Basic course of light for SLR photography

Basic course of light for SLR photography

Illumination direction of light

According to the direction of illumination, light can be divided i

Basic course of light for SLR photography

Basic course of light for SLR photography

Illumination direction of light

According to the direction of illumination, light can be divided into three categories: forward light, backward light and lateral light. Literally, it is easy to understand that even if you don't engage in photography, you will know these kinds of light in your daily life. But it is necessary to understand these kinds of light from the perspective of photography.

Front lighting

Smooth shooting angle

As the name implies, sunlighting is the light in the same direction as the camera shooting, so people and scenery in the picture are illuminated by light, so the photos taken by sunlighting are usually very bright. Usually this is the most comfortable light direction in our daily life. Shun light is also the easiest light direction to shoot, because the objects in the picture are evenly illuminated, so the exposure effect is better controlled, and there are fewer underexposed or overexposed cases.

Side lamp

Side light shooting angle

Side light means that the illumination angle of the light forms a certain angle with the shooting angle of the camera lens, and the light illuminates from the side. Usually side light and lens 60? To 120? The angle between them. Compared with streamer, sidelight creates more contrast between light and shade for the picture, which makes the picture look less dull and more energetic. Side lighting can enhance the outline of the subject, such as a model, and make the face look more three-dimensional. In several light directions, the picture taken by sidelight is rich in layers, the most detailed in content and less difficult to shoot.

Side lights illuminate the Norwegian fjord.

Backlighting

Backlight shooting angle

Backlight is the light whose direction is opposite to the shooting angle of the camera lens, and the light is direct from the front of the lens. The contrast between light and shade is strong and the visual impact of the picture is the strongest. At the same time, backlight shooting can capture the effect of silhouette.

Scenes in a backlit environment

Backlight shooting technology is difficult, especially the accuracy of exposure is difficult to evaluate. Backlight shooting is easy to cause bright background and dark subject because the lens directly faces the light source and the subject is in the position between the light source and the camera. When using backlight to shoot portraits, it is usually necessary to use a reflector to increase the brightness of the model's backlight surface, or directly use a flash to fill the light.

Backlight can produce silhouette effect.

Hardness of light

Maybe you haven't noticed that light is soft and hard. The shooting effect varies greatly with the hardness of light.

subdued light

Soft light is abundant in nature. Soft light has no strong contrast between light and shade, so it is very soft. Soft light can play a icing on the cake when shooting colorful objects. When there is no direct sunlight in the picture, the light is softly scattered, and the light projected on the object at all angles is similar. Therefore, in the case that the light does not have much contrast, it is required that the object to be photographed should have a large contrast, so that the photographed picture can be rich in color and not monotonous.

A portrait taken in soft light

Taking portraits in soft light will be very soft. In the northern hemisphere, choose a house facing north and shoot near the window. At this time, soft scattered light enters the room, and at the same time, soft light with sufficient brightness can be obtained, which is a better way to shoot indoor portraits. Using a soft light cover in front of the flash, or using other things that can cover the light source but let the light out, can also achieve the effect of converting the light source into soft light. This will not leave a hard shadow with very strong edges in the picture.

highlight

At noon in a day, the sun is the strongest, the contrast between light and shade is the strongest and the light is the hardest. The photos taken at noon will have a very strong contrast between light and shade. If you take a portrait, it will leave a very strong shadow on the characters, which will make the contrast between light and shade of the picture strong and the effect is not good.

A portrait taken with strong light in the midday sun.

Many artificial light sources also belong to hard light, such as flashlights. If you shoot directly with a flash, the bright part of the subject will be very bright, and the contrast between light and dark will be strong, leaving a very obvious shadow on the edge of the character.

Types of lamps

natural light

For photographers, natural light is the most accessible light source. Landscape photographers rely entirely on natural light, which is also a very important light source for portrait photographers.

Natural light has many benefits. The audience has a high acceptance of photos taken in natural light, because we live in natural light and are very familiar with and adapted to it. There is no cost to get natural light, and it is very intuitive to use. What you see with your eyes is what you took.

Tulips photographed in natural light.

Although we are familiar with natural light and easy to obtain, we need to have a full understanding of natural light in order to make good use of it to take high-quality photos.

