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1、数码摄影入门常识（Introduction to digital photography）1. What do you mean by F2.8-4/ or F3.5-F5/F7.6-F11 in the cameras parameter table?Answer: the F value of the camera lens aperture is not only a problem of aperture, but the actual amount of light is expressed. It is also related to the focal length of the
2、 lens. It is a relative value. For a general zoom lens, even though the apertures physical aperture is constant and the focal length becomes longer, the amount of light will be smaller and the aperture F will be smaller. F3.5-F5/F7.6-F11 said: the maximum aperture at the wide-angle end, the short fo
3、cal length is F2.8, in the long end of the zoom, the longest focal length is F5; the minimum aperture at the wide-angle end, the short focal length is F7.6, in the long end of the zoom, the longest focal length is F11.Of course, the advanced professional lens has a constant aperture, that is, the F
4、value does not change with the focal length. In fact, when the zoom is in, the physical diameter of the iris changes accordingly. A lens with a constant aperture is much more expensive than a lens of the same quality.2, why the digital cameras smallest aperture is not small enough, such as C-700 is
5、F8, N995 is F10, and the traditional camera at any time F11, F16 or even F22 why?Answer: we usually say F2.8, F8, F16 aperture, aperture coefficient, relative aperture, aperture and aperture is not physical, physical aperture and lens aperture to the photosensitive device (film or CCD or CMOS) is re
6、lated to the distance.When the aperture aperture is constant, the centre of a lens and a photosensitive device distance farther, the F number is small, on the contrary, the centre of a lens and a photosensitive device nearer, through the light hole to the optical density of photoreceptors is higher,
7、 the greater the number of F.Most non professional digital camera lenses have short focal length and very small physical aperture. When F8, the aperture of the aperture is very small, and the optical phenomena such as diffraction will continue to be reduced to influence imaging. Therefore, the gener
8、al non professional digital camera minimum aperture in F8 to F11, and professional digital camera photosensitive device area is large, the lens from the photosensitive device far away, the aperture value can be very small.3, what is bracketing exposure? How to use?Answer: surround exposure (Bracketi
9、ng) is an advanced feature of the camera. Although metering techniques are becoming more sophisticated, photometric deviations may still occur due to light conditions and subject changes. In order to prevent errors and missing important metering subjects, in many high-end traditional cameras have be
10、en introduced to the bracketing function, when you press the shutter, the camera is not a shot, but by the exposure of different combinations of continuous shooting more than one, so as to ensure always has a consistent with the photographers intention of exposure.In digital cameras, not only the in
11、troduction of exposure to the exposure of the exposure, and some cameras can even white dialogue, focusing, etc., surrounded by shooting.4, how to adjust exposure in auto exposure mode?Answer: Although the camera automatic metering technology is increasingly perfect, the central focus of metering, m
12、etering etc. partition are becoming more and more intelligent machines are machines, but still have time, uncertainty, if the subject brightness distribution is not uniform, such as in front of the bright background light portrait photos, is easily influenced by the background the brightness of the
13、characters is underexposed, then use the AE lock or exposure compensation to solve this kind of problem, exposure compensation device of the camera can +2, +1, 0, -1 and -2, if the subject is underexposed, with compensation, increase exposure, and the use of negative compensation, reduce the exposur
14、e.5. What is shutter priority automatic exposure?Answer: shutter priority automatic exposure, also known as shutter automatic pre exposure, is one of the automatic exposure method. Suitable for shooting moving body or need long time exposure shooting situations, according to the intention to select
15、the shutter speed, large moving objects need solidification, selected high shutter speed (such as 1/1000, F1/2000 or more), to shoot at night, flash synchronization, virtual moving body with slow shutter speed (such as 1/30 1, /2 or even longer, but dont forget to use a tripod and a remote control c
16、amera based on CCD, oh) (or film) sensitivity and scene brightness to adjust the aperture size, in order to reach the correct exposure.6. What is aperture priority automatic exposure?Answer: aperture priority automatic exposure, also known as automatic aperture first exposure, automatic exposure is
17、one of the ways. Apply to the control of the depth of field shooting situations, according to the intention to select the aperture, large depth of field, the selected small aperture (such as F8, F11 or less), small depth of field, virtual background, using large aperture camera (such as F2.8), accor
18、ding to CCD (or film) sensitive and the scene brightness to adjust the shutter speed to reach the correct exposure.7, what is the AE lock?Answer: AE is the abbreviation of AutomaticExposure automatic exposure control device. The AE lock is locked in a certain AE setting,For automatic exposure, artif
19、icially control exposure. For example, in the backlight portrait, if the average metering automatic exposure, as will be underexposed, if the first to face the spot, and press AE to lock the exposure value, the shooting will be according to the brightness of the Department to ensure the normal expos
20、ure, body exposure.8. What is program automatic exposure?Answer: programmed automatic exposure is a product of the combination of electronic technology and artificial intelligence. In this way, the camera can not only calculate the appropriate exposure according to the light conditions, but also aut
