The Neutral Density (ND) filter is a great tool for photographers to have in their arsenal. It works like sunglasses for your camera lens, blocking part of the incoming light and allowing you to take better pictures in bright light. ND filters are also useful for creating longer exposures, blurring moving objects, and darkening part of the image. A clear ND filter can last one or two steps, while a very dense ND filter can last 15 or 20 steps.
Neutral density (ND) filters are essential tools for photographers looking to control light and create unique, creative effects in their images. By reducing the amount of light entering the camera lens, ND filters allow you to use slower shutter speeds or wider apertures in bright conditions, opening up a world of possibilities for long exposure photography, shallow depth of field effects, and more.
In this comprehensive guide, we'll explore the fundamentals of neutral density filters, including how they work, the different types of ND filters available, and how to choose the right ND filter for your needs. We'll also cover essential techniques for using ND filters, such as calculating exposure, focusing, and avoiding common problems. Finally, we'll explore some creative applications of ND filters, from long exposure landscapes to smooth water effects, and provide tips for getting started with these powerful photographic tools.
How Neutral Density Filters Work
Neutral density filters work by reducing the amount of light that enters your camera lens, allowing you to use slower shutter speeds or wider apertures than would otherwise be possible in bright conditions. This light reduction is achieved through the use of a darkened, neutral-colored glass or resin that evenly absorbs light across all wavelengths.
Light Reduction and Density
The amount of light reduction provided by an ND filter is expressed in terms of density or stops. A one-stop ND filter (also known as an ND2 or 0.3 density filter) reduces the amount of light entering the lens by half, while a two-stop filter (ND4 or 0.6 density) reduces the light by a factor of four. Higher-density filters, such as 10-stop (ND1000 or 3.0 density) filters, can reduce the light by a factor of 1000, allowing for extremely long exposures even in bright daylight.
Neutral Color and Image Quality
True neutral density filters are designed to reduce light evenly across all wavelengths, maintaining a neutral color balance and minimizing any impact on image quality. However, some lower-quality or higher-density ND filters may introduce a slight color cast, which can be corrected in post-processing or by using a custom white balance setting.
Types of Neutral Density Filters
There are three main types of neutral density filters: solid, graduated, and variable. Each type has its own unique characteristics and applications.
Solid Neutral Density Filters
Solid ND filters, also known as full ND filters, have a uniform density across the entire surface of the filter. They are available in a range of densities, from 1-stop to 20-stops or more, and are the most common type of ND filter used for long exposure photography and controlling depth of field.
Some popular solid ND filters include:
LEE Filters Big Stopper (10-stop)
B+W ND 3.0 (10-stop)
Hoya ProND (2, 4, 8, and 16-stop options)
Graduated Neutral Density Filters
Graduated ND filters (GND filters) have a gradient of density that transitions from dark to clear across the surface of the filter. They are designed to balance the exposure between a bright sky and a darker foreground in landscape photography, allowing for a more even exposure without the need for post-processing techniques like exposure blending.
GND filters are available in different densities and transition types, such as soft-edge or hard-edge, to suit various shooting situations. Some popular GND filters include:
LEE Filters Soft-Edge Graduated ND (0.3, 0.6, 0.9 densities)
Singh-Ray Reverse Graduated ND (1, 2, 3 stop options)
Variable Neutral Density Filters
Variable ND filters, also known as adjustable ND filters, allow you to adjust the density of the filter by rotating the front element. These filters consist of two polarizing elements that, when rotated, can increase or decrease the amount of light reduction.
Variable ND filters offer the convenience of having multiple densities in a single filter, but they may introduce some image quality issues such as color casts or cross-polarization effects at higher densities. Some popular variable ND filters include:
Tiffen Variable ND (1 to 8 stops)
PolarPro Peter McKinnon Variable ND (6 to 9 stops)
Choosing the Right Neutral Density Filter
When selecting a neutral density filter for your photography needs, consider the following factors:
Filter Density and Stops
Choose the appropriate density or number of stops based on the amount of light reduction you need for your intended application. For general long exposure photography, a 6-stop or 10-stop filter is a good starting point, while for extreme long exposures or very bright conditions, a 15-stop or 20-stop filter may be necessary.
Filter Size and Compatibility
Ensure that you choose a filter size that matches the diameter of your lens's front element. Common filter sizes include 49mm, 52mm, 58mm, 62mm, 67mm, 72mm, 77mm, and 82mm. If you have multiple lenses with different filter sizes, consider investing in a filter system with adapter rings or using step-up/step-down rings to use a single filter on multiple lenses.
Filter Quality and Brand
Invest in high-quality ND filters from reputable brands to ensure optimal image quality and minimize issues like color casts, vignetting, or loss of sharpness. Some well-regarded ND filter brands include LEE Filters, B+W, Singh-Ray, Hoya, and Breakthrough Photography.
