CPL is a filter that photographers generally use. It is used for landscape photography. It eliminates unnecessary polarized light to make the overall picture clearer and more transparent. But how do you use it? How effective will it be? This article will introduce the techniques and applications of using CPL!

 

Examples of using CPL are:

  1. For landscape photography, it can highlight the layers of blue sky and white clouds.
  2. Eliminates reflections on water surface.
  3. Eliminate stray light from snow.
  4. Increase color saturation.
  5. Enhance the effect of blue color.

2.5 sec f/16 18 mm ISO100 using a tripod, anti-shake off* The author uses a polarizer to take a sunset in Gaomei wetland

How to Install and Use the CPL

After purchasing a appropriate sized CPL (need to match the diameter of the lens, such as 77mn, 52mm), you attach it to the lens. Please note that CPL is different from other filters. CPL contains two rotating lenses. So keep in mind that one side of the lens is firmly mounted on the lens, and the other side of the lens can be rotated freely.

When using the CPL filter, we need to use the viewfinder to monitor the picture while rotating the lens in front of the CPL . When the CPL is rotated to an angle you think is appropriate, you can press the shutter to shoot. Please note that if you change the camera from horizontal to straight, you must adjust the CPL again to reach the proper angle.

Tips for using CPL for landscape photography

Many times CPL is used in landscape photography to eliminate unnecessary polarized light/reflections and make the overall picture clear and more transparent. But how can I use CPL to see the effect? Roughly remember the following principles:

  1. Don’t face strong direct light or the sun.
  2. To eliminate the reflection on the water surface, it is best to be at 45 degrees to the water surface. The effect of elimination will be more significant.
  3. Carefully observe the slight change in color saturation in the viewfinder (if you use it for the first time, you can practice with a computer screen. When you rotate it, you will find that the LCD screen will be darkened by light)
  4. When viewing through the viewfinder, remember to turn it counterclockwise to prevent your polarizer from being locked inadequately, and turn the polarizer down while rotating!
  5. To enhance the effect of the blue sky, there is still a general principle. Do not face the light, otherwise the polarizer cannot recover the blue sky you are shooting. Backlit shooting (the sun or the light source is behind your back). To obtain a good blue sky effect, of course, if you want to be a bit stronger, it is good to add a polarizer.

After-Rain Plant Photography is also a good time to use polarizers, because the plants that have been rained on will be covered with raindrops, The result polarization of the light often makes us take green that is not green enough, and the overall feeling is gray. At this time, you can use polarizers to achieve better color saturation reduction, while eliminating water droplets or water film on the leaves. The extra reflection!

0.3 ”f /13.0 40mm ISO100 anti-shake function is opened

When photographing the surface of the sea or the water, you can get a more transparent jellyfish with a polarizer!

1/80 f / 11 30mm ISO 100 anti-shake is turned on

So how to rotate the CPL to achieve the best angle?

Because the front end of the CPL’s grating ring does not have a certain scale, and the substance of the mark is not significant, all the basis must be based on the object you shoot and the angle of the lens to determine where the best position will be.

For example, we want to shoot small things in glass cabinets. When our lens is parallel to the cabinet, the shooting angle is mostly parallel. At this time, no polarizer is used for shooting, usually reflective. The phenomenon will not be too serious and will be slight, but it will also be the most disturbing situation for photographers, because even with the addition of polarizers, the effect of eliminating polarized light has not improved significantly, because the polarized light caused by reflection and the lens In between, it is almost vertical. (Try to imagine that the light will reflect when it encounters the object. If the angle of reflection is close to vertical, then the light will move back and forth between the object and the lens. Even CPL, there is not much polarized light that can be eliminated. The rest All went to the imaging element to image it!)

Then change the shooting position, when using CPL to eliminate polarized light, the effect will be more significant, but how to properly rotate it to a suitable position?

Because there is no scale on the CPL, it is convenient for us to understand where the grating angle of the CPL is and which angle of polarization is suitable for use (* Even if it is marked, the effect is not great, because we cannot see the light actually enter The path and angle of the lens) So after the CPL is installed, we must carefully observe whether the originally reflected light in the viewfinder rotates the polarizer slowly “abruptly disappears” at a certain angle. In addition to more practice,  the main technique is when rotating do not worry, slowly observe the changes in the viewfinder.

Use points: Where the reflective part turns from bright to dark, the best angle to eliminate the reflective light!

Since the CPL and the viewfinder are mentioned, the author provides a convenient and easy-to-use secret here:

Nowadays, due to the rapid development of optical technology and electronic technology, many monocular cameras already have the second option outside the traditional viewing window, which is instant preview. The LCD screen is used for framing and composition. Of course, it is called real-time preview. The change is also close to the instant change. The same reason, after we install the polarizer, we use the rotation of the polarizer to eliminate the effect of polarized light. It can also get the correct angle without effort due to the large screen of the LCD. In addition, because the exposure compensation of the instant preview can also adjust the shooting parameters to the optimal exposure value, so that the overall picture shows the ideal exposure distribution, so that the adjustment of the CPL can be presented more clearly and more clearly. This is the optical view The large picture and bright feeling that the viewfinder cannot provide! After all, the eyes are very faithful to use the CPL to dim the light into the light, this … Should it be good or bad?

Generally, CPL is composed of two optical lenses and a polarizing film, and the rotating ring on the front almost does not indicate the polarization direction.

Watch for Shutter Speed

Finally, I want to remind everyone that after using a polarizer, the overall amount of light will decrease , so the exposure time will also increase relatively. If you are shooting in a dim or dark place, remember to control the shutter time to avoid all the photos taken out!

Note 1: Due to the relationship between the mirror coating of the polarizer, some polarized light will cause interference and strengthen blue light.

 

Author: Neo Lin