Basic knowledge of photography

Instant exposure leaves a variety of images, and a square inch can contain thousands of words. It is the beautiful wish of many alumni to use the camera in their hands to capture beautiful moments and leave unforgettable memories.

For this reason, some friends have tasted a lot of the joys and sorrows of failure and success. But for more friends, photography still seems to be very mysterious, elusive but out of reach.

A successful photograph requires the perfect combination of photography technology and art. The photographer should be a "miscellaneous person".

In this section, I will introduce some knowledge about photography to my friends. If friends encounter problems during photography, you can write to us and we will answer them in a targeted manner.

How are the images in photos produced?

Anyone who has taken photos knows that the birth of a perfect photo requires a complex process.

The image formation process can be represented by the following figure:

1. Shooting exposure

First of all, the photographer must capture the picturesque scenery through the lens of the camera , colorful scenery is recorded on the film built in the camera. This step is commonly referred to as exposure, and it is an indispensable part of the entire photography process. At this time, there is an invisible image on the film called a "latent image". As the name suggests, it is a "latent image."

2. Development of negative film

The film that has been shot must be processed to turn the potential image into a visible image. The work of developing film can be done by a professional processing and expansion shop, or you can do it yourself. If you use color negative film, after the development, bleaching, fixing and other processes, you can see that there is an image on the film that is opposite in light and dark to the original scene and has complementary colors. Usually, we call this image a "negative image". Film with a negative image is called a "negative".

Here to remind friends:

Film is a special recording material that is different from the various papers used by painters and writers. This material cannot be opened in a bright room before it has been processed, and no image can be seen when it is opened. Moreover, if you open the cassette at this time, your early shooting results will be ruined!

Don’t underestimate the small negatives. Only if the quality is good can the images in the photos be good. After developing the film, be sure to keep it clean to prevent it from being stained with dirt and scratches. Therefore, when the wet film is drying, it should be cooled in a clean environment. Dust should not be allowed to stick to the film, and the film should not be rubbed casually with hands or a rag. This can easily leave fingerprints or scratches on the film. Rinse Good negatives should not be exposed and should be stored in special negative bags to avoid dust. Because once there are scratches on the film, dark stripes will be left on the photo. If there is dirt on the film, a corresponding white image will be left on the photo.

3. Print or enlarge

Seeing the negative image is not the ultimate goal of photography. If you want to see the image with the same light and shade and color as the original scene, you need to pass the enlargement machine. A lens is used to enlarge the negative image on the small negative to the desired size, and the exposure is printed on color photographic paper. When zooming in, the picture can be cropped, the color can be corrected, multiple copies can be made, and the pictures can be copied to different sizes. After printing, what is left on the photographic paper is also a "latent image" invisible to the naked eye.

4. Development of photographic paper

The methods of developing photographic paper and negative film are basically similar, but not exactly the same. After development, a color image with the same brightness and color as the original scene will appear on the photographic paper.

The photography process involves many specific technical issues. Such as grasping the shooting conditions, controlling the development conditions, etc., each link cannot be ignored, because they will affect the quality of the picture.

Camera use and maintenance

Cameras are high-precision equipment that are durable and reliable. If you operate it correctly and take care of it properly, your camera will serve you well. However, if you don't treat it well, it can often put you in a very awkward position.

Therefore, when using a camera, take care of your camera as you would your own eyes.

I hope friends will pay attention to the following precautions:

1. Do not try to open the lens cover of a fully automatic camera with your hands. The lens cover will automatically open only when the switch is on, and will automatically close when the switch is off.

2. If the camera has a date display mode, do not remove the battery until it is exhausted, because the date function requires battery power to maintain continuity.

3. Fully automatic cameras should use film with DX codes. When purchasing film, make sure there is a DX code mark on the cassette. If film without a DX code is loaded, the sensitivity will automatically be set at a certain value regardless of the film's true sensitivity, which may cause incorrect exposure.