Essential Techniques for Using Neutral Density Filters
To effectively use neutral density filters in your photography, master these essential techniques:
Calculating Exposure with Neutral Density Filters
When using an ND filter, you'll need to adjust your exposure settings to compensate for the reduced light entering the camera. To calculate the new exposure time, use the following steps:
Determine the base exposure without the ND filter.
Calculate the number of stops of light reduction provided by your ND filter.
Multiply the base exposure time by 2^(number of stops) to get the new exposure time.
For example, if your base exposure is 1/60 seconds and you're using a 6-stop ND filter, the new exposure time would be 1/60 × 2^6 = 1 second.
Alternatively, you can use a long exposure calculator or mobile app to determine the appropriate exposure settings for your ND filter.
Focusing with Neutral Density Filters
Autofocus may struggle to lock onto a subject when using an ND filter, especially with higher-density filters. To ensure accurate focus, follow these steps:
Compose your shot and set your focus without the ND filter in place.
Switch your lens to manual focus to prevent the camera from refocusing when you add the filter.
Carefully attach the ND filter to your lens, taking care not to bump the focus ring.
Double-check your focus and composition, then take the shot.
Using a Tripod and Remote Shutter Release
When using ND filters for long exposure photography, a sturdy tripod and remote shutter release are essential to minimize camera shake and ensure sharp images. Set up your tripod on a stable surface, use a cable release or wireless remote to trigger the shutter, and enable mirror lockup (if available) to further reduce vibrations.
Avoiding Common Problems with Neutral Density Filters
Some common issues to watch out for when using ND filters include:
Vignetting: Thick or stacked filters may cause darkening of the image corners, especially on wide-angle lenses. Use slim-profile filters or a larger filter size with adapter rings to minimize vignetting.
Light leaks: Ensure that your ND filter is securely attached to the lens and that there are no gaps that could allow light to leak in and cause flare or reduced contrast.
Dust and smudges: Keep your ND filters clean and free from dust, smudges, and fingerprints to maintain image quality. Use a microfiber cloth and cleaning solution designed for optical surfaces to gently clean your filters.
Creative Applications of Neutral Density Filters
Neutral density filters open up a world of creative possibilities for your photography. Here are some popular applications:
Long Exposure Landscapes
Use ND filters to create dreamlike, ethereal landscapes with blurred clouds, smooth water, and softened foliage. Experiment with different exposure times to achieve various effects, from gently blurred clouds to completely smooth, misty water.
Smooth Water Effects
ND filters are essential tools for creating silky smooth water effects in waterfalls, rivers, and seascapes. Use a 6-stop or 10-stop filter to lengthen your exposure time and blur the motion of the water, creating a serene and otherworldly atmosphere.
Blurring Moving Subjects
In busy urban environments, ND filters can be used to blur moving subjects like pedestrians or vehicles, creating a sense of motion and energy in your images. Use a tripod and a slower shutter speed to capture the hustle and bustle of city life in a unique and creative way.
Shallow Depth of Field in Bright Light
ND filters allow you to use wider apertures in bright conditions, making it possible to achieve a shallow depth of field and beautiful background blur (bokeh) even in midday sun. This technique is particularly useful for outdoor portraits or product photography.
Getting Started with Neutral Density Filters
If you're new to using neutral density filters, here are some tips to help you get started:
Essential Equipment
To begin your ND filter journey, you'll need the following essential equipment:
A set of solid ND filters in various densities (e.g., 3-stop, 6-stop, 10-stop)
A sturdy tripod and head
A remote shutter release (cable release or wireless remote)
A filter holder and adapter rings (if using square or rectangular filters)
A microfiber cleaning cloth and cleaning solution
Practice and Experimentation
The best way to learn how to use ND filters effectively is through practice and experimentation. Start by using a 3-stop or 6-stop filter in a familiar location, and gradually work your way up to higher-density filters and more challenging shooting situations. Don't be afraid to try different compositions, exposure times, and creative techniques to find what works best for your photographic style.
Inspiration and Learning Resources
To further your knowledge and find inspiration for your ND filter photography, explore the following resources:
The Ultimate Guide to Long Exposure Photography
A Step-by-Step Guide to Long Exposure Photography
The Creative Photographer's Guide to Neutral Density Filters
The Long Exposure eBook by Brent Purves
The Photography Show: ND Filters for Long Exposure (YouTube video tutorial)
Conclusion
Neutral density filters are powerful tools that every photographer should have in their kit. By reducing the amount of light entering your camera lens, ND filters allow you to control exposure, depth of field, and motion blur in ways that would otherwise be impossible in bright conditions. Whether you're a landscape photographer looking to create dreamy, ethereal scenes or a portrait photographer seeking to achieve beautiful background blur in midday sun, ND filters offer endless creative possibilities.
