Leica 70mm f/2.5 Summarit-S ASPH
The Leica 70mm f/2.5 Summarit-S ASPH is the standard lens for the S2, equivalent to a 56mm lens on a full-frame 36X24mm DSLR.
The 70/2.5 is also the most compact lens of the line, and one wonders whether Leica might eventually offer a similar focal length at f/2 or faster, since f/2.5 doesn’t allow as much equivalent background blur as an 85mm f/1.2 lens on a 35mm DSLR.
As the MTF charts show, performance by f/5.6 is world-class. Real world images should have a snap and sparkle that few lenses can offer. Stopping down a little is definitely worthwhile.
Leica states that the 70/2.5 “gives priority to top imaging performance for all applications”. That’s a non-sequitor, but probably is meant to state that performance is exceptionally well corrected at all distances. Whether or not this also means zero distortion and/or very low vignetting remains to be seen.
I’ve seen complaints about the lens hood online. These complaints are misplaced, borderline cart-before-the-horse. The lens hood looks to be exceptionally effective at eliminating stray light: that’s it’s job! It reverses for storage just like Nikon and Canon hoods do, which suit me just fine.
The lens cap could be a little deeper, but otherwise works just fine. Only Nikon’s are better.
Nominal, per Leica.
The 1:4.7 close focusing allows very close shooting, approaching macro range; this is great for tight face shots (portraits).
|Specifications for Leica 70mm f/2.5 Summarit-S ASPH|
|Focal length||70mm (nominal), equivalent to 56mm in 35mm terms|
|Lens construction||8 elements in 8 groups with floating element and 1 aspherical surface, plus one “filter screen”|
|Focusing range:||1.6 feet = 50cm|
|Smallest object field:||1:4.7|
|Item Angle of view||42°, 35.5°, 24°|
|Diaphragm:||f/2.5 - f/22|
|Dimensions||90mm diameter X 93mm long
3.54 X 3.66 inches
|Weight||740g / 26.1 oz (890g / 31.4 oz for CS version)|
Wide open at f/2.5, performance is high over the entire frame, but there is definitely room for improvement.
The wave seen about 2/3 out at f/5.6 is almost certainly due to field curvature. Contrast for fine detail is the lower pair of lines, and to reach 80% at 40 line pairs per millimeter is absolutely outstanding even for a lens for a 35mm camera. This requires f/5.6 to achieve, but f/2.5 is already very good, especially for a lens covering a 45mm X 30mm sensor.
Mouse over to compare f/5.6.
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