4. When using and carrying the camera, be very careful not to drop or smash the camera, or to avoid strong vibration, impact or squeezing. When carrying the camera on a motorcycle, car, boat, airplane, etc., it should be protected with a thick pad. When using a tripod, be sure to stand it firmly, especially to prevent the tripod from being kicked over or blown over by strong winds.

5. Avoid placing the camera in a closet with sanitary balls or in a laboratory containing chemicals that can seriously damage the camera. Should be stored in a cool, dry and well-ventilated place. Never use solvents such as paint thinner, alcohol or benzene to clean the camera.

6. If the camera is brought from a low-temperature outdoors to a warm room, the moisture will condense into water droplets inside and outside the camera. When taking your camera into a warm room, place the camera in a box or plastic bag to allow the camera's temperature to gradually change. After the temperature difference decreases, open the bag again.

7. Generally, the normal operating temperature range of cameras is 40°C - -10°C. Care should be taken to avoid leaving the camera in a high temperature and high humidity environment for a long time, such as in a car in summer.

8. Dirt, soil, dust, moisture, harmful gases or salt water that penetrate into the camera will damage the camera and prevent it from operating. At the beach, protect the camera from contact with salty, humid air, and prevent it from being splashed with any liquid or rainwater. When the camera is exposed to rain or moisture, wipe off the water and let it dry.

9. When replacing batteries, all old batteries should be replaced at the same time. Batteries of different brands, types, and brands should not be mixed, or new and old batteries mixed. Do not damage or charge the battery, and do not place the battery on a fire, as this may cause battery leakage, self-heating, explosion, etc. The battery should be installed according to the positive and negative polarity indicated.

10. Never try to disassemble the camera.

Because the quality of the lens has a great impact on the image quality, it is also one of the most delicate parts. So its use and protection are even more important.

First of all, keep the lens clean.

When you hang the camera around your neck, the lens must be equipped with a lens cap or a transparent UV lens to protect the lens from being contaminated by dust, oil or other debris, and to prevent it from becoming damaged. Be careful to leave fingerprints on the lens. Do not stack the lens with other items without covering it, do not touch the lens with your hands, or let hard objects come into contact with the lens, and do not develop the habit of leaving it around. Because the lens is dirty, the image quality will be reduced. For example, images shot with a dusty lens will appear low-contrast and blurry. If there are fingerprints on the lens, they will be faithfully reflected on the printed photos. In your photography bag, you should have a lens brush, an air blower (also called an ear cleaning ball), lens paper, etc. If you find that the lens is dirty, use a special lens brush to remove dust and other dry substances, while oil, Fingerprints need to be wiped with special cleaning agent and special soft cloth. Never use hard objects to scrape, as this will not only fail to clean the lens, but will cause greater damage to the lens - scratches. The lighter ones will have to be sent for repair, while the more serious ones will be scrapped.

Another thing to note is that lenses are generally made of glass. The axis of the lenses in each lens group and the positions between the lenses are carefully designed and arranged. During the process, pay attention to prevent the lens from being subject to strong vibrations and bumps, so as to avoid the lens glass from breaking or shifting, thus affecting the image quality.

This problem can easily occur when you mount the camera on a tripod, so be careful.

Types and Selection of Cameras

In the photographic equipment market, there are many styles of cameras and accessories available for purchase. For most families, cameras are valuable items. The initial rush to buy a camera may be exciting, but it can also be daunting, especially after the choice turns out to be a wastefully wrong one. Therefore, when buying a camera, I advise friends to decide on a model based on actual needs and economic conditions, and not to blindly purchase a high-end camera with many "excess features".

Although some manufacturers have tried to produce a single camera that can meet all photographic needs, the result is regrettable. No one camera can serve as an ideal boutique to meet all photographic needs. Therefore, either you will limit the photography you do based on the work that the camera you have chosen can handle, or you will purchase several different types of cameras to meet all the needs you may encounter.

