What are the types of filters in photography?

There are nine kinds of commonly used filters: UV mirror, polarizer, medium gray mirror, medium gray gradient mirror, anti-medium gray gradient mirror, color filter, close-up lens and special effect filter. They are generally made of glass (high-end products), resin and polycarbonate.

The main function of UV mirror is to protect the front lens from being scratched and prevent the coating on the lens from being polluted by dust and water vapor. Most UV mirrors are made of glass, and many photographers like to put them on the lens as protective lenses.

The function of polarizer is to enhance the contrast and blue saturation in the picture, and at the same time offset the glare and reflection in the picture. Adding a polarizer when shooting the sky can get a bluer sky and more contrasting clouds.

When using a polarizer, the angle between the lens and the sun should be 90 degrees as far as possible, and the ultra-wide-angle lens should be avoided, because using a polarizer on the ultra-wide-angle lens will not only cause uneven brightness of the picture, but also easily lead to dark corners.

In addition, the use of polarizer is likely to lose the amount of light entering the two gears.

There is also a GND mirror (medium gray gradient mirror), similar to a neodymium mirror.

This kind of filter is usually square and divided into two parts: one end is a black part like an nd mirror, and the other end is transparent. When the proportion of light in the picture is too large, a GND can save your photo. By metering the two areas, the exposure difference between the sky and the ground can be calculated, and then filters with different gears can be selected according to the calculation results to balance the light ratio of the picture.

GND mirror can also be divided into hard edge and soft edge.

Hard-edge GND is suitable for scenes with obvious dividing lines between light and dark parts in the picture, such as horizon and horizon. However, if there is no clear boundary in the picture, the simple effect of soft edge GND can naturally dim the light in the scene, and there is no unnatural light-dark boundary in the picture.

Finally, there is a special kiND of nd mirror? RGND mirror (reverse medium gray gradient mirror). Similar to ordinary GND mirror, RGND is dark at one end and transparent at the other end, but the darkest color at the dark end is in the middle of the filter and gradually changes to the edge of the filter. If the sun is placed in the middle of the picture when composing, it is difficult for ordinary GND mirror to balance the exposure in the picture, and the reverse gradient mirror can handle this situation well.

Color filters are widely used in the film age, and their main function is to correct the white balance of the picture through the color of the filter. However, in the digital age, few people use filters to correct white balance.

Close-up lens can make ordinary lens have macro shooting ability, which can greatly shorten the closest focusing distance of lens, but at the same time, the image quality will be greatly reduced.

Finally, there are various special effects filters (starlight mirror, soft light mirror, etc. ). Because of the increasingly powerful post-software, such filters are slowly fading out of people's field of vision.