SIGMA wr-ceramic protection 77mm filter
Good filter. Glass good, glass clean
Comes as pictured
If any problem, I offer 30 days return for full refund.
Filter info:
Sigma WR Ceramic Protector (available from 67mm to 105mm)
Interchangeable lenses are the most important element of photographic
expression, and to the photographer they are a valuable personal asset.
To help photographers continue to use for many years the lens systems in
which they have invested their time, knowledge, and budgets,SIGMA has
developed original lens filters that meet the company's high standards
of excellence.
In developing its new protective lens filter,
SIGMA has leveraged an unprecedented cooperative relationship with a
glass manufacturer, resulting in a completely new type of glass called
Clear Glass Ceramic. Featuring this advanced material, the SIGMA WR
CERAMIC PROTECTOR is a highly reliable filter with outstanding
protective capability.
With many applications in aerospace and
other industries, glass ceramic is an extremely tough type of
crystallized glass that serves as the foundation for Clear Glass
Ceramic. While featuring the high transmittance required of optical
devices, this advanced new material combines greater hardness than
chemically strengthened glass and greater flexibility than sapphire
crystal glass. These qualities make Clear Glass Ceramic the ideal
material for protective lens filters.
Highly shock-resistant Clear Glass Ceramic
In the chemically strengthened glass used in conventional high-strength
protective filters, only the surface is strengthened through chemical
processes. In contrast, Clear Glass Ceramic is made with a special heat
treatment that precipitates microcrystals of a mineral called spinel
evenly throughout, giving the entire filter consistent strength.
Combining much greater hardness than chemically strengthened glass and
greater flexibility than sapphire crystal glass, Clear Glass Ceramic is
the ideal material for protective filters. Clear Glass Ceramic is also
resistant to cracking due to small scratches or chips. Since the risk of
shattering and producing fragments is reduced, it also offers an
enhanced level of safety.
Scratch-resistant
Clear Glass Ceramic offers a Vickers hardness number of 700HV.* This is a
level of hardness much higher than that of chemically strengthened
glass, which is used in conventionalhigh-strength protective filters.
Moreover, this higher level of hardness helps prevent scratches and
chips, which can lead to breakage of the filter. *In the Vickers
hardness test, a diamond instrument is pressed onto a material, and the
indentation so produced is used to calculate the hardness of the
material, which is expressed as a Vickers Pyramid Number (HV).
10 times the strength of a conventional protective filter, 3 times the strength of a chemically hardened glass filter
Made with a special process that evenly precipitates microcrystalline
spinel throughout the material, Clear Glass Ceramic offers a Vickers
hardness number of 700HV. The new SIGMA filter made with Clear Glass
Ceramic offers over 10 times the strength of a conventional protective
filter and over 3 times the strength of a high-strength protective
filter made with chemically hardened glass of the same thickness.
Thinner and lighter overall, thanks to advanced new material
Since Clear Glass Ceramic is extremely strong, the SIGMA WR CERAMIC
PROTECTOR is up to 50 percent thinner and weighs up to 30 percent less
than previous SIGMA filters while offering a higher level of strength.
High transmittance
SIGMA's Clear Glass Ceramic offers very high transmittance, making it ideal for use as optical glass.
High quality and compatibility with all SIGMA lenses
SIGMA has confirmed the compatibility of the SIGMA WR CERAMIC PROTECTOR
with all SIGMA lenses. In addition, SIGMA has confirmed that this
protective filter allows light to pass through evenly throughout the
image, from the center to the edges. All SIGMA lenses in its new lines
are checked with SIGMA's proprietary Modulation Transfer Function (MTF)
measuring system (A1)* using 46-megapixel Foveon direct image sensors,
and the SIGMA WR CERAMIC PROTECTOR is also manufactured to meet this
same exacting standard.
Water-repellent (WR) coating
The WR coating reflects only 0.24 percent of visible light, thereby
minimizing flare and ghosting. Its ability to repel both water and oil
is also excellent: water drops bounce right off, and fingerprints are
easily removed with a quick wipe. This coating also offers high
lubricating ability, giving it more than ten times the
scratch-preventing capability of SIGMA's current Super
Multi-LayerCoating. The coating's antistatic function helps prevent
static electricity from attracting dust and other particles, which can
easily be blown off the filter when they do adhere.
MADE IN JAPAN
The SIGMA WR CERAMIC PROTECTOR is made completely in Japan, including all individual processes used in its manufacture.