As we know, the earth forms day and night because of its rotation. Seen from the earth, the angle of the sun always changes during the day, from the lowest at sunrise to the highest at noon, then gradually falls back and returns to below the horizon at sunset. So the light varies greatly with the angle of the sun. When the sun angle is low, the light is softer, and at noon when the sun angle is the highest, the light texture is also the hardest.

Because landscape photography can only be shot by natural light, it is necessary to fully understand the influence of light at different times of the day on shooting.

Beginners usually shoot scenery at any time of the day, especially when traveling. But usually the photos taken in this way are mediocre. For experienced photographers, they usually choose to shoot half an hour before or after sunrise or sunset. At this time, the angle of the sun is low, the contrast between light and dark in the picture is rich, and the clouds in the sky will be rendered by sunlight. This time is often called the prime time of photography.

The prime time for landscape photography is after sunrise and before sunset.

However, because the angle of the sun is very low at sunrise or sunset, it is easy to photograph the sun. Even if the sun is close to the horizon, it is still the brightest object. When the sun appears in the camera viewfinder, it is easy to make the backlight of the picture appear dark, so it is necessary to increase the exposure compensation slightly to improve the details of the backlight picture. Don't be afraid that increasing exposure compensation will lead to excessive sun exposure. As long as you shoot the sun, you must be overexposed, so this is normal.

But such a photo with strong contrast between light and dark will also make some details lost. Therefore, you can use HDR shooting method to increase the captured information by taking multiple photos of different exposure value. Usually I take five photos, which are -4EV, -2EV, 0EV, +2EV and +4EV. Such low-exposure photos are used to capture the information in the bright part of the picture, and high-exposure photos are used to capture the information in the dark part of the picture. Then use HDR software to synthesize later, which can contain more detailed photos than single shot. There are many things about HDR shooting, which I will explain in detail in the subsequent tutorial.

For landscape photographers, natural light is especially precious. When you go to a strange place, you may not be familiar with the scenery there and the position of the sun at sunrise and sunset. It doesn't matter. You can find out about it on SunCalc's website. SunCalc intuitively superimposes the sunrise and sunset angles of the sun and other information on the map. As long as you find the destination, you can know when the sun rises and sets, and the angle of the sun at every moment, which is very convenient.

flashlight

Flash is usually prepared for taking portraits. Unlike natural light, a flash can be used whenever necessary.

Nikon external flash

There are many kinds of flashlights with different powers. If you want to use flash, you'd better abandon the overhead flash. This is not only because of the low magnification, but also because the angle is consistent with the lens angle, which makes the picture look monotonous. You can buy an external flash, and it is not recommended to install it on the top of the machine. It is often seen that reporters or wedding photographers will install the flash on the top of the machine. This is because the scene is limited and the subject changes frequently, so they have to do so.

The power of the flash can be adjusted, but although the power is low, the light of the flash is still hard light, which can leave a clear shadow for the subject. So usually the flash needs to be equipped with a soft box to use. Soft boxes come in various shapes and sizes and are used for different shooting purposes. The larger the size of the soft light box, the softer the light. The softened light looks more natural, closer to the feeling of natural light, and the picture looks more comfortable.

The strong light output by the flash directly forms bright light and shadow on the edge of the character.

Soft-light portrait shot with flash and soft-light box.

There is too much about flash. There are many books on flash photography in the world, and there are also many video tutorials on the Internet to teach the use of flash. So I won't go into details.

Led light

In recent years, with the popularity of LED, more and more LED photographic lights appear. Compared with traditional flashlights, LED lamps have unique advantages.

Led light

The light source of LED is continuous, so when you light it with LED lamp, the picture you take is consistent with the picture you see. Many brands of LED lamps can adjust the brightness of the light source infinitely, and there are bulbs with double color temperature, which can adjust the color temperature of the light source, so that LED lamps can adapt to more scenes and create more effects.

Compared with flash lamp, the light texture of LED lamp is not so hard, and the characteristics of light source are closer to natural light. So when you use it, you will feel more familiar, easier to master and less easy to control than the flash.

Thanks to the small and energy-saving characteristics of LED bulbs, they can be made into various shapes. For example, there is an annular LED light, which can be placed in front of the lens to take macro shots and fill the light for insects, which is very convenient.

