Photography guide

How to use ND filters

An ND filter reduces light so you can lengthen shutter speed or open aperture. Strength is expressed in stops or manufacturer codes.

Core principle

An ND filter reduces light so you can lengthen shutter speed or open aperture. Strength is expressed in stops or manufacturer codes.

Practical workflow

Set framing and focus before mounting a very dark filter, then calculate the new exposure.

1. Define the image goal and working conditions.
2. Choose baseline settings and make a test frame.
3. Check focus, histogram and critical image areas.
4. Record the settings that worked and why you changed them.

What to verify before finishing

For long exposures, check light leaks and refine exposure from the histogram.

Do not treat a single rule as a guarantee. Conditions, equipment design and output size change the requirements. Record settings and conclusions in the AparatTo planner.