Traditional Culture Encyclopedia - Photography major - What's the use of zooming skills?
What's the use of zooming skills?
Introduction to scaling
The so-called zoom capability includes optical zoom and digital zoom. Although both of them are helpful to enlarge distant objects when shooting at a long distance, only optical zoom can support the image subject to add more pixels after imaging, making the subject not only bigger but also relatively clearer. Usually, the larger the zoom factor, the more suitable for telephoto shooting. Optical zoom, like traditional camera design, depends on the focal length of the lens, so the resolution and image quality will not change. Digital zoom can only reduce the size of the original image and make the image larger on the LCD screen, but it does not help to clarify the details.
Use the technique of scaling
Norman rothschild, an American photographer, has accumulated a lot of valuable experience in the practice of using zoom lenses for many years, which is summarized as the following 10 for the reference of photographers.
1, long focal length focusing. When using zoom lens, the correct focusing method is to focus with a long focal length first, and then choose the appropriate focal length to shoot; Because under the long focal length, the image of the subject is the largest and the depth of field is the smallest, which is convenient for accurate focusing. In the case of backlight or complicated light, it is also helpful to choose a suitable area for metering, and it is not necessary to be close to the subject for metering. Usually, when shooting, we often use a zoom lens with medium and long focal length as the main lens, focus on metering with the longest focal length, and then select the ideal focal length after locking the exposure, so that we don't have to move back and forth.
2. Try more at each focal length. Although most photographers are extremely concerned about the zoom magnification of the zoom lens, they often use the long focal length at one end, and some even regard it as a fixed-focus telephoto lens. In fact, when you try to use other focal lengths to get a completely different picture, you will find that the zoom lens has considerable potential as a variable framing tool.
3. Be familiar with the operation of zoom lens. In the early zoom lens, zoom and focus were adjusted by two rings respectively. Most zoom lenses are changed to single-loop control, which is characterized by changing the focal length by pushing and pulling the lens back and forth and rotating it left and right. Therefore, for photographers who have just bought a new mirror, they should be familiar with and keep in mind the front and rear direction of zooming and the left and right position of focusing, so as to avoid the influence of slightly turning the adjusting ring when zooming after precise focusing. This is why many more "conservative" photographers prefer to use the old-fashioned double-ring zoom lens.
4. Correct use of the bracket. When using a zoom lens with a focal length of more than 200mm, the lens should be fixed on a tripod and other brackets to ensure the stability when shooting.
5. Choose a suitable range hood. Zoom lenses are more prone to halo than other types of lenses, so a suitable hood is essential. Sometimes the occlusion caused by the hood is invisible on the viewfinder of a single-lens reflex camera, but it is displayed on the film. This situation is most obvious when shooting in a small aperture, which often causes the hood to fall into the depth of field. In addition, some hoods are effective at the long focal length end, but when zooming to the short focal length end, there will be vignetting caused by occlusion that cannot be seen on the viewfinder. Therefore, it is very important to choose a suitable hood for the zoom lens and use it reasonably.
6. Add a range finder. If you need to use a long focal length, you can change your 70-2 10 mm lens into a telescopic zoom lens of 140-420mm at will for a little money, and the triple zoom lens can even reach 2 10-630 mm, so that your lens can immediately rank among the astronomical telescopes. But the price will be the loss of aperture series and the clarity of the photos taken. For example, if a F4 zoom lens is equipped with a 2x rangefinder, the aperture will lose 2 levels and become F8; After adding 3 times the range finder, the maximum aperture becomes F 1 1. As you know, the best resolution of the lens should be to choose an aperture 2 levels smaller than the maximum aperture to shoot. Therefore, high-speed film and tripod must be considered when adding rangefinder, and the subject should be still.
7. Use the filter carefully. Don't add a filter to the zoom lens unless it is really necessary. You really need a protective glass on the beach or in salt water. In order to change the color temperature and create special effects, such as deepening the color of the sky and eliminating reflection, polarizers are needed. In addition, adding some optional filters will only increase the reflection problem inside the lens, which is already a headache.
8. Control the depth of the picture. Shoot with a zoom lens at a distance of 1.5 meters, with a focal length of 60mm, and shoot at a distance of 7.5 meters, with a focal length of 300 mm. The images of the subjects in the obtained photos are the same size, but the depth of the two photos is different. Photographs taken with a focal length of 60mm have a sense of depth and space in the background; 300mm focal length shooting gives the impression that the scene is compressed and the subject and the scene seem to be "closer".
9. Keep a distance to prevent deformation. When shooting with the wide-angle end of the zoom lens, attention should be paid to keeping a proper distance from the subject to avoid deformation of the subject. It must be remembered that the main factor affecting the perspective effect is the distance when shooting, not the focal length.
