Brochure

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Original technology minimizes
secondary spectrum
Exclusive low-dispersion glass
The degree to which light is refracted (bent) by glass
depends on the light’s wavelength (color). This fact
causes different colors of light to focus at slightly
different points. The result is chromatic aberration,
the color fringing that is particularly noticeable in
telephoto lenses. Most chromatic aberration can be
removed by combining a high-refractivity convex lens
element with a low-refractivity concave element. But
residual chromatic aberration known as “second-
ary spectrum” can only be corrected with selected
low-dispersion glass materials.
In addition to ELD (Extraordinary Low Dispersion)
glass and SLD (Special Low Dispersion) glass, SIGMA
uses FLD (“F” Low Dispersion) glass, which has the
highly desirable anomalous dispersion character-
istics of fluorite. Careful arrangement of these ex-
clusive low-dispersion glass elements gives SIGMA
lenses superlative image rendition untarnished by
residual chromatic aberration.
SLD, ELD or FLD glass element
Small secondary spectrum
Large secondary spectrum
Ordinary glass
Chromatic Aberration Correction
Effective correction of spherical aberration
and distortion
Aspherical lens
SIGMA’s aspherical lens technology contributes
to outstanding optical performance and compact
dimensions. These aspherical lens elements com-
pensate for the spherical aberration and distortion
which cannot be completely eliminated using con-
ventional spherical lens elements alone. They are
also key to reducing the size and weight of high-pow-
er zooms and other large lenses while improving im-
age quality. SIGMA has two kinds of aspherical lens
technologies. Hybrid aspherical lens elements are
made by forming a polymer in an aspherical shape
on a glass lens surface. Precision-molded glass
aspherical lens elements are made by direct forming
of the glass lens material.
Proprietary multi-layer coating technology
that virtually eliminates ghosting and flare
Super multi-layer coating
SIGMA’s own Super Multi-Layer Coating suppresses
flare and ghosting by preventing reflections with-
in the lens. All lenses in the current SIGMA range
feature this original technology. In digital cameras,
are and ghosting may also be caused by reections
between the image sensor and lens surfaces. Here
too, SIGMA’s Super Multi-Layer Coating is highly ef-
fective, assuring images of outstanding contrast.
SIGMA’s unique coating technology
Nano Porous Coating (NPC)
Incorporates porous silica as the coating material.
The porous silica layer has nano-sized holes with
air inside. Having holes of this size enables a large
reduction in the refractive index, allowing the reec-
tance to be lowered more than conventional anti-re-
ective coatings. As a result, reected light causing
flares and ghosting is sharply reduced, achieving
clear image quality.
A coating with excellent water and oil repellency
Water and Oil Repellent Coating
A water and oil repellent coating allows water to be
wiped away easily and prevents oils from sticking
to the surface. This makes for easier shooting in
challenging conditions and helps the photographer
maintain a clean lens surface.
Advanced focusing mechanism that reduces
lens movement and aberration variation
Floating system
This system adjusts the distance between lens
groups during focusing, thereby reducing the amount
of lens movement required. The result is less vari-
ation in aberration at different shooting distances.
The benets are particularly great in macro lenses,
since they cover a wide range of shooting distances,
as well as in wide-angle SLR camera lenses that em-
ploy asymmetric congurations of lens elements.
Focus systems for optimized performance
Inner and rear focus
In a conventional lens, focusing requires an exten-
sion of the entire lens or the front lens group. How-
ever, to better accommodate autofocusing mecha-
nisms and close up photography, a need has arisen
for lenses that do not change their length during
focusing or suffer from focus-dependent variation
in aberration. Therefore, SIGMA has developed fo-
cusing systems that only move elements within the
lens barrel. These incorporate smaller and lighter
moving lens elements, which help improve autofocus
speed. With their unchanging barrel length and small
variation in center of gravity, these lenses also offer
enhanced balance and stability. Furthermore, since
the front of the lens does not rotate, it is easy to use
polarizing lters.
Floating system
50mm F1.4 DG HSM
SIGMA LENS TECHNOLOGY
Our lenses are packed with advanced and unique technologies,
which we have developed over the decades as the lens expert.
30mm F1.4 DC HSM
Rear focus system
Inner focus system
35mm F1.2 DG DN