Usage and skills of aperture
Want to shoot high-quality and creative pictures. Mastering the use of aperture is one of the important factors, so that the audience can really feel a good sense of space art from the photos.
The aperture principle is equivalent to the iris of the human eye. The larger the aperture, the more light passes through; On the contrary, the smaller the aperture, the less light will enter. All aperture values are calculated according to this law, and the light input of each aperture level is half of the previous aperture value. We can use f / 2.8 or F2 8 to represent the aperture value in this form, the aperture range involved in shooting is generally F2 8～F32。 The aperture value is a ratio (fraction) expressed in the form of 1:2.8 or 1:5.6. The initial value of aperture numerical calculation is 1: (20 × 21 / 2), the next aperture value is 1: (21 × 21 / 2), and so on, the order is 1: (2n-1) × 21/2） 。
If you think the aperture of the camera is only used to control the exposure, you really should have a good understanding of one of the most important skills in photography, that is, the size of the aperture will directly affect the depth of field of the subject, or the background is completely visible; Or the depth of field is very shallow, so that there are fuzzy parts on the photo, so that the photo has a three-dimensional feeling.
F2. 8 suitable for model and portrait photography
During model photography, almost all the characters will leave shadows due to lighting. If the direct sunlight is too strong, the shadow will be very obvious. In order to keep the shutter speed of the camera in a suitable range, professional photographers basically only use at least F2 Large aperture with high light input above 8. With such a large aperture, light is usually enough.
In addition, the large aperture can also achieve the second purpose, which is to make the depth of field very shallow, so that the focus of the photos can be focused on the characters to be photographed, and the background will become blurred. In a monocular camera, this effect can be directly observed through the viewing window of the camera. At the same time, in order to make the photos brighter, it is also necessary to control the aperture of the lens within the range of large values. In this way, when you press the shutter, the camera can take the desired picture with the preset aperture value.
However, only a large aperture can not make the background in every photo blurred enough. This is because as long as the focal length is close to infinity (which is represented by "∞" on the camera), all objects that can be seen at infinity in the photo will be clearly displayed in the photo. Therefore, when shooting models, photographers need to keep a long distance from models. In addition, in order to achieve the effect of large aperture, you also need to use a telephoto lens. Usually, in model photography, it is necessary to use an ultra long focal length of more than 300mm.
In portrait photography, it is also necessary to distinguish the subject from the background. However, in this case, a focal length of about 85 mm is sufficient. This is because compared with model photography, portrait photography only needs to shoot the head and upper body. Of course, it can also be realized by walking closer to the model.
The method of blurring the background. If you want to get a blurred background, you can use the following two methods. 1. When shooting in sunlight, just shorten the exposure time. For example, by shortening the exposure time from 1 / 60 second to 1 / 125 second, the aperture can be increased by one level, for example, from 1:5.6 to 1:4.
2. If you want to take photos with the flash, you usually need to synchronize the shutter with the flash. However, in order to reduce the light input of the image sensor, a medium gray filter can also be used, which can block some light from entering the image sensor.
Close up: when shooting a portrait, the focal length of about 85mm can blur the background. F5. 6 suitable for people and travel photography
Taking travel photos is not allowed to prepare slowly. You must respond quickly. A medium aperture allows enough space for those eye-catching themes.
It is difficult for us to recommend the aperture for people and travel photos, because there are great differences between the subject matter and the environment. However, we can still tell you a good starting point. Under medium aperture, you can respond according to different light conditions, reduce or increase the aperture. The "landscape" shooting mode, which can be found in many digital cameras, uses a medium aperture. In order to accurately control the size of the aperture, you should select the "aperture prerequisite" (AV) mode, or simply use the manual mode to adjust.
During travel, tourists often take pictures of scenery, houses or urban features. These subjects will attract the audience's attention because of the different brightness in the picture, so the automatic exposure mode in the camera is difficult to bear the burden. In order to obtain the best aperture value, professional photographers usually choose a set of aperture ranges. They first switch to manual mode and then set the aperture to a medium value. Next, press the shutter several times, and then increase or decrease the aperture to repeat shooting. If the photos taken in this way still can not show all the light effects, they can only be post edited in Photoshop. You should arrange the photos in turn, and then use the color mask to modify the underexposed or overexposed parts. When shooting a distant landscape, you can no longer expect a blurred background, especially when shooting the details of the landscape. For news photos taken during the trip, the surrounding audience should also be put into the event. It's best not to have fuzzy places on the picture.
Taking group photos with multiple people also requires depth of field. Portrait mode is inappropriate here, because the automatic function of the camera will open the aperture. At a focal length of 50mm, F5 The aperture of 6 to F8 can fully show the depth of field, so that everyone in the picture can be seen clearly. If you use a longer focal length, you should continue to reduce the aperture or be farther away from the subject, so as to increase the depth of field.