The Ultra-Fast Advantage; Case In Point: Leica’s Summilux-M 21mm f/1.4 & 24mm f/1.4 Lenses Page 2
A bigger aperture equates to a smaller depth of field. But at a given subject distance, a wider lens means more depth of field. If you want small depth of field with a wide angle, you therefore need something seriously fast, such as f/1.4.
As a general rule, we both prefer “deep field” shots with wide angles and even with standard lenses. Too many selective-focus shots seem to us to be gimmicky, with more emphasis on the rendering of the out-of-focus areas (the so-called bokeh) than on the subject itself. But this is not always the case, and if you want to try selective focus with ultra wides, these are a compelling choice.
The counterpoint to this is that if you are used to getting “deep field” shots as a matter of course with ultra wides, the Summiluxes can be too fast at full aperture: you get selective focus where you don’t want it. Of course you can stop down but we were caught on this a few times when we first started to use these lenses. It’s not so much selective focus as softness when you don’t expect it.
How marked is the selective focus? Well, a great deal depends on the size of your final print (bigger prints show less depth of field); on whether you are shooting digital or film (digital is enlarged more, for a given final print size, with a slight reduction in depth of field); and even on your subject matter. As a rule of thumb, though, we’d suggest 3-6 feet for the sharp focused point. As well as the pictures accompanying this article, there are dull but (we hope) useful comparison shots on www.rogerandfrances.com: go to Photo School, then Reviews.
The Technical Stuff
Since Joe Farace covers a good deal of tech background on the 24mm in his review in this issue we’ll concentrate on the 21mm. These two lenses were developed simultaneously, and are clearly variants on the same optical design: 10-glass, eight-group, with a moving (“floating”) group to optimize performance right across the focusing range down to 0.7 meters, 27.6 inches (dual feet/meter scale). The focusing movement is approximately 90?.
The design variations comprise changes to the curvature and thickness of the elements, and the use of two aspherical surfaces in the 21mm instead of just one in the 24mm. Click-stops are in half-stop equidistant rests down to f/16 in both cases. Smoothness of aperture and focusing rings is wonderful, as you would expect, but the focusing mounts on both lenses are somewhat firmer than the admittedly unusually light focusing on the last new Leica lens we bought, Frances’s 50mm f/2.5 Summarit.
The hoods deserve special mention for several reasons. First, they use Leica’s “positive stop” screw fitting on an external (male) thread: slower than a bayonet, but more solid and secure. Second, they do double duty as filter holders: Series VII (51mm diameter) for the 24mm, Series VIII (63mm diameter) for the 21mm. “Series” filters are in unthreaded, drop-in mounts: actually quite a tight fit, to stop them from falling out too easily when the hood is removed. Both hoods are of the “reentrant” type, with a reverse slope instead of flaring outward from the screw-on mount. As the filter sizes imply, they are similar in design but different in size, as are the rectangular slide-on caps—to which we prefer OP/TECH Hood Hats anyway.
Very importantly, the front glass of the 21mm protrudes ever so slightly beyond the rim of the lens—about 0.5mm or 1⁄50” by the look of it—so the hood should be regarded as an integral part of the lens, and never removed except for cleaning, to change filters, or to substitute the filter adapter (optional, for 82mm screw). There is a similar optional adapter (for 72mm) for the 24mm lens.
This protrusion is inexplicable unless you consider the hood as an integral part of the lens—which we do anyway. However, there may be some macho users who think they know better than Leica, and others who simply lose their hoods (dropped over a castle wall while changing filters, for example). This invites abrasion of the (very expensive, but mercifully replaceable) front element if they continue to use the lens. We’d be inclined to carry a spare 70mm domed lens cap against such an eventuality.
Performance is stunning: this goes without saying. Contrast and sharpness are unbelievable on both media: the only real limits are set by the film or the sensor, or (without a tripod) by the steadiness of your hand. Distortion has already been mentioned. Vignetting is marked at full aperture (especially on film), but by f/2.8, it is as low as for any lenses of the same focal length.
Some people dismiss modern lenses as “too clinical, too perfect” but we can’t help wondering how much they are influenced by price: older, less “perfect” lenses are a lot more affordable. Besides, it is not as if there are other, cheaper 21mm f/1.4 and 24mm f/1.4 lenses for rangefinder cameras. If you need (or want) the speed, that’s what it costs: end of story.
For more information, visit Leica Camera Inc. at: http://us.leica-camera.com.
For further information on the art and craft of photography from Roger Hicks and Frances Schultz, go to: www.rogerandfrances.com.