10, the trick to control the depth of field. You can do an experiment. You can use the same aperture and the same focal length to take two photos with the same distance of 25mm and 50mm respectively, and then enlarge the photos with the focal length of 25mm to make the subject in the picture as big as that of 50 mm. After comparing the backgrounds of the two photos, it will be found that the background in the enlarged photo is not as hazy as that in the first photo, and actually a more useful depth of field is obtained. This method is also effective when applied to fixed-focus wide-angle lenses.
optical zoom
The English name of OpticalZoom is Optical Zoom, and digital cameras rely on optical lens structure to achieve zoom.
The optical zoom mode of a digital camera is similar to that of a traditional 35mm camera, that is, the scene to be shot is enlarged and reduced by moving the lens. The larger the optical zoom factor, the farther the scene can be shot. Compared with the camera with weak zoom efficiency, the far-end shooting with focus adjustment is relatively clear.
Optical zoom is achieved by changing the positions of lens, object and focus. When the image plane moves in the horizontal direction, the visual field and focal length will change, and the farther scenery will become clearer, making people feel that the object is moving forward.
Obviously, there are two ways to change the perspective. One is to change the focal length of the lens. In photography, this is optical zoom. The focal length of the zoom lens is changed by changing the relative position of the lens. The other is to change the size of the imaging plane, that is, the diagonal length of the imaging plane. In digital photography, this is called digital zoom. In fact, digital zoom does not change the focal length of the lens, but changes the viewing angle by changing the diagonal of the imaging plane, thus producing an effect equivalent to the focal length change of the lens.
Therefore, we can see that some digital cameras with long lenses have more room for moving the internal lens and photoreceptor, so the zoom factor is also larger. We see that some ultra-thin digital cameras on the market generally have no optical zoom function, because the movement of the photosensitive device is not allowed in the fuselage at all, while the optical zoom function of "long lens" digital cameras such as Sony F828 and Fuji S7000 is as high as 5 or 6 times.
digital zoom
DigitalZoom, English name is digital zoom, there are two kinds of digital zoom:
One is to enlarge the area of each pixel in the picture through the processor in the digital camera, so as to achieve the purpose of enlargement. This method is similar to using image processing software to enlarge the area of a picture, but the program is carried out in a digital camera. Some pixels on the original CCD image sensor are enlarged by interpolation, and the pixels on the CCD image sensor are enlarged to the whole picture by interpolation algorithm.
The second refers to Nokia's pureview technology. The core of PureView technology is to "condense" an image with 465,438+0 million pixels into an image with 5 million pixels, which is the process of "oversampling". In practice, every 8 pixels will be integrated into a "super pixel". PureView technology is not only amazing pixel value, but also high-quality optical technology and intelligent image processing technology. At the same time, due to the huge number of pixels, the volume of the 4,654,380+0 million pixel sensor will increase accordingly, which makes another major feature of PureView technology: lossless digital zoom. When shooting, the phone will display the image at the level of 5 million pixels. When you enlarge the image, the degree of "over-sampling" will be reduced until a "super pixel" is restored to an ordinary pixel. This process is different from the interpolation algorithm used in general digital zoom, and will not lose the accuracy and clarity of the image. Such a "violent" digital zoom method makes our mobile phone truly become a photographic weapon comparable to a professional camera equipped with an optical lens.
Different from optical zoom, digital zoom is the change of the vertical direction of the photosensitive device, which gives people a zoom effect. The smaller the area on the photosensitive device, the user can only see the scenery in this area visually. However, because the focal length has not changed, except for pureview technology, the image quality is worse than normal.
The total zoom number of a digital camera is calculated as follows: For example, the optical zoom of Sony F7 17 is 5 times, while the digital zoom is 2 times, so the maximum zoom number is 10 times. Digital zoom in digital cameras can usually be turned off. In addition, there is a brand-new and unique Sony intelligent zoom function, which can enlarge the zoom shooting without enlarging the particles, so that the enlarged image can maintain the original detail quality. Intelligent zoom provides different degrees of enhanced zoom function according to the choice of different image sizes. Unlike digital zoom, intelligent zoom can keep the image quality the same as the original image. Use the technique of scaling
- Previous article:Which shooting base in Hangzhou is better?
- Next article:Men always peek at these parts of women.
- Related articles
- Is home improvement design easy to learn?
- Can I get a business license without joining Shaxian snacks?
- Huzhou tourist attractions raiders Huzhou tourism must go to the top ten attractions.
- I am "pushing the mill" in a state-owned enterprise
- What is the name of the cormorant?
- Why do middle-aged aunts love to hold a lot of scarves when taking pictures?
- Wechat nice nickname girls are simple and generous, and Wechat name girls are simple and temperament.
- If you want to travel, what are the suitable travel shots?
- Marriage related matters (Shunyi District)!
- How to shoot a three-screen video tutorial in Tik Tok