What is the relationship between focal length and shooting distance in SLR shooting?

Lens focal length and shooting distance

Background blur is a common and frequently used phenomenon in portrait photography, which is closely related to the focal length of the lens used, the brightness (aperture value) of the aperture and the shooting distance (the distance from the camera to the subject). The longer the focal length is, the easier it is to blur the background when the aperture value of the lens is constant. Of course, if the focal length is the same, the brighter the aperture, the easier it is to produce blur effect. In addition, the degree of background blur will change with the change of shooting distance. The shorter the shooting distance, the closer it is to shooting, and the greater the blur effect. Therefore, if you want to get a sharp blur effect, you should choose a lens with shorter shooting distance, brighter aperture and longer focal length. Only when taking portrait photography, first determine the focal length of the lens, and then fix the shooting distance after the composition is completed. Therefore, while mastering the basic principle of blur, we also need to master the relationship between lens focal length and shooting distance.

Shooting distance

1:less than the nearest shooting distance of the lens used in shooting, shooting is not allowed. ※.

2. Shoot with a 35mm full-frame camera. ※. Brackets indicate the lens focal length required when shooting with APS-C camera under the same conditions.

Grasp the relationship between focal length and shooting distance with numerical value, and use it flexibly in shooting scenes.

The relationship between the size of the subject in the photo and the shooting distance is shown in the above table. The longer the focal length, the longer the shooting distance, so as to keep the size of the subject on the screen unchanged. If the height of the subject is 167 cm, if you want to take a close-up above the chest, the shooting distance with 16mm lens is so short that you almost touch people, while the distance with 200mm lens must be more than 3 meters. If you can remember this value to a certain extent, it is easy to grasp what kind of focal length lens should be used to shoot the scene. Especially when shooting indoors, it is impossible to keep a certain shooting distance from the model in most cases. If you want to take a full-length photo, it is almost impossible to use a lens with a focal length of more than 200mm unless it is such a wide place as a gymnasium. Grasp the approximate relationship between lens focal length and shooting distance, and you won't hesitate when choosing a lens.

Shoot with a 35mm full-frame camera

Even a wide-angle lens that is considered to be difficult to blur will produce a certain background blur effect when the aperture is large enough, the shooting distance is close, and the subject is far from the background. But at the maximum aperture, there is already a certain depth of field. When the aperture is around F4, the background is already clear. Judging from the effect of the picture, you can still feel a certain blur effect until F5.6, and the image taken with a smaller aperture is similar to the pan-focus effect. If the background is closer to the subject, the fuzzy aperture value will be smaller at first, and it may be difficult to capture the fuzzy effect around F4.

After the focal length is changed to 35mm, although it is still a wide-angle lens, the depth of field is still much smaller. The blur effect when the aperture is F2.8 is greater than that when the aperture is 16mm. The blur felt from the legend is similar to the blur effect between F4 and F5.6 when shooting with a 50mm lens. Compared with 16mm lens, the visual angle has changed, and the blur effect is similar to that of 50mm lens, but the impression of the photo is slightly different due to different visual angles.

Detailed explanation of SLR lens parameters

Lens properties: usually indicate whether the lens is AF mount or EF mount, and usually include some lens type identification;

Focal length parameter: indicates the focal length range of the lens, in mm;

Aperture parameter: indicates the maximum aperture coefficient of the lens, and some lenses also indicate the minimum aperture coefficient of the lens;

Features: It represents the characteristic technology adopted by the lens. This is also the content to be explained later.

This information is usually expressed as "Canon zoom lens EF-S10-22mm1:3.5-4.5USM". According to this information, we can judge the complete parameters of this lens: Canon original EF-S electronic bayonet automatic zoom lens; Focus range 10-22mm (super wide angle 2 times zoom); The maximum aperture coefficient is 3.5-4.5; USM ultrasonic motor is adopted.

Jiao Duan introduced:

The focal length of 10mm is an ultra-wide-angle focal length. Mainly used in landscape photography, documentary photography and so on. The angle is very big and has a great influence.

The focal length of about 24mm is a small wide angle, which is mainly used for landscape photography and documentary photography. This focal length is suitable for souvenir photos.

