ND filters explained: What are ND filters for and how to use them correctly
ND filters are among the most important tools in landscape and long-exposure photography. But many beginners wonder: What are ND filters actually for? And, most importantly, how do they work correctly? Here you'll find all the answers – detailed, practical, and understandable.
What is an ND filter?
ND stands for neutral density . An ND filter is simply a tinted glass pane that absorbs light evenly without altering the colors or contrast of your image. This darkening automatically extends the exposure time.
Unlike polarizing or graduated filters, an ND filter always affects the entire image—comprehensively and neutrally. The strength of the effect is specified in so-called "f-stops" or as an ND value (e.g., ND8, ND64, ND1000).
What do you need ND filters for?
ND filters are used whenever you intentionally want to shoot with longer exposure times—even in daylight. Typical applications:
- 🌊 Blur water: Flowing rivers, waterfalls, lakes and the sea appear soft, velvety and mirror-smooth with long exposure times.
- 🌥️ Make cloud movements visible: Long-moving clouds create dramatic, dynamic sky moods.
- 🚶♂️ Make moving crowds disappear: In busy city centers, people can be “magically disappeared” with long exposures.
- 🚗 Show vehicles as light trails: Fascinating light trails are created, especially in night shots.
- 🎯 Use a large aperture in bright light: Even in sunny weather, you can use an ND filter to take wide-open photos, for example for portraits with beautiful background blur.
ND filter strengths – which filter for what?
The stronger the filter, the more light is reduced. Here's a rough overview:
- ND8 (3 f-stops): slight extension, ideal for subtle effects in cloudy conditions
- ND64 (6 f-stops): strong reduction, perfect for soft water in daylight
- ND1000 (10 f-stops): extreme darkening, allows long exposures even in bright sunlight
Depending on the subject and lighting conditions, the filters can also be combined with each other to achieve even longer exposure times.
How do you use an ND filter correctly?
Working with ND filters requires some preparation. Here's how to proceed:
- First, adjust the image section, focus and composition without any filters.
- Calculate the new exposure time based on the desired extension (e.g. using an app or ND calculator).
- Carefully insert the ND filter onto your lens or into the filter system.
- It is best to switch to manual mode (M) to set the exposure time and aperture precisely.
- Ideally, use a remote shutter release and a stable tripod to avoid camera shake.
- Check the result and adjust the exposure time slightly if necessary.
Tip: Autofocus may have difficulty with very strong ND filters. In this case, focus without the filter first and then switch to manual focus.
Round filter or filter holder system?
ND filters are available as classic screw-in round filters as well as in a filter holder system with rectangular filters. Both systems have their strengths:
- ✅ Round filter: compact, quick to install, ideal for travel & everyday use
- ✅ Filter holder system: maximum flexibility, perfect for combination with graduated filters (GND), exact positioning
You can find more information here: Filter holder systems for maximum control
✅ Our recommendation for high-quality ND filters
When purchasing ND filters, quality is key. Poor-quality filters can cause color casts, reflections, or image blur. Look out for:
- ✅ High-quality HD glass
- ✅ Multi-coating against reflections
- ✅ Nano-coating against dirt & water
- ✅ Precise, slim frame (Ultra Slim)
FILTERFOTOGRAF® offers top-quality ND filters for the highest demands:
FILTERFOTOGRAF® – because every detail counts.