21、omatically select the right combination of exposure. However, program exposure is not a panacea, and ultimately a selection of exposure combinations. Experienced photographers prefer to use manual exposure.9, is the shutter delay time of the digital camera longer?Answer: a mistake many novice photog
22、raphers often make is shooting just staring at the viewfinder, see the shot when the time comes suddenly when the camera needs to press the shutter, automatic focus, exposure metering, calculating and choosing the appropriate exposure. Of course need time, if this also belongs to the shutter delay,
23、then the shutter delay is not unique to digital camera, auto focusing, automatic metering of the traditional camera will also have this phenomenon. The correct approach should be to press the shutter first, let the camera complete automatic focus, automatic exposure and other preparatory work, the s
24、hooting time, and then press the shutter to the end, so that the shutter delay is almost no or very short. Of course, when you snap in is difficult to do so, our advice is: using a digital camera to capture the best focus manually preset focal length, predetermined exposure, using manual exposure of
25、 course, only high-end models will allow you to do so.10. What is the shooting interval of the digital camera?Answer: the shooting interval mainly refers to the digital camera each took a photo to data processing, including computing and storage, take some time, as can take second pieces of traditio
26、nal camera that once finished, it may be difficult to overcome the problem of ordinary digital cameras, only professional digital camera and individual in order to high-end models built in large high speed continuous multi cache. Our advice is: if you have to shoot quickly and continuously, try to u
27、se the lower resolution as much as possible, because the amount of data is smaller and the processing speed will be much faster.11, when I use digital camera to take pictures, I always feel that everything is clear. Even if the focal length of the camera is equivalent to 200mm, it is difficult to ac
28、hieve the shallow depth of field effect of traditional camera. Why?Answer: this question can be understood: to use the traditional camera professional digital camera as an example, because the imaging device (CCD or CMOS) area is less than the traditional camera film area, so the focal length is equ
29、ivalent to 35mm camera xxmm , but the equivalent is equivalent to the view, shooting not all equivalent.You can imagine that CCD (CMOS) is to cut a piece of film to digital images from the central image and depth of course, using the film is the same, so generally speaking, the actual physical focal
30、 depth and aperture and lens only about. When you say equivalent to 200mm, the cameras physical focus is about 30mm (different models will vary), which belongs to the wide-angle lens in the traditional 35mm camera, and the depth of field is of course great.It is said that Carl Zeiss Company has a ca
31、lculation formula, physical focal length of about 30mm digital camera, extrapolated out, depth of field effect is probably equivalent 70mm or so, far from the angle of view equivalent 200mm.12, in the introduction of OLYMPUS digital cameras, often see TTLiESP automatic focus argument, in the end wha
32、t is the concept?Answer: TTL is the abbreviation of English ThroughTheLence (through lens). IESP is the abbreviation of English IntelligentElectroSelectivePattern, which is translated as intelligent electronic selection mode.The use of iESP automatic focusing system for digital camera do in the focu
33、s of multiple blocks within the partition (with the information that way split fan-shaped, segmentation) and then divided by the measured focus position block integrated operation, according to the different state of the subject, determine the best focal position.IESP is also used for the automatic
34、exposure system and white balance detection system, the average block segmentation the measured brightness weighted after the exposure of the reference value, in different circumstances, the segmentation block weighting of portrait and landscape will be different.OLYMPUS made a lot of work in this r
35、egard, the program recorded on camera IC, because the single zone location intelligent weighted function of iESP is far better than the traditional and average metering technology, so OLYMPUS was reluctant to use the old term to call iESP.13. What is auto focus TTL?Answer: TTL is the abbreviation of
36、 English ThroughTheLens (through lens).There are many ways to implement auto focus, but there are two kinds: automatic and passive.Early camera, take a similar visual measuring mode to achieve autofocus camera, an infrared emission (or other radiation), according to the reflection of the subject to
37、determine the distance to the subject, and then adjust the lens combination according to the measured results, realize automatic focusing. The af - direct, fast, easy realization and low cost, but easy to make mistakes (camera and photographed with other things such as glass can not be achieved betw
38、een accuracy, AF) is also poor, now high-end cameras generally have not used this way. Because it is the camera active emission ray, so called active, and because it is actually just distance measurement, not through the lens of the actual imaging to determine whether the correct coking, it is non T
39、TL.Compared with the active AF, later developed a passive auto focus, which is according to the actual imaging lens to determine whether the correct judgment is based on general coking, contrast detection, the principle is very complex, not the scope of this article. This method is realized by lens imaging, so it is called automatic focusing of TTL. It is due to the auto focusing method based on lens imaging, so the focus of high precision, low error rate, but the technology is complex, the slower (except by ultrasonic motor advanced automatic focusing lens), the cost is also high.