There are many types of cameras. According to the size of the frame, cameras can be divided into large cameras (such as landlines used in photo studios, which can be used to shoot loose sheets), medium-sized cameras (such as 120 cameras, used to shoot 6cm′6cm, 6cm′9cm, etc.) and small cameras. Camera (such as 135 camera, used to shoot 24mm′36mm size). According to the viewing method, it can be divided into two categories: coaxial viewing (single lens viewing) and side-axis viewing (the viewfinder is located above or diagonally above the lens). According to the degree of exposure automation, cameras can be divided into manual, semi-automatic and fully automatic (known as "point-and-shoot") cameras.

At present, 135-type cameras are the mainstream models for home cameras. From the experience of using it, the 135 camera is small in size, easy to carry, easy to adjust the view and focus, and the color film used is more convenient for processing and printing. There are many brands of cameras, including medium, high and low-end. You can purchase it according to your own needs.

If it is only used to take commemorative photos or to carry with you for travel, you can purchase a rangefinder 135 camera. This type of camera is available in fully automatic, semi-automatic and manual types, usually with a flash and can be used in darker environments. This kind of camera is relatively simple to operate. If you want to use it for artistic creation, you still need to buy a mid-range or above single-lens reflex camera, but it cannot be a "point-and-shoot" type. There should be manual adjustment devices to artificially control exposure, depth of field, etc. according to creative needs. If possible, you can also use lenses of different focal lengths.

When making a specific choice among many brands, it is recommended that you consider the following factors:

1. What functions does this camera have and whether these functions are exactly what you need? of? The main technical issues of concern include: framing method, working method of the focusing mechanism, focal length metering and exposure mode of the lens, film rolling mode and flash mode, etc.

2. Is it convenient to use?

3. Are there corresponding series of accessories? If there are lenses of different focal lengths that cannot be matched with the camera body, attach appropriate filters so that you can add them when needed.

4. Is the price reasonable?

After deciding to purchase a certain model, you should choose carefully:

1. Appearance inspection: Whether it is a metal casing, a plastic casing, or leather, it should be smooth and without scratches. No marks, no deformation, no signs of wear. The connection between the lens and the body should be solid and tight. The back cover and the fuselage should also fit perfectly. There are no signs of repeated disassembly.

2. Lens inspection. The quality of the lens directly affects the image quality, so pay special attention when selecting. If the lens is detachable, you can take it off. If it is a fixed lens, you can set the shutter speed to B, open the back cover, aim the lens at a bright place, and use transmitted light to check whether there are mold spots or small spots on the lens. Large bubbles, cracks, scratches, etc. Also use reflected light to check the coating from the side for scratches. The camera's aperture blades should be able to be retracted and retracted freely and should be free of rust and oil stains. The feel when adjusting aperture should be smooth and not too astringent.

3. Check the focusing device: When adjusting the focus, the focusing ring should feel a little resistance, but not stiff and even. The image in the viewfinder should be clear and bright. If it is an automatic exposure camera, you should place different distant and near scenes in the center of the viewfinder to see if the automatic focus system is responsive. For manual focusing systems, the infinity scale line on the focus ring should be aligned with the baseline, and when observed in the rangefinder, the image at infinity should completely coincide with the center of the viewfinder. In the viewfinder of a single-lens reflex camera, The split images should be aligned. When focusing on a close object, use a tape measure to measure the distance between the scene and the camera and check whether the scale on the focus ring is accurate.

4. Check the exposure device: Open the back cover and take exposure photos of scenes with different brightness. If it is a fully automatic camera or an automatic exposure camera, you should try the response of the automatic aperture and automatic shutter. For a manual exposure camera, you should Check whether the display data of the light meter changes when the brightness of the scene is different. When exposing with different shutter speeds, listen to whether there is a difference in the shutter opening time.

5. For cameras with flash, check the flash. After confirming that the battery is intact, turn the flash switch to "ON". When the charging indicator lights up, press the shutter and the flash should Flash, try several times in succession, and pay attention to the charging time interval of the flash, which should not be too long.

