increases to the point where you’re not quite sure how much of the angular bending is due to the architecture versus the lens. The photo titled Dark Beast shows the same interplay with areas of varying  perspective. The beast’s head and tip-of-the-tail pull your eyes first to the center of the photo. As you move out from the center, the heightened angles (and dark processing) give the spiraling  stairs a more ominous feel.

I’m still amazed at how pliable the M9 files are when you apply different processing techniques. The photos titled City Center Skylights and Coit Tower show how well the 24 lux holds up to relatively straightforward processing, where the goal is clarity and evenness of tone. With the photo titled Cosmopolitan Hallway, I was able to process for deeper blacks without losing the subtlety of the lighter tones. And with the photo titled San Francisco Trees, I was able to push the contrast to an extreme without having the image fall completely apart.

For my two recent trips, I shot only with the 24 lux. It was a good experience that reminded me that, if necessary, I could get by with just an M9 and 24 lux. Of course, variety is the spice of life, and there are many fine M-mount lenses. But if you narrow the choice of lenses to those that are both fast and wide, you may find the 24 lux is the most capable of them all.

– David English

This is a guest post by David English, who 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.