How to choose the light correctly?
Only examine expressing and appearance of the automatic camera, the course of making the correct choice exposed is simpler and convenienter and simpler and convenienter.
Examine and only express the light power that can be measured and shone on the object, and show its reading as the diaphragm and shutter speed. Examine and only express and can basically be divided into a incidence type and reflected two kinds of formulae.
The incidence type examines and only expresses the light quantity thrown on the object directly in measurement, it is very convenient to use, examine, express, prefix object only, spheroid facing each other scene of camera half transparent, half that express, then can follow the instruction and is exposed. The incidence type examines the biggest shortcoming that is only expressed, is that it is unable to measure the light quantity that the subject reflects out, and the main light quantity of acting on film, is exactly this part. In addition, use this kind to examine and only express, it is impossible for the cameraman to be close to the subject to examine the light sometimes, should give consideration to a lot of subjects sometimes, and among them - -Some are in the shade, it is difficult to function that the incidence type is examined and only expressed.
The reflecting type examines and only expresses and measures the light reflected by the object. Machine of camera examine, express only, person who reflect all usually, express towards the direction of measuring only examining only use. But some problems that it exists. Majority person who reflect examine angle measured to express very wide only, take a photograph of into subject around very bright or dark, examine, can express quilt only " Deceive " ,Offer the wrong one to expose the materials, cause the subject to be under-expose or excessive.
Now though some reflection types examine and only express and can measure a smaller range, the putting inside of some cameras only expresses and has this kind to examine too " The focal point " Performance that measure, can prevent average reflection type from examine, express in pass bright or pass error that cause under dark background reflect only, but still user must use one's head.
Suppose that there are a black subject, gray subject and a white subject the middle one in a picture. If examine and only express the gray subject of measurement with the reflecting type, it will offer a certain reading of exposing, 125 seconds such as l/, F8; Go again measurement getting white subject that, more light quantity will reflect, get examine smooth body, so examining will offer too few one to expose to only express, such as 1/ 125 seconds, F16; The black subject of measurement that and then go, will propose more one is exposed, such as 1/ 125 seconds, F4.
In this case, choose how many datas come until the picture correct to expose reading on earth? Through testing proving, should select for use and examine it from the reading of exposing of the gray subject. This is because it is subject to that gray to examine the tune-up that is only expressed when suitable for. No matter how the mere source of reflection measured is, so long as expose reading to shoot according to it, ask the dust is adjusted in the photo obtained will be presented.
If expose according to the reading of the gray subject, then, will the original one appears in the photo gray in the gray subject, because black subject enters less light quantities, will demonstrate in the photo black, because the white subject enters more light quantities, it seems that brighter is white.
If according to getting black reading of subject come, expose, whole exposure of picture can than getting gray increase two diaphragm subject offer, so, black subject will display in the photo gray, as for that gray subject and white subject, will become very white and very bright because of reflecting more light quantities, thus make the whole picture over-exposed. Same, if according to getting white reading of subject come, expose, expose than getting gray reading subject offer dwindle two diaphragm while being whole, so, the white subject becomes gray in the photo, gray and black subject, will demonstrate black or dark-grey because of entering less light quantities, the whole picture will be under-expose.
Therefore, if hope to get the correct one while using the reflecting type and examining and only expressing and is exposed, take, think any time, in order to confirm subject of tone belong to, in the picture, use it as and examine all basis, then go to measure the darkest and brightest position in the picture, compare them with middle tone looks, thus really know whether their level could be kept.
L of American photographer Jacobs sum up, use, examine, express, may cause, it examines to be only wrong 3 situation only, have put forward the method solved:
"The first kind of situation is a backlight. The background is only strong, shoot the target darkly, it will cause under-exposely to only express and expose according to examining. Can regulate the diaphragm by manual means at this moment, hold the great diaphragm or just slow down the shutter speed, or add and use assisting to light.
"The second kind of situation is that a background is on. It is on too to shoot the target. For example shoot the person in white clothes in the courtyard which white snow covered with in front of the white wall. If will seem insufficient according to examining and only expressing reading to expose. Reason very simple, examine, it expresses to be can getting white to regard as person who reflect gray of 18% all these only. Certainly, nobody hope for and shoot white snow into a dusky one, the reason why should transfer great first grade of the diaphragm, or slow down the pace - Block it. Some photography fans are often under-expose on purpose while patting the snow scenes, thought that patted the good snow scenes like this, actually this is not so.