To make the most of your ND filters, invest in high-quality filters from reputable brands, master the essential techniques for calculating exposure and focusing, and don't be afraid to experiment with different densities, compositions, and creative applications. With practice and patience, you'll soon be creating stunning, long-exposure masterpieces that capture the world in a unique and captivating way.
FAQs
What is the difference between a solid ND filter and a graduated ND filter?
A solid ND filter has a uniform density across the entire surface of the filter, reducing light evenly for the whole image. A graduated ND filter has a gradient of density that transitions from dark to clear, allowing you to selectively darken bright areas of the image (like the sky) while maintaining normal exposure for the rest of the scene.
Can I stack multiple ND filters to achieve higher density?
Yes, you can stack multiple ND filters to achieve higher density and longer exposure times. However, stacking filters may increase the risk of vignetting, light leaks, and reduced image quality. It's generally better to use a single, high-density filter (like a 10-stop or 15-stop filter) for extremely long exposures.
How do I avoid color casts when using ND filters?
To minimize color casts, invest in high-quality ND filters from reputable brands that are designed to maintain neutral color balance. If you still notice a color cast in your images, you can correct it in post-processing using white balance adjustments or by creating a custom camera profile for your specific filter.
Can I use ND filters for video recording?
Yes, ND filters can be used for video recording to control exposure, depth of field, and motion blur. When using ND filters for video, be sure to choose filters with a low optical density (1-3 stops) to avoid creating overly dark or long exposures that may result in choppy or unnatural-looking footage.
How do I clean and store my ND filters?
To clean your ND filters, use a soft, microfiber cloth and a cleaning solution designed for optical surfaces. Gently wipe the filter in a circular motion, taking care not to apply too much pressure or scratch the surface. Store your filters in a protective case or pouch when not in use, and avoid stacking them together without a protective layer in between to prevent scratches.
Sources and References
- "The Ultimate Guide to Neutral Density Filters." Fstoppers, fstoppers.com/originals/ultimate-guide-neutral-density-filters-228166.
- "A Complete Guide to Neutral Density Filters." CaptureLandscapes, www.capturelandscapes.com/neutral-density-filters/.
- "The Ultimate Guide to Neutral Density Filters for Long Exposures." Digital Photography School, digital-photography-school.com/ultimate-guide-neutral-density-filters-long-exposures/.
- "Understanding Neutral Density Filters." Cambridge in Colour, www.cambridgeincolour.com/tutorials/neutral-density-filters.htm.
- "10 Stop ND Filters: 5 Ways to Conquer the Big Stopper." SLR Lounge, www.slrlounge.com/10-stop-nd-filter-5-ways-to-conquer-the-big-stopper/.
- "The Creative Photographer's Guide to Neutral Density Filters." B&H Explora, www.bhphotovideo.com/explora/photography/tips-and-solutions/a-creative-photographers-guide-to-neutral-density-filters.
- "A Step-by-Step Guide to Long Exposure Photography." PetaPixel, petapixel.com/2014/03/17/step-step-guide-long-exposure-photography/.
- "The Long Exposure eBook." Brent Purves, www.brentpurves.com/ebook.
- "ND Filters: The Essential Guide for Photographers." Photography Life, photographylife.com/nd-filters-guide.
- "Mastering the Art of Long Exposure Photography with ND Filters." DPReview, www.dpreview.com/tutorials/1943534964/mastering-the-art-of-long-exposure-photography-with-nd-filters.
By understanding the fundamentals of neutral density filters, mastering essential techniques, and exploring creative applications, you'll be well-equipped to unlock the full potential of these powerful photographic tools. Remember to invest in quality filters, practice regularly, and draw inspiration from the work of other photographers as you embark on your own ND filter journey. With time and dedication, you'll be creating stunning, long-exposure images that showcase the world in a truly unique and captivating way.
Summary
Ten- and fifteen-step filters are great for removing moving objects from an image. Graduated filters are useful when you only want to darken part of the image, such as when the sky is brighter than the foreground. Square filters also have more surface area, which means more area of moisture accumulation when recording near the ocean, waterfalls, or in the rain. To use an ND filter, it is placed in front of the lens and blocks part of the incoming light. If there's a lot of light, you might be able to measure exposure through the filter, but if you're shooting at the end of the day, you might have to calculate the exposure manually.
A filter system can take a little longer to set up and, when the lighting is good, you want to take the picture, not fight with your equipment .Photographers who have extensive knowledge of Photoshop can compose an image using a quick shot that was taken without the ND filter and another that was taken with the ND filter. It's always a good idea for DSLRs to cover the camera's eyepiece, especially if the sun is behind the camera. Since portrait photographers tend to use a very small depth of field (open aperture), it may not be convenient to reduce exposure with the aperture and, if the ISO is already at maximum, the next best option is to use a one- or two-step neutral density filter. Once again, both have been exposed to exactly the same amount of light, but with the ND filter in place you can let light in slowly, which allows moving things to blur out, like clouds, and also allowing things to mix, like waves in water.