However, LEDs also have some disadvantages. Compared with flash lamps, especially with high-power outdoor lamps, the maximum power is quite insufficient. So it is impossible to dim the ambient light with LED.

Intensity of light

According to the intensity of light, it can be divided into strong light and weak light.

Outdoor light on sunny days belongs to the category of strong light. Shooting under strong light has strong impact, hard texture and obvious transition between light and shade. When shooting on cloudy days or indoors, the light belongs to the category of weak light. The light does not directly shine on the subject, but is scattered light. The transition between light and shade is smooth, and the picture is softer, but it is also prone to insufficient levels.

Leaves are very transparent in strong light.

What is weaker than weak light is night shooting. At this time, there is no main light source, and the light is mostly urban lighting and neon lights, and the light sources are also scattered. Therefore, you need to use a tripod to shoot the night scene, because the exposure time will be longer and the composition is also very important.

At dusk, the light is dim, but the light of fireworks is brilliant.

Many people think that the stronger the light, the higher the shooting quality. In fact, this is not correct. The intensity of light is not directly related to the shooting quality. Any kind of light is related to the shooting intention, some themes are suitable for strong light, some themes are suitable for low light, and some night scenes are also very colorful. Quality depends on how you use light. If you make full use of light, you will take high-quality photos.

The Inverse-Square Law

What needs to be remembered is the way the light intensity changes. Although the distance between the earth and the sun is far away, any distance on the ground is not enough to affect the intensity of light, so it is not necessary to consider using natural light when shooting outdoors. However, when outdoor scattered light or flash lamp is used indoors, the light will change with the distance.

Specifically, every time the distance between the subject and the light source is doubled, the intensity of light will drop to a quarter.

Inverse square law of Light

Therefore, when you increase the light source from one meter to two meters away from the model, the light intensity shining on the model is only a quarter of the original. Assuming that the aperture and sensitivity are unchanged, if the shutter speed was 1/200 seconds, it needs 1/50 seconds now. If you don't want the camera's shooting parameters to change, then you have to increase the light intensity of the light source by four times. If you used to shoot with the flash 1/64, you need to adjust it to116 now.

When you use artificial light sources, such as flashlights, you need to pay special attention to inverse square law. If the distance between the light source and the model changes slightly, it is likely that the exposure effect will change greatly.

Treatment of light

Whether we use natural light or self-made light source when shooting, we can process the light or have the artistic effect we want.

With the color filter, you can change the color of the light source and shoot different colors. You can also superimpose filters to create rich light and shadow effects. In fashion photography, this way of dealing with light is especially used.

The left and right light sources use red and blue color filters respectively.

Using the shape filter tool, you can form textured light and shadows. For example, using a shutter to filter light to shoot a model can produce unusual artistic effects.

Grating blinds leave artistic light and shadow on the model, adding color to the photo.

Light processing is an open means, which can provide countless possibilities of combination and further improve the shooting effect. For you, what you need to do is to try various possibilities.

Mixing of light

When using Photoshop to make creative pictures, more than one kind of picture material may be used. Naturally, the light in different picture materials is also different. When designing, we need to pay attention to the nature of light.

The light in the scene should be uniform, and the properties such as the direction, hardness and intensity of the light should be consistent with the properties of the light source, so that the effect looks realistic enough.

At this point, this series of basic photography courses is over. I will take a break and start a more advanced and themed photography course.

Basic course of SLR photography (13)? How to take panoramic photos

Panoramic photos can show a wider perspective than wide-angle lenses, and the picture is more shocking than traditional perspectives.

Panoramic perspective is more shocking than ordinary photos.

Panoramic photos are not new, and many cameras and even mobile phones have panoramic shooting mode. However, these automatic shooting methods have certain limitations, and sometimes they can't generate perfect panoramic photos. Therefore, if you want to take a good panoramic photo, you need to use manual shooting and post-synthesis methods.

Speaking of it, it is difficult to manually shoot the post-synthesis, but it is not as complicated as expected. However, when taking panoramic photos, we need to pay attention to the possibility of photo stitching.