"The third kind of situation is that a stable factor background is dark, it is dark too to shoot the target. Treatment method and the first kind of situation are opposite at this moment. Spread the dark tablecloth on the desk, is showing the book of a black front cover above, if according to examining and only expressing and pointing out that is exposed, tablecloth and book all will be gray, so should turn down first grade of the diaphragm while exposing, raise by one gear shutter speed. "
Though the modern automatic camera is multiple functional, easy to operate, most advanced examining through the lens is only systematic can even deal with the thorny situation like backlight, but it is still a kind of skill that the choice is exposed. It involves photographer one. People's taste and question of the style, but not can replace with a kind of accurate technology.
Photographer John ' Irwin thinks then: "Examine the light manually and still have great potentialities. Moreover, manual operation can make you expose and control voluntarily. "
Irwin points out then: "The manual mode means that the cameraman decides the diaphragm and shutter speed, while photographing, light or take a photograph of body change, must until one or both carry on manual adjustment among them.
"Film pace, light intensity, shooting and moving the body, preventing the vibration of camera and choice that the depth of field is all influencing shutter speed and diaphragm. In order to use IS0100/ 21 under the bright light. The film is taken a photograph of, fetch F8, model of 1/ 125 seconds to expose for the example, in choice diaphragm and pace, need to consider vibration, motion state and depth of field of the body taken a photograph of of the camera.
"If use 50mm standard lens, the shutter speed of 3/ 125 seconds can well prevent the shaking of the camera, unless but if it use scene of 200mm, be the fuzzy in image,and 1 /. Whom shutter speed for 125 second can solidify as car does taking exercises fast take a photograph of into the body. Use the lens of 28- 200mm, shoots with F8, the depth of field is normal, however, some images need the definition, deep and clear can distinguish, simple instead of the atmosphere of losing.
"For meet special requirement these, F8, 125 seconds such as I/ expose, need adjusting; In order to defend enterprise's camera vibration, choose F4, 1/ 500 seconds; In order to solidify movements, choose F2. 8,1/1000 seconds; In order to make the biggest depth of field, choose F22, 1/15 seconds.
"The exposure is equal in the above-mentioned every kind of associations, because any change of the shutter speed is changed and compensated by the corresponding diaphragm: 1/ It is 1/ 4 of second for 1/ 125 in 500 seconds, and F4 is 4 times that of F8, so as to analogize. This principle is called exposing the law equivalently, that is to say that is often misused ' pour the law of exchanging '. "
Irwin still points out then: "Must understand, it is appropriate shutter speed and combination of diaphragm that the correct one is exposed. This is that diaphragm has priority, the shutter speed has priority and all of different procedure types is exposed the basic principle behind the mode automatically too, expose the freedom that can offer choice manually. "
British photographer John and Willmot thinks: "Generally speaking, it is a kind of compromise method that various are exposed, but the part most important to the image is exposed correctly, can often improve the quality of the photo greatly. "
Willmot points out, while usually photographing, " no matter walk close to the light of body examination taken a photograph of, use and click examining to only express, can make sure to be exposed according to the shade or strong light, thus produced different results. Want, want, judge until which of image a portion go on, expose, need sharp eyes and experience accurate " .
Expose according to the strong light part, will make the bright part demonstrate the detail, but the shaded area will be very dark even become very dark, the whole photo will seem under-expose. For example sunshine shine upon at sea surface, what diaphragm part this difference kind than prospect at luminance. At this moment, expose, may make prospect to be under-expose according to panorama, and sunshine that majority glitter at surface of water know loss shed too. Will stress all those small luminous points to expose while reducing, facilitate displaying the detail of the sky. In this way the prospect will become a little darker, but will add the whole result. Willmot thinks, the appropriate reduction is exposed, make very good result sometimes. For example shoot the white statue with tree as backdrop, it is appropriate to adopt and expose equally, but if reduce the first class diaphragm, will make the bright object really stand out from darker background.
