Variable ND Filters

A Variable ND (Neutral Density) Filter is primarily used to control the amount of light entering the camera. It provides variable light reduction by allowing you to adjust the density of the filter, making it versatile for different lighting conditions and achieving creative effects like motion blur in bright environments.

A Variable ND filter typically has two polarizing layers that can be rotated against each other to adjust the strength of the filter. By rotating the outer ring of the filter, you can increase or decrease the density, thus controlling the amount of light that passes through the lens. This rotation allows you to adapt to changing lighting conditions without changing the filter itself.

While it's technically possible to stack a polariser and a variable ND filter, it's generally not recommended. Both filters affect the polarization of light, and stacking them can lead to undesirable interactions, such as uneven polarization, color shifts, and reduced image quality. Instead, if you need the effects of both filters, consider using a combination filter that integrates both polarizing and ND properties in a single unit for more consistent results.

A standard ND (Neutral Density) filter has a fixed level of light reduction, providing a consistent reduction in brightness. In contrast, a Variable ND filter allows you to adjust the strength of the filter by rotating its outer ring, providing variable light reduction. The Variable ND filter offers more flexibility in adapting to changing lighting conditions without changing the filter itself, making it a versatile tool for different shooting scenarios.