1, circular filter: a filter that can be screwed directly in front of the lens, such as UV mirror, polarizer and ND filter. Moreover, the thickness of the circular filter also has a corresponding impact on the picture. Thicker filter will increase vignetting, and thinner filter will reduce vignetting.
2. Square filter: usually used with lens filter bracket. The lens filter bracket is fixed in front of the lens, and the square filter can be used by inserting it into the lens filter bracket. The advantage is that it can be applied to various types of lenses, and the commonly used sizes are 3×3 and 4×4. This type of filter is widely used in landscape photography.
3. Rectangular filter: Use the same method as the square filter. Unlike square filters, they have more room to move up and down. The most commonly used size is 4×6.
The above are several common filter types, and the following will explain four common filters in detail.
Ultraviolet color filter
There is no most commonly used filter, and each lens should be equipped with a lens filter. The ultraviolet filter is transparent. The film era was used to reduce the exposure of ultraviolet rays to film, and now it is mainly used to protect your lens. The price of UV filter is usually very cheap, even if it is damaged, it will not hurt. There are some "powerful" ultraviolet filters, which can effectively reduce the smog in the atmosphere and reduce the purple edge in photos.
PL polarizer
There are two kinds of polarizers, also known as polarizers: one is CPL circular polarizer and the other is LPL linear polarizer. SLR cameras do not use LPL, because it will lead to metering errors; We often use CPL, and the main function of polarizer is to reduce the polarized light reaching the camera lens. This can reduce the reflection of non-metallic surfaces. If we take pictures of water, the effect of using polarizer is very good, because it enhances the details of water. When shooting the sky, you can enhance the color of the sky to make it bluer, and at the same time enhance the white of the cloud and improve the contrast. It can also reduce the atmospheric smog and let us get clearer and sharper images when shooting outdoors.
Neutral density filter
When the light is very strong, we will use a neutral density filter, which is like putting a pair of sunglasses on the lens, which will reduce the light entering the lens. By reducing the intensity of incident light, we can shoot at a slower shutter speed without producing overexposed images. In this case, if we plan to shoot moving objects such as flowing water, ND filter combined with tripod can produce smooth effect.
Graded neutral density (GND) filter
The lens of the filter has a gradual change from dark to light, that is, the top color is dark and the bottom becomes transparent. In other words, when shooting the sky, the sky is usually very bright and the scenery is dark. This is the use of GND filter, which can keep the exposure of the picture consistent. They are usually square or rectangular, and filter holders are required for use. This filter is suitable for shooting before sunrise or sunset.