It is a colored glass disc placed in front of the camera lens to filter the light falling on it, allowing some light waves to pass through and preventing the passage of others. Each filter prevents the passage of any rays except for its color only. For example, the yellow filter allows the passage of red and green and prevents the passage of blue, and the red filter prevents the passage of blue and green rays and allows the passage of red rays only, and so on.
Camera lens filter :
It is made of several materials:
Glass: It is the most expensive and of high quality, but it is breakable.
Plastic and resin: cheap, hard to crumble and good.
Polyester: it is thinner than glass and resin and of very high quality, but it is easily scratched
Polycarbonate: strong, non-scratch, and a suitable alternative to plastic and resin
There are two types of filters:
A- Filters that are directly attached to the lens – Screw-in filters
This type of filter is considered the most widely used as it is installed on a specific lens and becomes part of it and you cannot use it on another lens due to the difference in diameter. The filter size, or rather the diameter of the filter suitable for the lens, can be known through the lens itself, where the number is written in front of the lens or on the side.
B – Filters mounted on the lens – Slot-in filters
This type of filter is installed on the lens through a holder with a diameter suitable for the lens, as you can see in the picture, and the filter is dropped into this holder. The holder usually contains three to four pockets with straps on each side (works like a clothes drawer), which makes it easy for you to put more than one filter at the same time.
One of the disadvantages of this type of filter is that when a wide angle lens is used, the edges of the pockets of this filter appear in the image.
Examples of filters
1- UV filter
This type of filter is transparent, protects from ultraviolet rays and reduces air haze. This filter was used in old cameras that used film to prevent the radiation from affecting the raw film. But now this filter is used to protect the lens from scratches and dust because most DSLR cameras have an internal filter in front of the sensor to block UV and infrared rays. There are some good and strong types of this filter to reduce the blur in the air and also from the purple fringing that sometimes occurs when you take a picture on a sunny
day and the focus is not good, this fringing appears on the side of the image like a ghost.
Caution: It is preferable to buy an excellent type of these filters with “multi-resistant coating” MRC, and they are usually expensive. Because you do not want to install a cheap filter on an excellent lens, if you do that, this filter will not only affect the quality of the image, but will add unimaginable reflections. Desirable, high brightness and image blur.
Tip: If you have a filter and want to know if this filter affects the quality of the image or not. Shoot a scene or anything once with the filter and the second time without the filter. And compare the two images on the camera screen and also in a computer or any other device with a high-quality screen.
2- Polarizing filter
There are two types of this filter, one is linear and the other is circular. Never use a linear filter with DSLRs, especially when the focus is automatic, as it affects the sensor readings.
As for the circular type, it is the appropriate type. It is basically linear, and another layer of glass has been added at the back to correct the path of the light, so that there are no false readings even when the focus was automatic. You can find out the type of filter through the information on the linear box or circular
There are several points to take into consideration:
• There are two effects of this filter when using the higher effect and the lower effect. These two effects depend on how tight (tying) the filter is to the lens, meaning that when it is tight, the other gives you a different result when it is not tight. Of course, the tension is circular, so it is preferable to tighten and loosen each time until you get the desired image
• The highest effect of this filter is related to the sun’s rays when the lens is at a 90 degree angle with the sun in any direction. To simplify, you can make a pistol with your hand and face the sun, then tilt your head right and then left, the ideal point will be where your thumb is in any direction
Avoid using this filter with 20mm . wide-angle lenses Or less, because part of the image will be the sky darker in the case of landscape photography, and it will be difficult for you to modify the image in Photoshop .
Also, the higher effect of this, in some cases, the filter results in an unnatural appearance of the image, as is the case with a very dark sky .
• You may lose two shades of light when using this filter. Note the shutter speed to get the desired image. Or use a Singh Ray brand filter where you will reduce one point of light.
• This filter is thicker than other filters, and therefore it will produce unwanted darkening at the edges of the image, as it is known as vignetting.
3- Neutral Density filter
This filter is used to reduce the light entering the camera for special photo effects. As shown in the picture in front of us, to obtain the milky effect on the waterfall, this filter was used to reduce the degree of incoming light, and thus we can reduce the shutter speed to obtain this effect. See shutter speed by pressing here
There are two types of this filter, the first type is circular (filters that are directly attached to the lens – Screw-in filters) and there are several degrees of opacity. This filter will dim the entire image. As for the second type, as I talked about at the beginning of the article, it is of a type (slot-in filters) and it is called graduated neutral density
This allows you to filter a certain part of the image, especially when there is a high contrast in the scene, especially the sky in landscape cases. .
There are three types of this filter:
• The sharp, meaning that the filter will be a transparent part and a completely obliterated part without a graduated separator between them
Use the filter to reduce the contrast between the brightness of the sky and the ground, as the blurred part of the filter is on the sky and the transparent part is on the ground, by weighing them manually by hand and by looking through the viewing hole or the display screen
Soft as this filter will give you a gradient in the opacity as it is in the image, as it helps you to blend the contrast smoothly, especially when this contrast is not very high, i.e. at sunset
The inverse means that the filter will be darker from bottom to top in the blurred part
Where the middle of the image darkens the area of the sun and remains the brightness of the sky and earth
4- Color balancing /warmin/colling filter
This type of filter changes colors. Specifically, you are alerting the white balance feature of the camera. You can read the topic related to white balance from here. Sometimes the camera options are not enough so you use this type of filter. The 85B filter used in the image adds a warmth to the image, giving a hint of orange.
As for the filter of type 80A, it gives a degree of cold in the form of coolling, which gives a degree of blue color. Generally, this type of filter was used with cameras that use film, but now with digital cameras, you can modify these colors using image-editing programs such as Photoshop.
5- Soft focus filter
This filter reduces the sharpness of the image in a simple way, thanks to its use in close-up photography of people, as it will improve the clarity of the complexion. You can also use it in landscape photography.
6- B&W Filters
There are special filters for black and white photography that block a specific wave of colors and thus increase the beauty of monochrome images, i.e. black and white. There are red filters as shown in the picture and there are yellow, blue, orange and green filters that are also used in monochrome photography.
For example, the red filter blocks the red light and thus enhances the blue light to give the sky color depth and more contrast. As for the green filter, it will darken the color of the sky and illuminate the green color, thus isolating it from the color of the sky. It is preferable to use it in photographing forests and plants.
Some may say the image will be black and white, which will not differentiate the colors. Refer to the picture above. See the red filter. Isolate the white clouds from the blue sky, because the red filter enhances the blue light. As it is known that the image in the camera and the human eye is the reflection of the downlight on the target in our eyes and the downlight consists of colors that the naked eye does not see if you remember the glass prism or simply form a rainbow.
7- Macro filter Close up filter
This circular filter mounts directly to the lens and makes a macro lens. This type of filter, in general, turns your regular lens into a macro lens, but cheaply because this filter makes a small degree of the focal length of the lens. You can see in detail the focal length. It is preferable to use macro lenses instead of this filter.
8- Special Effects Filter
This filter is also circular. It is directly attached to the lens. This filter adds effects to the image such as stars, that is, converting lights into the shape of stars, but these effects can be added using Photoshop.
The filter is your camera’s sunglasses