Lens filters are divided into different types according to their effects, and we will introduce the role of ND filters that adjust the amount of light in the lens and how to recommend filter selection.
1. What is a lens filter?
Lens filters are filters that are mounted on interchangeable lenses of DSLR cameras or mirrorless single-lens cameras, and there are two main types of lenses. They are "protective filters" that protect lenses and "special effects filters" that aid photographic expression. Among them, ND filters belong to special effect filters. First, let's briefly introduce the types of effect filters.
(1). ND (Neutral Density) filters
The ND (Neutral Density) filter is a sunglasse-like filter that adjusts the amount of light entering the lens. For example, you can use a slow shutter speed to take beautiful photos.
With ND filter
No ND filters
(2).PL(偏振)滤光片
PL (polarization) filters are filters that suppress reflections from glass, water surfaces, etc. By controlling the reflected light, vivid colors and contrast can be expressed.
With PL filter
No PL filter
(3). Cross filter
A cross filter is a filter that expands the light of a strong point source and emphasizes the sparkle, and it makes the reflection of the water surface and the sunlight through the trees and other rays sparkle.
With cross filter
No cross filter
(4). Color filter
Color filters are filters that adjust color and contrast, and you can also take clear, nostalgic photos.
With color filters
No color filters
2. What you need to know before buying ND filters
ND filters are mainly used to control exposure. Here we will explain the three elements that control exposure: aperture, shutter speed, and ISO sensitivity. Exposure is basically controlled by changing these three elements, but the fourth element is the ND filter.
(1). Aperture
Aperture is the control of the amount of light that passes through the lens. Usually, by changing the size of the hole on the lens, you can change the amount of light that passes through it. It is generally expressed by a value called the "F-number", the smaller the value, as in F1.4, the more light passes through (the hole in the aperture becomes larger), and the larger the value, such as F11, the more light passes through (the hole in the aperture becomes larger), the less light passes through.
(2). Shutter speed
The shutter is a way to adjust the amount of time the light hits the sensor, and the time the shutter is open is called the shutter speed. If you want to take a photo of the same brightness, if the amount of light entering is doubled (one step smaller than the F-number), the time will be halved. For example, brightness at F2.8 and shutter speed 1/60. Photos taken at F4 and 1/30 are the same size (ISO sensitivity is fixed). In addition, deliberately blurring the subject by using a slow shutter speed (e.g., one second) is often used along with bokeh as a means of expression specific to photography.
(3). ISO sensitivity
ISO sensitivity is the intensity of the sensor's response to light. The higher the ISO speed, the better the sensitivity (the higher the sensitivity), allowing you to take photos with less light and faster shutter speeds. In general, the higher the sensitivity, the more noise is produced and the image quality deteriorates, so shooting at the lowest possible ISO sensitivity will result in better image quality.
3. When should you use ND filters
There are two main situations in which ND filters are used in photography. One is when using a slow shutter speed during the day. When representing water currents such as waterfalls, you fix the camera on a tripod and use a slow shutter speed, but if you're trying to get a proper exposure, even the minimum aperture and minimum ISO sensitivity aren't enough. In this case, the ND filter is used as the fourth element to control the exposure.
Another case for using an ND filter is to use a lens with a smaller F-number to increase bokeh in bright conditions. In this case, even if the ISO sensitivity is set to the lowest, the shutter speed will still exceed the maximum speed, so the ND filter is used as the fourth element. This happens quite often, so if you're using a wide-aperture lens during the day, you may have to carry an ND filter.
4. How to choose ND filters
We'll explain how to choose an ND filter, so choose the best ND filter based on your shooting purpose and use.
(1). Check the lens filter size
As with any filter, be sure to check the size of the lens you're using when choosing an ND filter. If you're mounting it to multiple lenses, we recommend matching it to the largest filter diameter. A tool called the Boost Ring makes it easy to attach a large filter to a lens with a smaller filter aperture, so you can reuse one filter. Some of the latest lens series have a uniform filter aperture, so if you're shooting video or other situations where ND filters are commonly used, we recommend choosing one of these lens series.
(2). Think about your purpose
ND filters are required in limited cases. This feature is required when using lenses with wide aperture f-numbers, when using slow shutter speeds during the day (e.g., when representing water currents), and when shooting full-size videos. For these types of lenses, you'll almost always need ND filters.
(3). ND filter values and how to choose
The value of ND filters depends on the amount of light they can reduce. For example, ND16 indicates that there are four levels of light reduction: no filter→ ND2→4→8→16. With typical ND filter values ranging from 2 stops (ND4) to 6 stops (ND64), modern digital cameras have high sensitivities, can be used in a wide ISO sensitivity range, and are equipped with image stabilization, so you generally don't have to worry about overpowering the values.
(4). How to choose ND filter when shooting video
When shooting video, it's almost impossible to change the shutter speed from around 1/30 to 1/60. Since the aperture is used to adjust the focus range, the exposure is basically adjusted with ISO sensitivity and ND filters. In addition, since the image quality will be better when shooting videos at lower sensitivities, it is necessary to use multiple ND filters with different values.
(5). Convenient variable ND filter
Video shooting requires an ND filter with multiple values, but there is a filter that lets you change the values with a single filter. Variable ND filter. If you use variable ND filters of unreliable quality, you may encounter problems such as uneven colors, so we recommend buying products from major manufacturers.
5. 5 recommended ND filters
(1). Kenko PRO1D Lotus ND
The Kenko PRO1D Lotus ND series has a waterproof and oil-repellent coating. ND filters are often installed and removed and can be easily touched and soiled, so an easy-to-clean water- and oil-repellent coating is one of the most effective filters. Of course, it's a great ND filter that's not only easy to use, but also performs well without compromising color balance.
(2).marumi EXUS ND
This is the ND filter from the marumi high-performance filter series "EXUS". Thanks to the use of high-quality glass and high-performance coating, it is a product that can be used with peace of mind. It has a lot of variations in terms of values and apertures, and it has a good balance in terms of quality, performance, and price, so it is also recommended for video users who need to prepare multiple ND filters.
(3). NiSi ND TRUE COLOR ND VARIO
This is a variable ND filter that allows you to adjust the ND density on a scale of 1 to 5 (ND2 to 32). The built-in stop suppresses the occurrence of X-shaped unevenness, and even when a filter is attached, the hue is maintained as the main lens. Also attractive are the nano-coatings that dampen ghosting and glare, as well as the water-repellent and stain-repellent coating that is easy to maintain.
(4).dirty磁性方形过滤器
The Marumi Magnetic Square Filter Series is a square filter that can be installed and removed with a light touch of a magnet. It has a variety of variations, including not only ND filters but also semi-ND filters, making advanced filter work possible. Semi-ND is especially useful because it allows you to adjust the filter by moving it up and down, even if the boundary between brightness and darkness is not in the center.
(5). Kenko NDX II
Variable ND filters are popular ND filters among video users that let you change the effects. Kenko Variable NDX can change the effect from ND2.5 to ND450 equivalent (usage range), so a single filter can handle most situations where an ND filter is required. Although the price is a bit expensive, it is a product that is supported by professional photographers due to its high quality.
6. How to maintain ND filters
ND filters are frequently installed and removed and are more prone to dirtiness than other filters, so they must be cleaned frequently. ND filters are maintained in the same way as lenses and other filters, such as blowing off dust with a hair dryer and then wiping off dirt with lens cleaning paper. Also, since video users often touch the camera while shooting, it is easy to get scratches, so it is recommended to replace them regularly. #夏日生活打卡季#