09 Dec 2013

Circular Polarizing Filter

HR Digital CPL super MCcpl-2
Digital pro CPL MC

When light is incident on a surface, it is partly reflected. With a slanting incidence of light, it is also more or less polarized  provided that the surface is not electrically conductive like glass, plastic or lacquer or is hardly electrically conductive like  water (whose conductivity is low relative to that of metals) . The polarization increases with the angle of incidence, reaches a  maximum at around 55° and then drops again.

Electrically conductive surfaces, e .g . blank metal, do not cause polarization . If the metal is lacquered or has an insulating  coating, polarization arises at the insulating layer, e .g . aluminum which forms a non-conductive aluminum oxide layer at air.

A polarization filter only transmits light oscillating at a specific direction without hindrance; in the case of light oscillating obliquely thereto, only the portion oscillating in this direction; it is therefore attenuated . Light oscillating transversely to the direction of polarization is blocked . Consequently, reflections can be reduced or even fully eliminated at an ideal angle of incidence of around 55° . Conversely, reflections can also be amplified up to twice the brightness, e.g. for more intensive sun reflections on water, using the filter if it is rotated by 90° from the maximum attenuation.

The blue light of the sky reflected e.g. from red roofs, green grass and foliage is polarized . Landscape shots taken with a polarization filter therefore allow the blue tinge to be reduced and thus produce a better color saturation for purer colors . Blue light from the sky can be intensified using a polarization filter rotated into a suitable position (to emphasize white clouds) because it is highly polarized above all in a direction of view of around 90° to the sun .

The Circular Polarization Filter requires 1 .5 f/stops as a correction .

cpl-grafik

cpl-contoh

 

HR Digital CPL super MC
Best optical glass · perfect optical surface quality · multi-coated ·
high polarizing efficiency · color neutral transmission · extremely scratch resistant · liquid and dirt-repellent coated · rugged slim brass ring with front thread · wide-angle compatible

Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 / 86 / 95 mm

Digital pro CPL MC
Best optical glass · perfect optical surface quality · multi-coated · high polarizing efficiency · color neutral transmission · very scratch resistant · rugged slim ring with front thread · WA compatible

Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 mm

 

09 Dec 2013

Neutral Density Filters nd-prod

2x, 4x, 8x

 

nd-lensHR Digital ND 0,3/2x, 0,6/4x, 0,9/8x MC

 

Every photographer normally wants bright Light However, when fast motion is to be illustrated by blurring, it is sometimes too bright for the longer exposure time required for the “smear effect”. The exposure time could admittedly often be extended by stopping down more, but then increasing diffraction would reduce the sharpness (see page 15 below).

 

Sometimes, it can be too bright to stop up for low depth of field, e.g.for a sharp person against a blurred background.

 

These problems can be solved easily using the HR Digital neutral density filters with color-neutral light attenuation available from  Rodenstock.They allow an exposure extension by a factor of 2, 4 or 8 for impressive smear effectson a further opening of the aperture by one, two or three stops for a much reduced depth of field.The number 0.3, 0.6, and 0.9 on the filter frame indicates the “logarithmic density” of the respective filter.

 

The ND 4x filter would e.g. allow an exposure time of 1/250 s instead of 1/1000 s, which allows fill-flash, for a portrait of low depth of field at f/stop 2.8. Or a longer exposure time of 1/60 s  could be set at f/stop 5. 6 instead of 1/250 s, which is absolutely necessary for the panning smear effect in car racing.

 

If you only buy one ND filter, you should buy the most versatile ND

4x filter. It will then become clear in practice whether an ND 2x or

an ND 8x may be necessary (for even higher values, see Digital

Vario ND on pages 14 and 15).

 

Rodenstock gray filters ensure perfect sharpness and, thanks to

spectrally balanced damping, neutral color reproduction.

 

nd-grafik

nd-gambar1

 

nd-gambar2

 

HR Digital ND 0,3/2x, 0,6/4x, 0,9/8x  MC

Best optical glass · perfect optical surface quality · multi-coated · color neutral reduction of light  intensity · very scratch resistant · rugged slim brass ring with front thread · wide-angle compatible.

