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(Application)
As an example, perhaps, the photo legend Henri Cartier-Bresson apply: He has almost always photographed with a 50mm-KB-fixed focal length. Ie equivalent to approximately 35mm in the (APS) Digital World. Then gabs for his camera no 60mm (equivalent to 40mm on APS), otherwise he would have perhaps preferred) While (we probably tend) hobbyists, like more weitwinkelig receive ("to look pretty much the motif into one photo" partially ruined), by striving for conventional postcard aesthetics in our minds, he was a a gifted Cutting selector, also and especially in scenes from everyday life. He had by the way hardly uses his 35mm wide angle. Thank God, because then he would not be what it is today.
I want my 40s trying to replace my 18-55mm kit in practice. In wide-angle and telephoto zoom I (Sigma 10-20; Pentax 55-300). In these border regions it also benefits from (who wants not afford there expensive FB), since one (without cropping will) has fewer opportunities and freedoms to change by relocating the shot (not even in wide angle; either one is already "with backs against the wall ", or in strong Wide usually pretty dominant foreground restricts location experiments of bildkompositorischen reasons too strong a). Cropping would indeed be necessary, "the solution", but requires a good photographic eye.
In typical motives for the intermediate focal length range, however, one often has motion degrees of freedom so that a push is actually not so important even without cropping will. This is especially true for street photography, for the 40mm thus is particularly suitable. Cartier-Bresson has, incidentally, never gecroppt despite essentially only a single fixed focal length! This is of course the very high school of photography (motif discovery and framing without Cropping and zooming). As far as I'm not ...
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(Detail contrast: very good)
The detail contrast is higher than in (m) a kit zoom at the same focal length (and visible, not just measurable). I liken this natural images with the 18-55 II kit, version 2008. detail contrast is not to be confused with the global image contrast (whom one might subsequently alterable in image processing). In bad detail contrast objects outshine their neighborhood. That would not comment by blurring, but by a kind of soft focus or haze effect, or as if on the lens a grease spot. But what really noticeable is when cheap digicams. For example, would the sky then Details fading as thin tree branches. To my knowledge, would that not be corrected by image processing because it is so neither is "Contrast" to "blur" in the sense of image processing programs.
But if the objective, as here, the '40s, is above average detail contrast strongly, of course, benefit not only the light / dark details, but also color-to-color details, these seem a little plastic emerged as the kit zoom.
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(Color fringing alias "chromatic aberration": practically not there)
I used to think that does not matter because you Just could neutralsieren using image editing any color plane displacements at the edges. Now I know from experience that it (with very sharp) lenses is good if it produces no chromatic aberration, because they have ceased trading artifacts in translating the sensor mosaic pattern in a full color image. In horizontal contrast edges (depending on converter, eg Bibble strong, Adobe barely) light / dark alternating rows of pixels (english "zippering" = zipper pattern), or at oblique contrast edges (eg branches) get this a 2x2 pixel blocks structure and stairs missed structure (also Adobe created this Artekfakt strong).
The reason is that every modern converter tries to extrapolate brightness information also from blue and red sensor pixels; when the red / blue image channels but offset from the green channel, converter programs are misled them and thank possibly with above artifacts.
So it is good and very useful for detailed cleanliness at the edges that the 40 Pancake produces virtually no chromatic aberration.
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(Curved focal plane: goes so)
This 40 is not suitable as a direct reproduction lens (as an objective for a flat subject in a short distance), because it at least in the vicinity of a slight curvature of the focal plane has (Curvature of Field). In any case stronger than my kit zoom. This means that it then at the edges slightly "short-sighted" (the focal plane lies in front of the image center). For Repro recordings to resolve the issue by either the aperture reduced to 8 or 11, or omitted pixel-peeping, or just buy a dedicated macro lens which is specifically optimized for short-range (at the expense of long range course) , This 40 is not a dedicated macro lens.
This is not to be understood as nagging but only as additional information. For non-Repro applications (ie outside) the lens is absolutely top.
By the way, a curvature of the focal plane rather than a lens (design) fault, but the most natural behavior of all collection lenses. The lens in her eye hath. However, Evolution has here against compensated by the "backplane" of the eyeball is not flat like a CCD sensor, but curved to compensate for this optical effect again. That is why we do not notice anything.
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(Hardly diffraction blur?)
I noticed in my tests, that the sharpness is still absolutely at stop 11 on the height, and begins to fall only very minimal until 16. I suspect that this diffraction blur typically begins a little earlier (my other zoom lenses).
Background: "diffraction" is the light-scattering at the edges (as just the edges of the aperture), and for very small aperture of the share DESS scattered light in the total light up higher (because the ratio of diaphragm edge to aperture area increases), so that the sharpness decreases rather again with very small aperture.
The 40s "Pancake" seems but to be very robust and tollerant. My suspicion is that it could be that the entire optical system (the iris) is due to the very short design closer to the sensor, so that the diffraction scatters on the shorter distance to the sensor according to less? If anyone knows more this (or similar experiences with short lenses has), please report as comment like - I would be interested;)
