Finalmente! Sigma 35 1.4 disponibile in pre-ordine

“ Ho guardato meglio il test di Diglloyd su un monitor migliore e ne viene fuori che dai due terzi dal centro fino ai bordi ed angoli lo Zeiss 35 1.4 ad f1.4 è molto più nitido del Sigma 35 1.4 ad f 1.4.
Ne consegue quindi una resa globale migliore dello Zeiss. „

“ The Zeiss 35/1.4 Distagon is easily outmatched here by the Sigma 35/1.4 Distagon on micro contrast at wider apertures, and color correction through f/8. If one wishes to shoot striking wide aperture images with very high contrast and sharpness and smooth background blur relatively free of distracting purple/green color blurs on neutral areas, then the Sigma 35/1.4 delivers the goods. „

“ 35/1.4 Distagon

The performance of the Zeiss 35/1.4 Distagon is limited by LOCA and SLOCA; the lens is otherwise very sharp and well corrected, but these color aberrations are strong enough to constitute a nuisance both when focusing and in the final image.

Context is appropriate: some very expensive Leica M f/1.4 and Leica S f/2.5 lenses suffer from similar effects.

At f/1.4 in particular, the 35/1.4 Distagon shows a veiling purple haze around high contrast areas that reduces the contrast of coarse and fine structures; this is LOCA which incurs a practical difficulty: it makes focusing ambiguous either via Live View or by eye. This violet fringing derives from the violet end of the spectrum and can (could) be addressed in part by lens coatings that attenuate deep violet; clearly the Zeiss 35/1.4 Distagon lens coatings do not do so (ditto for the Zeiss 100mm f/2 Makro-Planar, probably by intention of color rendition). The only surefire solution to LOCA and SLOCA is to stop down (in a loose sense, for "color depth of field"). In the case of the 35/1.4 Distagon the LOCA and SLOCA are strong enough that /4 is required to eliminate it, though very high contrast white-on-black lettering as seen with other subjects proves that it can linger even to ?/8 on out of focus areas (see the Top Left crop here also).

In addition to the violet fringing (haze), there is a pronounced foreground/background color split: an overall magenta foreground and green background centered around the ~14+ mark (and the reason that a gray card must be in focus to be worthwhile). This magenta/green color SLOCA and it too is addressed by stopping down, with f/2.8 delivering a razor thin area of black lettering on the white ruler, though of narrower "cleanliness" than desirable, apertures f/1.4 and f/2 remaining polluted by color cast and having no true black. In reality, it is not until ?/5.6 that the black lettering on the white ruler can be deemed true to reality (neutral). This reduces the contrast (MTF) of the lens under some lighting/color conditions, white/black being a challenging case.

The difficulty in focusing caused by LOCAL varies by the color of the light and by the color of the subject matter; bluish light or sunlight causes considerable difficulty due to the presence of deep violet light. For this test in 4600°K daylight, focusing in Live View mode on the doll's eye was a challenge due to the veiling violet haze caused by LOCA: it was deemed mandatory to focus at ?/2.8 to have confidence in the accuracy (knowing that there is little or no focus shift involved made this a viable solution). One partial solution would be to use an violet-cut filter as researched with the Leica 70mm f/2.5 Summarit-S ASPH, but that approach is only partly effective. A green filter for focusing might be best of all by cutting out the blue and red ends of the spectrum (not confirmed). But of course this is tedious and somewhat ridiculous except for methodical Live-View based photography. It is much more practical to stop down to f/2.8 for focusing (in Live View); doing so eliminates at least 75% of the LOCA haze along with bringing increased micro contrast with higher overall optical performance.

Wide open sharpness of the 35/1.4 Distagon is quite high, but at relatively low contrast due to LOCA and secondary LOCA. The 35/1.4 Distagon does not reach peak sharpness and color correction until the f/4 - f/5.6 range due to these color aberrations and this is a real shame given its otherwise highly appealing image rendition. True depth of field is also impaired; a larger and more diffuse blur spot is formed due to the differential color focus. However, that same property might tend to produce very appealing bokeh qualities, so there no clear-cut case for it being entirely negative in effect.

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Sigma 35/1.4 DG HSM

The Sigma 35/1.4 DG HSM shows a much lower level of LOCA and SLOCA, so much so that wide open the black lettering could almost be called neutral black (where it is in focus near "14"). The contrast of coarse and fine structures is high, due in good measure to being free of the violet fringing. The magenta color cast in the foreground in particular is impressively low. Whether the source of the excellent color correction is due to lens coatings or other factors or both cannot be determined here.

Nor is the Sigma 35/1.4 an laggard in the bokeh department: its high level of color correction contributes a pleasing neutrality that combine with the other pleasing blur qualities: a general avoidance of harsh edges or harsh transitions.

Stopping down to f/2, the Sigma 35/1.4 delivers impressive micro contrast, though not yet at peak levels. Also at f/2, the level of foreground/background SLOCA is reduced to an impressively low level. Many Leica M f/1. 4 lenses and even the M f/2 APO lenses would be hard pressed to perform as well at f/2 in terms of SLOCA.

By f/2, sharpness on the eye is quite high. Stopping down to f/2.8 - f/4, the results are nothing short of superb. Secondary LOCA at f/2.8 is minimal and effectively banished at f/4.

It's hard to find much to criticize at any aperture with the Sigma 35/1.4 DG HSM here. It is clearly an exceptional lens that can run with the best.
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“ In pratica ho dato via il 24-70L II per lo ZE 21 e il Sigma 35/1.4... „