 

Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 mm

 

 

09 Dec 2013

Circular Polarizing Filter

HR Digital CPL super MCcpl-2
Digital pro CPL MC

When light is incident on a surface, it is partly reflected. With a slanting incidence of light, it is also more or less polarized provided that the surface is not electrically conductive like glass, plastic or lacquer or is hardly electrically conductive like water (whose conductivity is low relative to that of metals) . The polarization increases with the angle of incidence, reaches a maximum at around 55° and then drops again.

Electrically conductive surfaces, e .g . blank metal, do not cause polarization . If the metal is lacquered or has an insulating coating, polarization arises at the insulating layer, e .g . aluminum which forms a non-conductive aluminum oxide layer at air.

A polarization filter only transmits light oscillating at a specific direction without hindrance; in the case of light oscillating obliquely thereto, only the portion oscillating in this direction; it is therefore attenuated . Light oscillating transversely to the direction of polarization is blocked . Consequently, reflections can be reduced or even fully eliminated at an ideal angle of incidence of around 55° . Conversely, reflections can also be amplified up to twice the brightness, e.g. for more intensive sun reflections on water, using the filter if it is rotated by 90° from the maximum attenuation.

The blue light of the sky reflected e.g. from red roofs, green grass and foliage is polarized . Landscape shots taken with a polarization filter therefore allow the blue tinge to be reduced and thus produce a better color saturation for purer colors . Blue light from the sky can be intensified using a polarization filter rotated into a suitable position (to emphasize white clouds) because it is highly polarized above all in a direction of view of around 90° to the sun .

The Circular Polarization Filter requires 1 .5 f/stops as a correction .

cpl-grafik

cpl-contoh

 

HR Digital CPL super MC
Best optical glass · perfect optical surface quality · multi-coated ·
high polarizing efficiency · color neutral transmission · extremely scratch resistant · liquid and dirt-repellent coated · rugged slim brass ring with front thread · wide-angle compatible

Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 / 86 / 95 mm

Digital pro CPL MC
Best optical glass · perfect optical surface quality · multi-coated · high polarizing efficiency · color neutral transmission · very scratch resistant · rugged slim ring with front thread · WA compatible

Sizes: 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 mm

 

09 Dec 2013

UV/IR Blocking Filteruv-logo

 

HR Digital UV/IR

 

uv-lensDigital camera sensors are also somewhat sensitive to ultra iolet radiation (UV) and to a high degree to infrared radiation (IR). A corresponding blocking filter in front of the sensor is therefore required for correct-color digital shots. It also serves as a protection for the microlens elements and the RGB Bayer filter (chessboard-like array of tiny red, green and blue filters which allocates one of the three RGB colors to each pixel).

Its blocking effect is unfortunately not sufficient for some digital cameras and specifically not for  older digital cameras. This means that with a high infrared portion in the light chlorophyll can appear too bright because it is highly reflective for IR radiation.

Furthermore, false colors then arise because not only the red color, but also the green and blue colors of the RGB Bayer filter are transmissible for infrared. A reddish tinge, such as is initially expected, therefore does not always have to occur. Whether only a brightening occurs or also false colors and the strength of the two features depend on the efficiency of the camera’s internal IR blocking filter and on the IR transmissibility of the individual RGB filters.

Furthermore, if the IR transmissibility is too high, blur can also occur because the lens is not corrected for IR.

Using the Rodenstock UV/IR blocking filters means that you are always on the safe side both for a far view with a high portion of UV radiation (see pages 8 and 9 for more details) and in intensive sunshine with a high degree of IR reflection by chlorophyll. It blocks UV and IR radiation with a steep flank and ensures true colors.

Cameras with a sensor modified for infrared shots or astronomical H-alpha shots always require an external UV/IR blocking filter for use for normal true-color shots.

The UV/IR blocking filter does not require any exposure correction.

uv-grafik

uv-gambar1

uv-gambar2

Water absorbs infrared radiation. Therefore, the reflections of the trees on the water keep green even without a UV/IR blocking filter.

HR Digital UV/IR.

Best optical glass · perfect optical surface quality · color neutral · steep-edged interference filter · very scratch resistant · rugged slim brass ring with front thread · wide-angle compatible

Sizes: 37 / 39 / 40,5 / 43 / 46 / 49 / 52 / 55 / 58 / 62 / 67 / 72 / 77 / 82 mm