6. Check the film transport structure and other mechanical devices: a camera that automatically winds the film should be able to automatically roll the film after loading the film and taking the exposure. For manual film feeding cameras, you should feel a certain amount of tension when feeding the film. The counter should work normally and return to zero automatically when the cover is opened.

7. Display screen check: For fully automatic cameras, install the battery and see if there is a display on the screen. Operate according to the instructions and check whether the displayed symbols match the results of the operation.

Finally, I would like to remind my friends that the above selection methods should be approved by the sales staff and should not be done rashly to avoid trouble.

Develop a good habit of holding the camera

First of all, when taking pictures, no matter whether the picture to be taken is horizontal or vertical, the viewfinder frame must be aligned The bottom edge should be parallel to the horizon. Otherwise, the houses, trees, and people will look like they are about to fall down.

Normal building (picture), rickety pavilion (picture)

In addition, when shooting with a camera, you need to hold the camera with both hands. For example, holding the camera horizontally, usually with the left hand Hold the camera with your heart, adjust the focus with your left thumb and index finger, and press the shutter with your right index finger. Try to keep the camera as still as possible. When pressing the shutter, hold your breath and move gently. If you use too much force, the camera may be vibrated and the image recorded on the film may be blurred. You can clamp your elbows to your body, or place the camera on a solid and stable object, such as a tripod, on your knees, or lean on a pillar or wall. Especially when using a slow shutter speed, it is best to find a support point. , otherwise, it is difficult to obtain clear results.

When using a tripod, do not be careless. After placing a camera on a portable tripod, it is often top-heavy and may fall over when the wind blows; it may be tripped when people walk by. Therefore, one should never leave the camera. Pay attention to the fact that the image will be unclear if there is a relatively large vibration from a vehicle passing near the tripod.

Besides, don’t hold the zoom head with your hands, because the lens has to move back and forth when zooming!

Do not touch the lens, autofocus window, sensor window, flash, etc. with your fingers, hair, camera strap, etc., nor block them in front of these parts, because this will cause a certain part of the photo to be blocked. The inability to record images will also dirty the lens, thus affecting the clarity of the images in the photos.

The camera lens is blocked - photo diagram

Pay attention to the adaptability of the human eye in the photography process

Instant exposure leaves a variety of postures, and a square inch can accommodate thousands of words language.

Almost everyone hopes to capture every beautiful moment with the camera in their hand. However, some friends may have noticed that in some situations, the light seems to be very bright to us, but the captured images are quite dark; some scenes, which appear to be bright and eye-catching to the human eye, are completely unrecognizable when captured on the screen. Why is this?

Everyone who has taken photos knows that picturesque scenery and colorful animals are recorded on photosensitive film after passing through the camera lens. This is purely a physical and chemical process. But our visual experience is not that simple. It is not only the physiological function of the human eye that is at work, but also the influence of memory function and psychological factors. Therefore, the feeling of scenery is not as "objective" as that of film. This characteristic of human vision is called "visual adaptation". Often due to people's "turn a blind eye" to this "visual adaptation", photography errors occur in some cases.

"Visual adaptation" manifests itself in many aspects.

First of all, it shows "comprehensive adaptation of brightness". For example, when people walk indoors from outside, they often feel that the indoor scenery is as bright as the outdoor scenery. However, if you use the same aperture and exposure time to shoot indoor scenes as outdoor shooting, you will find that the indoor photos appear dirty and dark due to insufficient exposure. This is because when a person enters a room, the low illumination in the room will cause the pupil of the human eye to dilate and increase the sensitivity, doubling the amount of light entering the human eye, sometimes up to ten times, making the person unaware of changes in illumination. This is the human eye's "comprehensive adaptation to brightness". Film does not have such an adjustment function. Therefore, from a photography point of view, due to the large adjustment range of the human eye, it is often impossible to correctly estimate the actual intensity of light. This It is detrimental to photography. The solution is to use a light meter to measure the light before pressing the shutter, and make necessary adjustments to the aperture and speed of the camera to compensate for the "brightness adaptation" that the film does not have.

