Leica's Summarit line of lenses, aimed at photographers who are willing to sacrifice some light-gathering capability in exchange for smaller optics at lower price points, received a full refresh at Photokina 2014. All of the lenses in the family, including the Summarit-M 35mm f/2.4 ASPH. ($2,250), are built to the same stringent mechanical standards as more expensive f/2 Summicron and f/1.4 Summilux lenses, and promise to capture images that are as sharp. Indeed, the 35mm Summarit behaves a lot like the Summicron-M 35mm f/2 ASPH.—its center is quite sharp, even wide open, but edge performance at wide apertures leaves something to be desired. If you're in the market for a compact, 35mm lens for an M-mount camera, it's tough to beat our Editors' Choice Zeiss C Biogon T* 2,8/35 ZM in terms of price and sharpness.

The 35mm Summarit-M is a small lens, measuring just 1.3 by 2 inches (HD) without the included hood. It's available in black or silver, with both color variations featuring anodized aluminum materials. The metal hood, which attaches via a thread on the outside of the barrel, adds about an inch to the height, but it's light enough that you won't feel the weight difference with it attached. A slip-on metal cap is included; it can cover the lens with or without the hood attached. The hood and cap designs are identical to those of the Summarit-M 50mm f/2.4 ASPH.. Like all new Leica lenses, the mount includes a 6-bit code that is read by the camera so images shot with it are automatically embedded in EXIF data—that's something you don't get with Zeiss and Voigtlander lenses.

All four of the lenses in the current Summarit series support 46mm lens filters, but first you'll need to unscrew the hood in order to install or remove a filter. This is a departure from some other Leica lenses, including the Summilux-M 50mm f/1.4 ASPH., that include an integrated collapsible hood for quick filter changes. How much this bothers you depends on how often you use filters; if you're shooting black-and-white film loaded in an M-A or with the digital M Monochrom, you'll likely want to use a color filter, which you'll need to remove when moving the lens to a color body like the M-P (Typ 240).

Like other M-mount lenses, the Summarit is purely manual focus. It locks on as close as 0.8-meter (2.6 feet), which is a little bit further than other rangefinder lenses—most other 35mm M-mount primes, including the Zeiss Biogon T* 2/35 ZM, focus to 0.7-meter. The short lens barrel can make gripping it directly for focus a chore, so you'll want to adjust it using the integrated finger grip (sometimes referred to as a tiger claw). Focus distance is marked on the barrel in meters and feet, and there's a depth of field scale marked at f/4, f/8, f/11, and f/16 so you can focus by scale or estimate depth of field at a given aperture. The physical aperture ring can be set from f/2.4 through f/16 in half-stop increments, and the 9-blade diaphragm maintains a circular shape when stopped down. The aperture ring is narrow, but features a ridged texture so it's easy enough to adjust by feel; it's practical to adjust it with just one finger.

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I used Imatest to see how sharp the Summarit-M 35mm lens is when paired with the 24-megapixel M (Typ 240). At f/2.4 it scores 1,815 lines per picture height on a standard center-weighted sharpness test, with the strongest performance in the center third of the frame (2,367 lines). Those results are higher than the 1,800 lines we like to see in an image. The middle third is a bit soft (1,591 lines), however, and the outer edges show some fuzziness at just 1,067 lines. Performance is a little better at f/2.8, with the center-weighted score improving to 1,956 lines based on a 2,587/1,699/1,074-line split across the frame. That's actually not too far off from what the Summicron-M 35mm manages at f/2—its center-weighted score at maximum aperture is about 1,907 lines, with edges that show 1,200 lines. But both the Zeiss C Biogon and the Leica Summicron-M 35mm are crisp from edge-to-edge at f/2.8, which isn't true of the Summarit.

At f/4 the lens improves rather dramatically in terms of resolution. Its center-weighed score jumps to 2,486 lines, with excellent performance through most of the frame, and just the outer edges trailing behind (1,345 lines). At f/5.6 the average score is 2,786 lines, with edges that approach 1,900 lines. Peak resolution hits at f/8—the Summarit shows 2,929 lines on average, with edge performance topping 2,400 lines. There's a slight dip in resolution at f/11 (2,810 lines) due to diffraction, and at f/16 the lens records 2,365 lines on average. As good as it is stopped down, the Summarit never hits the same level of crispness as the inexpensive Zeiss C Biogon—its resolution peaks at f/5.6, where it shows 3,764 lines.

The Summarit shows a little bit of barrel distortion, about 0.5 percent, but that's minimal enough to be a nonissue for the vast majority of photographers. More of an issue is chromatic aberration, which shows itself in the form of purple color fringing. It's a problem near the edges of the frame, and is particulary severe at f/2.4 when there's a great deal of contrast—typically when you're shooting a darker object against a bright sky. Narrowing the aperture mitigates this, and even in the worst example I could find in my test shots I was able to remove it with a +17 setting using Lightroom's Defringe tool. You can see a crop from the edge of the frame of an uncorrected (left) and corrected (right) image above.

The Leica Summarit-M 35mm f/2.4 ASPH. is the weakest performer of the four new Summarit lenses in terms of resolution, especially at the edges and corners, but it's still a solid option for your M-mount camera. If you're looking for tack sharpness from edge to edge at every aperture, you'd be much better served with the relatively inexpensive Zeiss C Biogon T* 2,8/35 ZM, which captures photos with absolutely clinical sharpness. When shot at wider apertures, the Summarit-M draws images with a very crisp center which gives way to subtle softness at the edges and corners of the frame, mimicking the look of the expensive 35mm Summicron ASPH. for about $1,000 less. And like the Summicron and the C Biogon, it's crisp from edge to edge when stopped down. You lose about half a stop of light gathering capability and a little bit of depth of field control when compared with the Summicron, but all things considered, that's not a terrible compromise to make. If you're going after the Summicron look on a budget, consider instead the Zeiss Biogon T* 2/28 ZM, which behaves much like the Leica 35mm f/2 for around $1,100, but is noticeably larger.