Walimex pro ND2 Neutral Density Filter 100x100mm

Explanation Neutral density filters

Neutral density filters (ND filters) reduce the entire visible light spectrum evenly across the entire filter. This reduction is useful in a variety of applications. The neutral density filter used here with a filter factor of 2 extends the exposure time/aperture by the f-stop value 1.

Exposure time when filming

The frame rate of old cinema film cameras used to be 24 frames per second. At that time, the exposure was usually 1/48 sec. Half of the time was exposed, the other half the camera needed to transport the film.

Today's cameras are more flexible. Almost any exposure time is possible. You should only not expose longer than the exposure time of a picture (here 1/24 sec). However, if you expose for too short a time, e.g. 1/240 sec (1/10 of the 24 frames per second), 9/10 of the time the image is not exposed. Thus, the film ‘misses’ a large part of the movement. You get a so-called ‘staccato effect’ and the film appears jerky. That is why most filmmakers rely on the rule of thumb: shutter speed = frame rate / 2.
If you still want to film with an open aperture in sunshine and avoid this effect, we recommend using a neutral density filter (ND filter). This ensures that less light reaches the chip through the lens. ND filters are available in different strengths. We offer reductions of 50%, 75% and 87% of the light incidence. The right filter must be calculated or tried out depending on the shooting situation.