Basic knowledge of photography

Basic knowledge of photography. In life, many people like to take pictures with cameras, and they have certain skills and methods when taking pictures. Many people don't even understand the basic knowledge of photography. Let me take a look at the relevant information of the basic knowledge of photography with you.

Basic knowledge of photography 1 1, exposure

Exposure in photography simply refers to the process that light enters the camera and leaves an image on the photosensitive element inside the camera. The size of the aperture and the speed of the shutter determine the exposure, while ISO determines the exposure speed of the camera. According to the intensity of light entering the camera, photographic exposure is usually divided into normal exposure, underexposure and overexposure.

Second, measurement.

In order to get accurate exposure, it is necessary to measure light when shooting. Photometry in photography is realized by the camera's built-in photometry system and external exposure meter. Because the external exposure meter is rarely used, the metering mentioned now is mainly aimed at the built-in metering system of the camera.

What is photometry? To put it simply, the camera measures the light of the scene through the photometric system, obtains a correct exposure value, and then sets the appropriate aperture and shutter according to this exposure value. This process of measuring exposure value is called photometry. Taking Canon as an example, the built-in metering system of the camera can be divided into evaluation metering, partial metering, spot metering and central metering.

Third, focus.

Focusing is one of the important links in shooting. When shooting, if the focus is not accurate, the picture will be blurred, even after the later period, it is irreparable. Camera focusing is divided into automatic focusing and manual focusing.

Usually, when we shoot with the shutter half pressed, we often hear a beep, which is a hint of successful focusing through the camera's autofocus function. Auto-focus is divided into single auto-focus, continuous auto-focus and intelligent auto-focus according to the number of focusing times during shooting.

According to the focus range, it can be divided into single-point autofocus, local autofocus and multi-point autofocus.

Four, aperture, shutter, ISO

The aperture shutter ISO can be said to be the most important thing in photography. All the shooting is realized around these three changes. Because the knowledge of the three is relatively large, I won't talk about them one by one here, but only explain their respective functions, so that beginners can have a general understanding and lay the foundation for subsequent learning. The so-called aperture is a large or small round hole composed of a group of small iron sheets on the lens.

It is used to control the amount of light entering the camera. The shutter is equivalent to the curtain on the window in the camera, which is used to control the time when light enters the camera. ISO is equivalent to the light sensor in the camera, and its function is to improve the brightness of the picture. The biggest problem with ISO is that the higher the value, the more noise there is in the picture. Therefore, it is mainly to adjust the aperture and shutter when shooting. The faster the shutter, the shorter the time for light to enter the camera, and vice versa. The larger the aperture, the more light the camera enters, and vice versa.

Verb (abbreviation for verb) safety shutter

This is mainly for hand-held shooting at ordinary times. The so-called safety shutter refers to the lowest shutter speed that will not blur the shooting because of slight hand jitter when shooting with hands. The safety shutter is closely related to the focal length of the lens used. Usually, the value of the safety shutter is the reciprocal of the focal length of the lens used when shooting. For example, if the focal length of the lens used for shooting is 85mm, then its safety shutter is 1/85 seconds. For some inconspicuous focal length marks, the safe shutter speed should not be lower than 1/30 seconds.

Sixth, depth of field

Depth of field is mainly for aperture. When shooting with a large aperture, the clear range of the picture background is relatively small and the blur is serious. When shooting with a small aperture, the clear range of the picture background is relatively large. In photography, the clear distance is usually called the depth of field, like taking a picture with a large aperture and a small clear distance, which is called the large depth of field (shallow depth of field).

Novices often mistake the aperture size for the depth of field because they don't know the depth of field. Here is a relatively simple and feasible method, that is, when looking at the depth of field of a picture, you can look at the aperture value upside down, and you can easily distinguish the depth of field, such as F4 and F20. When the values are reversed, it becomes 1/4 and 1/20, and 1/4 is more important than 1/20.

Seven, the focal plane

This symbol on the camera is the focal plane, which is mainly used for focusing. For the sake of understanding, the focal plane can be imagined as a plane. When shooting, if there are multiple subjects, try to keep them in the same plane, so as to ensure that multiple subjects in the same picture can be shot clearly. Here are two contrast pictures, which are easier to understand at first glance.

Same plane (focal plane)

The seven basic knowledge of photography will help beginners to know their cameras faster. Seven knowledge points, each of which is rich in content. I hope beginners can use this article as a starting point for learning photography.

Basic knowledge of photography 2 First, understand the camera.

There are many buttons on our camera, so we need to know their purpose in advance. For the sake of later, I don't know where the button is when I need to adjust the parameters!

Therefore, we should know our own camera, which is our weapon. It is recommended to take the camera and follow the instructions carefully!

Second, exposure and exposure three elements

Three elements of exposure: aperture, shutter speed and sensitivity ISO.