The human brain is amazing. It can put thousands of puzzles together without overlapping parts. But computers can't. Only when two adjacent panoramic photos you have taken overlap, can the computer determine the position relationship according to this overlap and the photos can be stitched together. Therefore, computers are superior in powerful computing performance, but far less intelligent than human brains.

It is necessary to ensure that adjacent photos overlap to a certain extent, so that a panoramic view can be successfully synthesized later.

Before shooting

When taking panoramic photos, try to use a lens with an equivalent focal length greater than 24mm, and a focal length of 35mm is a good choice. When shooting with a wide-angle lens, the shorter the focal length of the lens, the more serious the perspective distortion of the picture, and the greater the possibility of synthesis failure in the later software synthesis. In order to avoid this situation, we should also pay attention to the focal length used in shooting.

You can hold the camera horizontally or vertically when shooting. I prefer to shoot vertically, so that the size of the synthesized picture can be larger and the overall proportion will not be peaceful.

Panoramic photos are usually taken for scenery, and a smaller aperture can be used to ensure a greater depth of field, such as F8 or F 1 1. Another reason for this is to avoid serious dark corners in each photo. All lenses will have dark corners, but to varying degrees. Usually, the dark angle is the most serious at the maximum aperture. After reducing a few apertures, the dark corners will disappear to almost invisible. This is advantageous for splicing.

The next thing to do is to pick up the camera and start shooting. Remember to record in RAW format when shooting, so as to leave enough space for later stage. You can shoot two or three, five or six, or a dozen. It can be 120 degrees, 180 degrees, or it can be a 360-degree photo. However, in order to avoid the computer becoming a dog in the later synthesis, we should try our best to do our best.

5 Zhang Quanjing uses hand-held photography.

Handheld or tripod?

Whether you shoot by hand or with a tripod, both methods have their own advantages.

Almost 99.9% of the hundreds of photos I took of Zhang Quanjing were taken by hand. Okay, I admit I'm lazy. So this is also the biggest advantage of hand-held shooting. You don't need to bother to set up a tripod, then turn around and take the next photo. Hand-held shooting is very convenient and fast.

But the biggest drawback of hand-held shooting is also obvious. Without stable support, it is easy to cause the up-and-down or horizontal angle of each photo to be inconsistent, and jitter will also affect the clarity of the picture. The more you shoot, the better you can grasp the up-and-down or horizontal angle of the picture, so this can be minimized through a lot of practice. Using the anti-shake function of the lens or fuselage can avoid the influence of jitter.

But what if you don't grasp it well, or the lens and body don't support anti-shake, and the shutter can't reach the safety shutter? It's safest to shoot with a tripod. A tripod can ensure that the photos you take are clear enough, and the up-and-down or horizontal angle of each photo is the same.

If conditions permit, try to use stereo pan-tilt instead of spherical pan-tilt. Three-dimensional pan-tilt can only adjust one dimension, and spherical pan-tilt can hardly adjust the horizontal angle without affecting the vertical angle. Fortunately, some spherical ptz have panoramic shooting function, and the bottom has a rotatable shaft, which is convenient for panoramic shooting.

Three-dimensional tripod head (left) and spherical tripod head (right)

In the later synthesis

The post-synthesis work needs to be done on the computer. There are many kinds of panoramic production tools on the market, most of which are easy to use and stupid enough. But here, I don't want to introduce separate software, because Lightroom and Photoshop, which are indispensable for post-processing, support the synthesis of panoramic photos, and I believe these two softwares are also the most widely used by photographers. I will explain how to make panorama for these two softwares.

First of all, I will not explain all the steps of the software step by step, just as I will not explain the specific operation when I explain the principle of photography. You should read the instructions yourself for the specific operation. So I think you have a certain foundation of software operation, so I will only talk about the operation methods involved in this topic.

lighthouse

Import your panoramic photos into Lightroom, then select each picture of the panoramic photos, click the right mouse button, and select Photo Merge from the pop-up menu? Panorama (panorama)

Panoramic preview generated by Lightroom

At this point, Lightroom will automatically try to stitch the panoramic photos and generate a preview. When generating a preview, you can choose to automatically cut off the blank part and adjust the correction intensity of lens distortion. After making appropriate adjustments, click OK and Lightroom will automatically generate photos of Zhang Quanjing for you. The whole process is highly automated, and there are few manually operable parameter adjustments. If the previous shooting is good, the panoramic synthesis effect of Lightroom is very good.

