Shulou(Shulou.com)11/24 Report--

There is a small button in the lower right corner of some cameras, the position of the button is relatively hidden, and some camera buttons do not have any words written next to them, so it is easy to be ignored. Look carefully. Do you have any on your camera?

In fact, this button is the "depth of field preview" button, every button on the camera is useful, today we will talk about what the depth of field preview is and under what circumstances this button is used.

01. What is the depth of field when taking photos, you can make the scene (foreground, background) virtual. We can also say that the scene "outside the depth of field" is virtual, and the scene "within the depth of field" is clear. The depth of field is large and small, so the virtual is strong and weak.

02. The aperture can affect the depth of field and large aperture, resulting in a small depth of field, and the photo has a strong virtual effect.

Small aperture, resulting in a large depth of field, the photo weakening effect.

(in addition to the aperture, object distance and focal length also affect the depth of field, which is outside the scope of today's discussion. )

03. Maximum Aperture View Today's digital cameras (especially SLR) often use maximum aperture to view. In other words, the picture you see on the camera when you take a picture is seen through the maximum aperture. If the maximum aperture of my camera lens is F2.8, then when I take the scene, the camera will turn on to the maximum aperture F2.8.

Why use the maximum aperture to set the scene?

Because the maximum aperture also has the largest amount of light, the picture looks brighter and clearer. In order to let you see clearly when taking pictures, the camera often uses the maximum aperture to generate a real-time picture.

At the same time, the maximum aperture is also good for focusing. Some focus only works above a certain aperture, and the focus of a small aperture is not as sensitive as that of a large aperture.

But the aperture can affect the depth of field!

If I don't want too strong virtual effect, I use the aperture parameter of F9.0. But the picture I see at this time is still produced by the F2.8 aperture, and the lens will switch to the F9.0 aperture only when the shutter button is pressed to take a picture.

The virtual image of F2.8 is definitely stronger than that of F9.0, so the real-time preview screen I see is more virtual, and the actual photo taken is weaker.

In order to allow me to see the same depth of field as the actual photo when I preview the scene, the camera adds a "depth of field preview" button. When I press the button, the aperture changes to F9.0, and I can see the depth of field of the actual photo.

As the aperture is reduced, the amount of light input will also be reduced. Some cameras do not have the circuit compensation function, the picture will suddenly dim. You don't have to worry, depth of field preview only allows you to preview "depth of field", does not allow you to preview "exposure", the actual photos will not be dark.

04. The first common function of depth of field preview is to preview depth of field, which is the original intention of developing this function. Especially when shooting some scenes that require high depth of field, it is convenient to see the actual virtual degree of the photo to ensure that the clear place is clear and the blurred place is blurred.

The second common function is to shoot the stars. When shooting a point light source (what is a point light source? The light source is like a "point", not a "big piece"). A small aperture can produce stars, which is very beautiful. The sun at sunrise and sunset, the street lights at night, and photographers all like to photograph the stars.

As mentioned earlier, a small aperture can produce stars. The preview is the maximum aperture, and you can't see the actual star effect of the photo, so you can press the depth-of-field preview button to see the star effect.

This article is from the official account of Wechat: photography Research Society (ID:shoujiPhotography), by Zhang Xiaozhang.

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