Correspondingly, there is also a phenomenon of "comprehensive adaptation of color vision" to the perception of color, which is manifested in the fact that for different lighting conditions, such as daylight and light, sunny days and cloudy days, morning and dusk, despite the spectral composition of the light source. However, due to the self-adjusting function of the sensitivity of the photoreceptor cells on the human eye's retina, the human eye cannot see much change in the color of the object. In addition, people have memory for the color of the object under white light. Therefore, when When the light source changes, psychological effects make it difficult for people to detect changes in the color of objects. At this time, it is important to remember that film does not have such adaptability. Therefore, different types of film must be selected according to different light sources. , or use a corresponding filter. Otherwise, different color casts will appear.

Another manifestation of visual adaptation is "local brightness adaptation". After staring for a long time, due to the fatigue of the photoreceptor cells in this part of the retina, the sensitivity decreases. When we move our gaze to another light-colored reflective surface, we will be left with a dark "after-image" of the object. . On the contrary, after looking at a black object, when we move our eyes to another light-colored reflective surface, we will be left with a white "afterimage" of the object. As the sensitivity is adjusted again, the afterimage will gradually disappear. If you stare at a colored object for a long time, when your gaze moves to another plane, an "after-image" with the opposite color of the object will be produced. For example, if you stare at a red object, the after-image left by it will The color is almost cyan. This phenomenon is called "local adaptation of color vision", also known as "color afterimage".

The practical significance of understanding this adaptation is that if you stare at one picture for a long time and then observe the next picture, the "after-image" of the previous picture will be superimposed on the next picture. Affects its brightness and color. This can be said to have advantages and disadvantages. Showing complementary colors in the previous image before the second image appears will make the colors in the second image appear more vivid. When color correcting photos, you should try to avoid looking at a picture for a long time to prevent sensitivity loss due to visual fatigue and errors in color judgment.

The third type of visual adaptation is called "lateral adaptation". In color photography, the "lateral adaptation" of vision should also be taken seriously.

In the picture, if adjacent areas have different brightness or color, the sensitivity of the photoreceptor cells in different parts of the human retina will be adjusted, which will cause visual changes. The rule is that bright objects appear brighter on a dark background, and dark objects appear darker on a light background (see Figure 1); the color of the foreground object will change toward the complementary color of the background. See Figures 2, 3, and 4. Figure 1 shows the normal skin color of a human face. Figure 2 shows the skin color of a human face against a red background. It is obvious that the skin color is biased towards cyan, the complementary color of red. In Figure 3, against a blue background, the color of the human face is biased toward blue. The complementary color of color - yellow. Therefore, when taking portraits, you must consciously pay attention to the impact of background color on facial skin color.

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Seying Wuji Qingfeng Seying Hummingbird Photography Network Dipai Image

China Photography Online New Photography China Folk Photography Association Chinese Photographers Association

China Photography Frog Photography Network China Photography Education Network ITNOW-Digital Photography

Sina Photography Landscape Gallery Sohu Travel Channel Public Photography China Photography Market Network

Love Photography Gallery Pconline-Digital Photography Zone China Photography Network Photography Bar

Photography and Videography Third Eye Online Photography Club China Photography Network Canon Group

Tianji Photography Tiandi Classic Photography Huaying.com China Online Photography Network

Electronic version of "China Photography News" Long Photography Beijing Photography Trade Gold Wide Angle Yimaijie

Yi Mountain Photography Online Photo Processing Network Photography Daily Forum China Travel Photography Network

Seyingwuji Picture Forum Qingfeng Forum Dipai Digital Forum China Online Photography Forum

Hummingbird Photography Forum Jianghu Stunning New Photography Forum Photography World

Frog Forum Xici Photography Forum Little Bear Digital Photography Forum Laosha Tea House

China Photographers Association Interactive Community Yijia Forum

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