The automatic editing function can discard blank parts from content clips.

Since Lightroom CC 20 15.4, the function of boundary distortion has been added to panoramic mosaic. There are some transparent areas in the previous mosaic panoramic images, which are usually cut inside, but many pixels will be lost. The new edge distortion function can automatically distort the edge to fill the blank area of the picture, and the effect is quite good. It is recommended. When you adjust the parameter to 100, you can fill the whole picture, so you won't waste pixels.

Edge distortion can fill the transparent area and make the photo larger than automatic cropping.

It should be noted that the edge distortion function will deform the lines in the photography of architectural themes, which looks like the perspective of fisheye lens, and the perspective can be adjusted later.

If you shoot in RAW format, Lightroom will generate a file in DNG format, which is an ordinary RAW file. You can have enough space to post-process the picture.

To modify (a picture or photograph) with a computer.

Compared with Lightroom, Photoshop has more freedom, but it is also more difficult. Start Photoshop first, and then click the file? Automation? Photomerge (photo mosaic)

Picture mosaic window in Photoshop

At this time, in the pop-up window, you can choose the splicing method of the left panorama, which depends on how you shoot it. Usually you can choose automatic mode, and Photoshop is also quite intelligent. At the top right is a list of pictures that need to be spliced. Add pictures that need to be spliced. Photoshop supports files in JPG format and files in RAW format directly.

There are several options below to blend images together, which should be selected. It is recommended to check the vignetting, so as to ensure that the edges of the two pictures will not appear obvious unnatural brightness because of the dark angle of the lens. Geometric distortion correction: When you use a wide-angle lens, for example, when the focal length is less than 35mm, the perspective distortion around the picture will be obvious, which will affect the final effect when stitching. If this option is selected, Photoshop can make some corrections. Of course, these options are time-consuming, but I think it is worthwhile for the final output of high-quality photos. I don't think it is necessary to check the final content consciousness to fill the transparent area, but it takes time.

Panorama synthesized by Photoshop

The rest is just waiting for Photoshop to process it automatically. The better the computer performance, the less time it takes to make a phone call. After Photoshop finishes stitching, each Zhang Quanjing will become a separate layer, and then the parts that need to be displayed will be reserved with layer mask. Manual adjustment can be made for the imperfect parts of Photoshop automatic splicing. More layers will take up a lot of space, so when you are satisfied with the panoramic mosaic effect, I suggest you merge the layers.

Photoshop creates a layer for each picture and masks it.

Unlike Lightroom, Photoshop needs to be saved manually. It is suggested that you save a high-quality source file in PSD or TIFF format, and then save a separate file in JPG format for network sharing and other purposes.

Requirements for computer performance

The synthesis of panoramic photos requires high computer performance for post-processing. The higher the pixel of the camera, the more photos you take, and the higher the requirements for the computer. Otherwise, the computer will be stuck for a long time, which may cause the computer to crash in serious cases.

Therefore, whether dealing with the synthesis of panoramic photos or general post-processing, it is best to ensure that the computer can have sufficient performance, especially the size of memory, which is very important for panoramic synthesis. The data processed by the computer is stored in the memory. After using 5 years 16G memory, it is found that the system can't cope with taking too many panoramic photos with 36 million pixels sometimes. So I bought a new machine last week, equipped with 64G memory, which can guarantee that it will last for a long time. So for reference, I suggest that you'd better use 16G memory, at least not less than 8G.

System performance occupation when splicing 5 computers with 8G memory and 36 million pixels.

When I tried to splice five 36-megapixel panoramic photos on the company's computer with only 8G memory, the memory and hard disk occupied extremely high. When the memory is insufficient, the system will write the redundant data into the virtual memory on the hard disk, and then read it out from the virtual memory on the hard disk when the memory is sufficient. So if the memory is not large enough, try to use a solid-state hard disk, which will be much faster than a mechanical hard disk.

It is not difficult to take panoramic photos, and the post-operation on the computer is also very simple. Some key points need to be paid attention to in the early shooting, and after a lot of practice, a perfect panoramic photo can be taken.