Is it necessary to use a reducing mirror to shoot waterfalls and running water with a slow door in photography? Otherwise, it will be overexposed?

If you want the waterfall to look like silk, you need to use a slower shutter speed. Whether to use a reduction mirror depends on the light of the scene. If the aperture is already small and the exposure is over, consider using a reducing mirror. In addition, because the shutter speed is very low, a tripod is needed to stabilize the camera.

In many cases, due to the intensity of external light, it is impossible to obtain a long enough shutter time. For example, when shooting water in the wild, we hope to use the shutter of 1 s to make the water appear as soft as cotton wool.

However, due to the strong light, that is, using the minimum aperture of the camera and the minimum ISO shooting, the shutter speed is still around 1/30 seconds. At this time, the only way is to use one or even two ND8 lenses to weaken the light entering the lens.

Extended data

Reducer classification series:

1, rotatable half mirror [R-HALF ND].

Half of this mirror is transparent, and the other half is ND4. 75% or equivalent to the second-order aperture of ND4 side cutting light. The lens is installed in a rotatable frame and can be adjusted horizontally. This kind of variable diameter mirror is used to deepen the sky tone or other occasions where the light intensity is quite different.

2. professional subtraction mirror ND 2.

PRO ND is the top-grade density reducer in the color filter market, and the filter has perfect color correction performance through metal evaporation process. PRO ND2 cuts the aperture by 1 or 50% of the light enters the camera.

3. professional subtraction mirror ND 4.

PRO ND is the highest density reducer in the color filter market. Through metal evaporation, it is made into a filter with perfect color correction performance. PRO NO4 can reduce the aperture by 2 levels or 75% of the light enters the camera.

Reference source: Baidu Encyclopedia -Reducer