Product Description
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Circular polarizing filters are made for all cameras with beam
splitters in the light paths of their TTL exposure meter and with
autofocus lenses. Circular polarization has the same pictorial
effect as linear polarization, but allows for proper exposure
metering and/or autofocus distance settings. The "high-end"
polarizing foils of the Käsemann-type filters are neutral in
color, they have a higher efficiency than conventional polarizing
foils and they are cemented between high-grade plane-parallel
optical glass. The resulting sandwich is then precision-polished
again to achieve highly accurate plane-parallel surfaces.
Subsequently they are edge-sealed to protect the foil against
humidity. Discriminating photographers regard the B+W
Käsemann-Type Polarizing Filter to be the very best of all
polarizing filters. They are well suited for applications that
require the highest possible imaging quality, especially with
high-speed telephoto lenses and apochromatic lenses.
From the Manufacturer
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Käsemann Circular Polarizers - The Highest Quality Polarizer
Available
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The images on the left was taken without any filter.
The image on the right was taken using a
B+W Circular Polarizer. Click for larger view.
( https://images-na.ssl-images-.com/images/G/01/electronics/filters/schneider/5_1_Large._.jpg )
The images on the left was taken without any filter.
The image on the right was taken using a
B+W Circular Polarizer. Click for larger view.
( https://images-na.ssl-images-.com/images/G/01/electronics/filters/schneider/5_2_Large._.jpg )
Circular polarizing filters are made for all cameras with beam
splitters in the light paths of their TTL exposure meter and with
autofocus lenses. Circular polarization has the same pictorial
effect as linear polarization, but allows for proper exposure
metering and/or autofocus distance settings.
Käsemann polarizing foils are neutral in color, have a higher
efficiency than conventional polarizing foils, and are cemented
between high-grade plano-parallel optical glass, using a special
cementing technique that resists delamination in humid climates.
The resulting sandwich is then precision-polished again to
achieve highly accurate plano-parallel surfaces. Discriminating
photographers regard the B+W Käsemann Polarizer as the very best
polarizer on the market. They are well suited for applications
that require the highest possible imaging quality, especially
with high-speed telephoto lenses and apochromatic lenses.
B+W Polarizers increase color saturation and reduce reflections.
The filter factor varies according to how the filter is
positioned in relation to the sun. Exposure compensation is about
two f-stops.
Why Use a Circular Polarizer?
-----------------------------
Modern DSLR cameras have a beam-splitting prism that sends part
of the incoming light to the meter and part to the viewfinder.
The effect is that the light entering the meter is partially
polarized by the beam-splitter. A linear polarizer placed on the
lens of such a system will act as a second polarizer and block
light to the meter by a degree dependent on the angle between the
prism and the polarizer on the lens. The result is incorrect
exposure/aperture values from the meter. That's why you need a
circular polarizer with such cameras. The circular polarizer
circumvents this problem by adding of a 1/4-wave retarder, or
delay foil. This ensures that the linearly polarized light is
changed into a rotation that appears unpolarized to the meter,
resulting in proper exposure/aperture readings.
MRC - A Special Scratch-Resistant, Water and Dirt Repelling
Coating
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The left half of this filter has a
traditional coating. The right half
has MRC coating. The lens elements of high-quality lenses and the
plano surfaces of filters require a perfect shape and smoothness
to achieve the best optical quality. Dirt, greasy fingerprints,
water marks and scratches reduce the image contrast and the
sharpness, which can result in blooming at light sources and have
an effect similar to a soft-focus lens. A clean front lens
element and clean filter surfaces are therefore an absolute
pre-requisite for demanding photographers.
MRC coating causes water
to bead up and slide right off. The MRC coating is first and
foremost a broadband anti-reflection coating. This means that its
reflection-reducing effect, which is thus also a
transmission-increasing effect, i.e. one which suppresses
scattered light and ghost images and transmits more light, has a
broadband action over the full spectrum. In contrast, the (almost
always blue) single-layer coating only has a high effect in the
medium wavelength range around yellow and yellow-green where the
eye is most sensitive to light, while its effect is greatly
reduced toward the blue-violet and purple-red end regions of the
visible spectrum. With the MRC coating, this blue, violet and red
to deep-red light cannot produce any contrast reducing scattered
light, spotty reflections or ghost images. A broadband effect can
only be achieved with a multilayer coating which requires a much
higher effort and precision because unevenness and irregularities
of the individual layers build up on one another and amplify one
another. Schneider therefore uses a plasma-assisted evaporation
coating process in which inert ions accelerated in an
electrical field compact the material deposited on the lens
surface in the vacuum chamber.
For photographers, the main advantage of MRC coating, is it's
ability to combat flare and ghosting. An added benefit is that
their filters remain free of dirt longer, so that they do not
have to be cleaned so often. When cleaning the filter does become
necessary, it is a lot easier to wipe off the dirt with a blower
brush, because of MRC's ability to repel dirt and moisture. This
also reduces the risk of micro-scratches which can occur during
cleaning.
Side view of F-Pro Rotating
. Click for larger view.
( https://images-na.ssl-images-.com/images/G/01/electronics/filters/schneider/F-Pro_Rotating__Large._.jpg )
F-Pro Brass Filter
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This filter uses a rotating B+W F-Pro filter for added
creative options. The has a front accessory thread and is
made of brass. Compared to the earlier standard , the F-Pro
, introduced in 2001, has become thinner. Now it can be used
with wide angle lenses, including most 24mm focal lengths on a
full frame body, without vignetting. Another advantage of the
F-Pro is its modified retaining ring, which is no longer
threaded in from the front, but holds the filter glass in place
from the back. When removing a filter or lens hood that has been
screwed on too tight to the filter, the retaining ring is not at
risk of loosening.
- This filter uses our standard B+W F-Pro filter , which has a front accessory thread and is made of brass..
- MRC by B+W is not only an extraordinarily effective multiple layer coating, it is also harder than glass, so that it protects filters from scratches, and it is also water and dirt repellent, thus facilitating filter maintenance..
- Manufactured from Water-White Schott Glass.