HR 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.