Leica 21mm f/2 Super-APO-Summicron-SL: Introduction and Comments
Related: apochromatic, distortion, Leica, Leica 21mm f/2 Super-APO-Summicron-SL ASPH, Leica APO-Summicron, Leica APO-Summicron-SL, Leica Lenses, Leica SL lenses, Leica Summicron, Leica Summicron-SL, optics
Not sure when it ships, but I’d like to review it on the new Leica SL3.
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The about $5195 Leica 21mm f/2 Super-APO-Summicron-SL ASPH is a strongly wide angle lens.
- Full-Frame
- f/2 to f/22
- Dual Synchro Drive AF Motor
- Fast Ultra-Wide Prime
- 3 Aspherical Elements
Optical performance is ultra-high as per its MTF chart, mimicking its 28/2 sibling but with significantly less consistancy across the frame.
As with its 28/2 sibling the 21/2 most likely has strong distortion requiring distortion correction, which degrades sharpness significantly, unlike its 35/2 sibling which is a ~zero distortion lens. Since Leica hides the optical distortion from us (not included in datasheet, violating decades of precedent), it is hard to assess without field shots. This is surely not an accidental omission, a dog that is not barking.
Manufacturer’s description
As per Leica. See also the datasheet.
A world first
When the minds at Leica set their sights on innovation, they don't just aim to improve: they aim to set new milestones and create masterpieces of photography. That's exactly what they've done with the Leica Super-APO-Summicron-SL 21 f/2 ASPH. — the world's first APO lens with a 21mm focal length.
No compromises on performance
[DIGLLOYD: this appears to be FALSE in two senses: astigmatism is high (not unusual, could be correctable LaCA), and focus shift could rear its head, but mainly this: Leica does not disclose optical distortion in the datasheet, or anywhere, and the dog that is not barking is no mention of distortion anywhere. Which almost certainly means mandatory sharpness robbing software correction. A 21mm f/2 is considerably more challenging than a 28mm f/2 and distortion is high with the 28/2, which means distortion correction, which means substantial loss of micro contrast in areas stretched-apart by the correction].
This high-performance wide-angle lens captures images and videos with superior optical performance. Its broad viewing angle offers stunning perspectives and intricate detail. True to Leica's APO lens pedigree, it delivers exceptional contrast even when the lighting is less than ideal, opening up creative possibilities through exact control of focus and bokeh. Natural skin tones, smooth gradients, and corner-to-corner sharpness come standard with Leica APO-Lenses. They have everything a demanding photographer needs, whether you're shooting landscapes, interiors, architecture, or engaged in photojournalism and studio work.
[DIGLLOYD: isn’t it odd to not mention distortion, a major concern for landscape, architecture, interiors, etc, when all of these can have stricdt requirements for no low distortion?].
Construction in detail
With 14 carefully engineered lenses — three of them aspherical — arranged in 11 groups, this lens offers peak performance right from the widest aperture settings.
What sets it apart is its apochromatic correction, making it the world's first 21mm APO lens designed for full-frame cameras. To eliminate chromatic aberration, most of the lens elements are made of a special custom glass featuring anomalous partial dispersion, made possible by cutting-edge manufacturing techniques and sophisticated workmanship.
Sounds good. Am I’m sure it’s very very good. But the distortion rankles.
| Focal length: | 21mm |
| Optical design: | 14 elements in 11 groups |
| Entrance pupil position: | 22.9mm before bayonet |
| Working range: | 8.3 in = 21cm to INF |
| Largest reproduction ratio: | 0.19X = 1:5.3 covers 127 × 191 mm |
| Angular field, diag./horiz./vert | 91.7°/81.2°/59.5° |
| Filter thread: | 67mm |
| Weight (as actually weighed): | TBD |
| Weight, nominal: | 1.7 lb = 789 g |
| Dimensions (with caps): | 2.9 x 4 in =73 x 102 mm |
| Includes: | Front Lens Cap Rear Lens Cap Lens Bag Limited 2-Year Manufacturer Warranty |