1, exposure

Exposure is simply the brightness of our picture. We compared the correct exposure of a glass of water:

When the water is less than one cup, the brightness of the picture is not enough, so it is called underexposure, also known as underexposure.

When there is more than one cup of water, the exposure brightness is too bright, so it is called overexposure, also called overexposure.

2. Hole

Aperture is the aperture size of light entering the camera, just like the aperture size of a water pipe. The larger the aperture of the water pipe, the more water is produced per unit time, so the larger the aperture, the more light, so the more exposure, the brighter the picture. At the same time, the aperture size has a great influence on the depth of field, that is, it has a great influence on the blur and clarity of the background.

The larger the aperture (the smaller the value), the larger the entrance aperture and the more light. Therefore, the greater the exposure, the higher the brightness of the picture, the shallower the depth of field and the higher the degree of background blur.

The smaller the aperture (the larger the numerical value), the smaller the entrance aperture and the less the amount of light entering, so the smaller the exposure, the darker the brightness of the picture, the greater the depth of field and the higher the background definition (the clearer the background).

3. Shutter speed

Shutter speed refers to the length of time that light enters the camera, and it refers to the time from opening to closing of the shutter.

It's like the length of time a water pipe has been drained. The longer the time, the more water.

The faster the shutter speed, the shorter the light input time, the less light input, the smaller the exposure and the darker the picture.

The slower the shutter time, the longer the light input time, the more light input, the greater the exposure and the brighter the picture.

High-speed shutter can capture moving objects and freeze the wonderful moments of motion.

The slow shutter can smooth the fog of the waterfall, shoot the light painting of the car tracks and create different beauty.

4. Sensitivity ISO

Sensitivity is the sensitivity of photosensitive elements to light.

Under the same brightness of light, the higher the sensitivity, the more sensitive the photosensitive element is to light, and the brighter the picture will be.

High sensitivity will produce noise, so it is generally recommended to use it with caution.

Third, white balance.

The color temperature has to be mentioned in the white balance, which is related to whether it is cold or warm.

Simply put, it is the setting of color temperature K value in the camera. I won't discuss the theory here, otherwise the article will be too complicated.

Generally, the median value of k is calculated based on 5000:

When we want the picture to be blue and cool, we will lower the k value to 5000.

When we want the picture to be yellow and warm, adjust the K value to above 5000.

Fourth, exposure compensation.

Exposure compensation is the effect of increasing light or reducing light on the brightness of the picture after photometry. This function is set to prevent ray measurement from failing in some cases. There is a principle of "adding white and reducing black", but today we won't talk about this principle. Please remember:

If the picture is dark after shooting, you can adjust the exposure compensation to the positive direction to increase the exposure;

If the picture is bright after shooting, you can adjust the exposure compensation to the negative direction to reduce the exposure.

V. Measurement and measurement methods

Photometry is a process in which our camera measures the light in the picture.

Measurement methods mainly include evaluation measurement (average measurement), central key average measurement and field measurement.

1, evaluation photometry (average photometry)

That is, the camera divides the picture into small squares, measures the light of each small square separately, and then statistically averages it to get the final exposure. It's troublesome to say, but it's actually a very short process. It is a very useful photometric method, but it is not practical for large light ratio scenes.

2. Center key average photometry

This metering mode is to average metering in the middle area of the camera, not the whole picture, but the most practical metering mode, because most of our cameras rely on the middle area of the picture to meter light, which is also the most widely used.

Step 3 spot metering

Spot metering is the most accurate metering method, which can ensure the most accurate metering of our subjects.

I have to mention the linkage of measuring points here. Nikon cameras basically have this function, only a few other cameras do. Point-to-point linkage means that focusing and photometry are the same, which can ensure the focus and photometry of the subject well, because our subject sometimes doesn't have to be in the middle.

Six, focus and focus mode

Focusing is the process of making our subjects shoot clearly.

1, manual focusing

By manually adjusting the zoom ring to adjust the sharpness of the subject, it is generally used when autofocus cannot meet the needs. After all, manual adjustment is a waste of time.

2. Single autofocus

Focus on the subject at one time, suitable for shooting still life.

3, continuous autofocus

After half pressing the shutter, the object will continue to focus and move. Keeping the shutter half pressed can make the focus follow the moving object, which is suitable for shooting moving objects.

4. Fully automatic focusing

Use the camera to automatically determine the focus and automatically switch between single autofocus and continuous focus, depending on whether the subject is moving or not.

After understanding these six points, you can get started easily. Welcome to the world of photography!

Basic knowledge of photography 3 Step 1: What is the aperture?

It is easy to understand what an aperture is. We can think of it as the pupil in our eyes. The bigger the pupil, the more light enters the eye.

Aperture size, shutter speed and ISO together produce exposure. The change of aperture size will also affect how much light enters the sensor.

What effect can be found by different aperture sizes will be introduced in detail later. Simply put, a large aperture allows more light to enter the sensor, and a small aperture allows less light to enter the sensor.

