Do you really understand these photo parameters?

When we take pictures, we will inevitably hear words such as aperture, focal length, shutter and depth of field. At first, I was confused by these words. I didn't know what it was, and of course I couldn't adjust the parameters.

When most people first started shooting a SLR, they definitely used the automatic file the most, but it is difficult to shoot a good film with the automatic file, which is why many people think that the SLR is useless as soon as they see their own films. The source of this feeling. If you want to make a good movie, you must learn to use parameters skillfully to achieve the desired effect.

What is the aperture?

Aperture is a parameter used to control how much light enters the photosensitive element of the fuselage. Aperture is generally expressed by f value, which is equal to the focal length of the lens/the diameter of the blade in the lens when shooting.

What do you think of the size of the aperture?

Many people like the background blur effect of large aperture, but the aperture is not the bigger the number, but the opposite. We can often see different aperture parameters, such as f/ 1.8, f/2.8, f/4.0, f/22, etc. In this case, f/ 1.8 is the largest and f/22 is the smallest. Generally, the fixed-focus lens can make the aperture very large, such as the aperture of Leica's night eye f/0.98. For the zoom head, f/2.8 is already a large aperture.

Is the aperture bigger, the better?

No, we need to determine the appropriate aperture according to different shooting needs. For example, to shoot the Starlight Glimmer effect of street lamps at night, you need a small aperture; When shooting portraits and still life, you need to blur the background, so you need to use a large aperture.

02 focal length

What is the focal length?

The word focal length is familiar to everyone. We all studied physics in middle school. Focal length = object distance/image distance, but in photography, focal length roughly refers to the distance from the center of the lens to the photosensitive element that can clearly image.

There are so many lenses with different focal lengths on the market, is there a difference?

Of course there is a difference.

The lenses on the market are divided into zoom lenses and fixed-focus lenses. A zoom lens is a lens that can be optically zoomed. In layman's terms, it can enlarge the distant scene. For example, Canon's 18- 135mm f/4, 18-200 f/4 and 70-200mmm f/2.8 are all zoom lenses. Fixed-focus lens refers to a lens that has only one focal length and cannot be optically zoomed. For example, Canon 50mm f/ 1.4 is a fixed-focus lens.

How to choose the focal length?

1. scenery

When taking landscape photos, we hope to have a wider perspective and better reflect the spectacular feeling of the landscape, so at this time we need a lens with a focal length of 8mm-35mm, and the lens with a focal length within this focal length is collectively called a wide-angle lens. For example, Canon 16-35mm f/2.8 and17-40mmm f/4 are all wide-angle lenses.

2. Portraits and Still Life

This kind of photos should be the most photographed type in daily life. When shooting portraits, we usually choose a lens with a focal length of 50mm-100 mm. One of the most commonly used lenses for shooting portraits and still life is the 50 mm fixed focus lens. Because the scene we see from the focal length of 50mm is very similar to the scene seen from the normal perspective of human eyes, the photos taken in this way will be very harmonious. Of course, when taking full-length photos of some people, we can also choose some slightly wide-angle focal segments and put the position of the people at the lower position of the photo, which can skillfully lengthen the long legs.

3. Fax and telegram

When shooting distant objects, such as a bird on the other side of the river, we can't go in and shoot at this time. At this time, we need a lens with a focal length greater than 100 mm, which can enlarge the distant scene, so it is very suitable for shooting this kind of scene. Moreover, this kind of focal segment brings the distant scene very close, so the viewing angle is narrow, which is conducive to the simplification of the background.

Shutter refers to the exposure time when shooting, that is, the time when the aperture blade is opened and the light shines on the photosensitive element. The unit of shutter is "seconds", and the common shutter speeds are 1, 1/2, 1/4, 1/8,115, 1/30.

Generally, a long shutter time needs to be used with a tripod, which is often used for shooting scenes with poor light, such as night scenes and long-time exposure shooting of star tracks. Generally speaking, when shooting a still life or portrait by hand, the shutter time should not be longer than 1/25 seconds. This time is called "safety shutter". When the shutter speed is above the safe shutter speed, the clarity of hand-held shooting can be basically maintained, while at the safe shutter speed, the picture is likely to be blurred because of instability.

In the movie era, we bought films with different sensitivities, but now we can adjust the sensitivity in the camera to meet our various shooting needs, such as choosing ISO200 to shoot on cloudy days, choosing ISO400 to shoot at concerts and so on. In the case of poor lighting conditions, you can reduce the high sensitivity and use a faster shutter speed to avoid blurring caused by hand shaking. However, the higher the sensitivity, the more noise there is in the picture. For example, taking pictures with your mobile phone at night will make the picture full of noise.

I hope you can learn something from this article. If you have any questions or suggestions, please tell me in the comments. See you next time ~

Text/deer

Photo/selfie, Baidu

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