The focal length of about 50mm is the standard focal length, the visual angle is approachable, and the deformation is small. It is mainly used for landscape photography, portrait photography, documentary photography and so on.

The focal length of about 85mm is medium focal length, which is mainly used for taking portraits, still lives and so on.

The focal length of about 200mm is telephoto length, which is often used for snapshots and close-ups.

The focal length of about 500mm is a long focal length, which can be used to shoot birds, that is, birds.

With a telephoto lens of more than 500mm, it is more convenient to shoot birds, and it is also easy to sneak shots in the distance of the playground.

Telephoto and ultra telephoto are often used in sports photography.

What are the skills of mirror shooting and reflection shooting?

1. Grasp the shooting angle

Every rainy evening, you can see a group of photographers "squatting" at major scenic spots. The reason why we use such a tiring shooting posture is because the reflection is closely related to the shooting angle. As long as the angle between the camera and the water surface is corrected, the reflection in the picture can be changed. Take Bao 'an Palace as an example. The closer the lens is to the water, the more complete the reflection of the security palace is. Simply put, the number of reflections in the picture is inversely proportional to the height of the viewpoint. In addition, the number of reflective surfaces will also have an impact. For example, because the coverage area of stagnant water is limited, it is even more necessary to actively find a suitable shooting angle to present an ideal picture.

In landscape photography, the reflection of water is a frequently used element. In addition to water accumulation after rain, there are lakes, rivers, ports and ponds. Reflection can be seen everywhere. Does it mean that no matter what kind of water reflection is taken, the camera must be close to the water surface? Actually not, because we have to consider the distance between the reflection and the photographer. The farther the distance is, the reflection and the real scene are almost in the same proportion, and the height of the viewpoint will not have much influence. For example, when shooting the Lanyang Museum, you don't need to use a very low angle, just include the reflection and the real scene in the mirror. Distance is also related to the choice of lens focal length. For example, in the Cuihu Lake of Sun Yat-sen Memorial Hall, a super wide-angle lens must be used to fully accommodate the simultaneous reflection of1kloc-0/building and lake water.

Step 2 skip the standard framework

When shooting the subject of reflection, mirror symmetry is often adopted, which divides the picture into two parts, presenting a neat and orderly aesthetic feeling and strengthening the momentum of the image. Sometimes you can jump out of this box and try to change the ratio of the real scene to the reflection in the picture, and maybe there will be unexpected gains. As for how to allocate the proportion, it depends on the focus of the image, and the position of the focus is the same. If you have special needs, it is not bad to focus on reflection. In addition, you can turn the photos upside down, which is the fun of dealing with such subjects. This is usually due to several considerations. For example, because of the material of the reflecting surface, reflection is more interesting visually than the real scene. Or because the artistic conception is abstract, the reflection is naturally more appropriate than the real scene. Another possibility is that the reflection retains more details than the real scene, because the reflection will be underexposed and the highlights on the screen will not be overexposed easily, so the photo will be reversed, which will enrich the details of the subject.

3. Narrative presentation

There are many media that can form a reflection, such as car body, windows, glass curtains, water droplets, smooth walls and floors, and even the pupils of eyes. As long as you pay more attention, you can find interesting reflections and even shoot stories. Sometimes the real scene doesn't have to be stored in the photo with the reflection, and the reflection can be used as a foil to echo other themes. For example, when shooting the moment when the bride throws a fan in the wedding record, you can pay a little attention to the family figure reflected in the window and bring it into the picture to convey the current emotional atmosphere.

When the reflection is more interesting and meaningful than the real scene, focus on capturing the reflection picture. Sometimes it is found that the seemingly inconspicuous subject is particularly eye-catching in the form of reflection, which may be because the subject becomes a silhouette in the reflection, and its outline shape is more attractive, or it may be because the reflecting surface filters out the original messy background and makes the viewer's vision more focused. In addition, sometimes only intermittent local reflections, such as groundwater, can not see the complete face of the real scene, but can add a lot of imagination and fun. The water surface is usually a very interesting theme, which can easily present a fantastic virtual world and show different visual effects in different lighting environments.