Step 2: Aperture value

The size of the aperture is usually expressed by the aperture series. On your camera, you will see "f/" followed by a number. This number represents the width of the aperture. The size of the aperture will ultimately affect the exposure and depth of field of the image.

Many beginners are puzzled that the smaller the number after "f/", the larger the aperture. Why is this? The answer is simple, but you have to know what aperture values there are first.

As follows: f/ 1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/1,f/ 16, f/22.

Then we need to focus on what the number after "f/" means. Every time the number increases by one step, the aperture size will be reduced by half, which means that the amount of light entering the camera will be reduced by 50%.

We can draw the above conclusion through calculation. For example, suppose you have a 50mm lens with an aperture of f/2. To get the diameter of the aperture, that is, the focal length/aperture size, divide 50 by 2, and the diameter is 25mm. Then take the radius, that is, divide it by 2, and then multiply the square of the radius by pi to get the area of the aperture. The whole equation is: area =r * π.

Look at the following example, the focal length is 50mm:

F/2:50 mm /2 = 25 mm aperture. Its radius is 12.5mm. Using the above formula (π * 12.5mm), we get an aperture area of 490 mm ..

F/2.8: 50 mm/2.8 = 17.9 mm aperture diameter. Its radius is 8.95mm. Using the above formula (π*8.95mm), we get an area of 251.6mm..

Now, according to rounding, the aperture area of f/2 is about 500, and that of f/2.8 is about 250. According to the above, the larger the aperture, the more light enters. Therefore, if the aperture of f/2 is not the aperture of f/2.8, if the numerical value is increased by one step, the aperture size of the aperture will be reduced by half.

Of course, we have to calculate the aperture area every time, and then adjust the aperture value, which is very complicated in shooting. Here's a simple way for us to quickly compare aperture sizes.

We can regard the "f" in "f/2" as "1", then we can convert "f/2" into the number 1/2. "f/4" can be expressed as 1/4. This is a good contrast. Obviously, 1/2 is obviously greater than 1/4. So the aperture of "f/2" is larger than that of "f/4".

Step 3: How does aperture affect exposure?

Aperture is one of the three elements of exposure, and the other two are shutter speed and ISO, which means that they will determine whether your exposure is correct or not. In order to understand how the aperture affects the exposure, we need to do an experiment, keep the shutter speed and ISO constant, and only change the aperture size, so that we can see how the aperture affects the exposure.

In the following photo, the ISO is 200 and the shutter speed is 1/400 seconds, which remains unchanged. Change the aperture size in turn: f/2, f/2.8, f/4, f/5.6, f/8, f/1,f/1,f/22. The results are as follows:

The results show that the larger the aperture value (small aperture), the smaller the aperture value (large aperture) and the larger the exposure. However, aperture changing exposure is not its only function, another function is to change the depth of field effect.

Step 4: How does the aperture affect the depth of field?

Depth of field is a big topic. Generally speaking, the depth of field is whether the foreground and background of the subject are clear. Let's take the background depth of field as an example: depth of field is usually divided into shallow depth of field and deep depth of field. The depth of the scene means that the back of the subject is blurred, while the depth of the scene is just the opposite, and the back of the subject is clear.

When shooting in aperture priority mode, we can manually control the aperture size, and other variables will be automatically controlled by the camera (Auto ISO), and the focal length will remain unchanged. In this way, we can do an experiment to see what the influence of aperture on depth of field is; The following photos are arranged in this order: f/2, f/2.8, f/4, f/5.6, f/8, f/1,f/ 16, f/22. Note that the depth of field increases every time the aperture decreases.

Well, from the above experiment, we can draw a conclusion: the larger the aperture (the smaller the value), the shallower the depth of field (the blur); The smaller the aperture (larger the value), the deeper the depth of field (clearer).

Step 5: What's the use of different apertures?

First of all, the choice of aperture is irregular. This largely depends on the artistic effect and shooting environment you want.

The following are some basic usages, which can only be used as a reference for us to use the aperture.

F/1.4-Very useful in low light conditions. It also has a very large shallow depth of field effect. Suitable for shooting with lens effect. F/2- This range has many similar uses, but the price of f/2 lens is one third cheaper than that of f/ 1.4 lens. F/2.8—— It is still effective in low light conditions, but it can keep the face clear due to the deeper depth of field, and is suitable for shooting people. The aperture of most good zoom lenses is 2.8. F/4- The maximum aperture of some landscape photos is f/4. When shooting people, although the aperture is not very large, the long focal length can still shoot a good shallow depth of field. F/5.6-It is suitable for taking photos of two or three people, but it is not good in the case of insufficient light. F/8-Suitable for taking big photos, because the F/8 aperture can make people in the front and rear rows clear. F/11-Usually, this is the clearest place for your lens. Suitable for portrait shooting and scenery. F/ 16- When shooting in clear weather, you can consider using this value f/22- the best scene setting, which can show more foreground details.