Sometimes, one simple scenery too probably because bright sky influence reading only expressed to examine, make time for exposure too short and destroying the result. Willmot think the problem very apt to solve, method to let scene of camera down examine all. When have very bright parts in the picture, for example bright building, seabeach, surface of water or dark body taken a photograph of are in the light-colored background, photos that is generally taken are all too dark. In order to obtain a kind of result that can be accepted, it is necessary to try hard to get rid of the most bright part while examining the light.
Willmot thinks, can also be exposed to make the picture adjust different shadows through controlling. Lofty tone can add picture graceful slim and graceful, but low-key to may bring dramatic result and heavy atmosphere. The high-profile illumination should be quite even, in order to avoid the shade, and the exposure used should make the details as many as possible in the bright part, this one that usually means is over-exposed. The ones that shot the low-key photo in order to use the sidelight result better, easy to cause a small amount of strong light part and are under-expose.
As for the colored density of the photo, can get obvious improvement through adjusting exposing too generally. To colored negative, the outstanding density can be through exposing accurately or obtaining the scenery over-exposedly. Often can make color turn into dust and dull, but over-exposed and apt to make color to be too dark to turn pale while being under-expose. Colored reversal film is as a same reason too, but contrary to this, under-expose half a shelf may make color thicken and more bright-colored.
British photographer T Woodcock has recommended handling the high contrast and is taken a photograph of the body, especially the one that is shone by the strong sidelight is taken a photograph of the skill of the body, its key is to try to measure supreme reading and the minimum reading. Examine and fetch the position of strong light and reading of the shade position separately at first, examining should pay attention to letting the strong light or shade position take and examine all range while fetching, then exposed according to the number value between two pieces of reading. For example: Strong light position reading: 1/ 500 seconds, F8; The position reading of the shade: 1/ 30 seconds, F8 exposes number value: 1/ 125 seconds, F8.
If mainly taken a photograph of the body too small, and much darker or much brighter than the background, must pay attention to examining and be unable to receive the excessive influence of the background while fetching reading. The method is to walk close to the body taken a photograph of or use the long shot to examine the light. The number value measured like this, is usually called " the key " Reading. If the body taken a photograph of is sports or difficult to be close to, a feasible method is to measure the reading of the substituent. The most convenient and commonly used method, examine the reading of fetching one's own back of the hand.
Woodcock thinks, the lighting question of the backlight should be a too big kind of contrast. While shooting this kind of scenery, the simplest method is to revitalize the picture, don't let the light source appear in the picture, and guarantee that there is not glare on the lens, then measure reading, the composition again, half a exposure is exposed to increase one and a half to two shelves. The method that another one is more accurate is, remember the normal mere reading of reflection, then examine and fetch from one's own back of the hand; A reading substituted, is exposed according to the middle value of these two pieces of reading.
Woodcock has also summarized correct several key ses exposed of reaching
1.Before examining the reading of fetching, see whether can estimate correctly that is exposed by oneself at first.
2. Pay attention to saving the battery at ordinary times. If find that examined and only expressed and has not worked and forgot to take the battery, adjust the shutter speed in the reciprocal of film sensitivity ISO value, for example the film is 1S0100/ 21. ,Adjust, have in 1/ 100 second shutter speed, fine to take a picture, the reversal film uses F16, the negative uses F11.
3.The candle only can be influenced and examined and only expressed seriously, should hide the light for the lens appropriately.
4.Can try to regard long shot as some types and examine 11 to only express and use.
5.While examining and only expressing and can't reveal reading under the dark and weak light, can rotate the film sensitivity index plate, improve ISO value, until examine and only express the reading of demonstrating. Then increase the exposing value, for example hold the great diaphragm. Sensitivity ISO value is improved by one time each time, diaphragm should open great first grade.
6.While using ultra wide-angle lens to take a picture, must examine the light with the standard lens first, then change ultra wide-angle lens to shoot.
7.Use the reversal film under the dim light, should under-expose half a shelf to first shelf, in order to keep the color saturation.
Canada famous photography artist and concurrently photograph, write Patterson, Furiman of writer, point out, begin to learn cameraman " study correct route that expose, to want, study tone to take a photograph of the body carefully, expect to make the correct judgement under various situations at one glance. Must be good at distinguishing what result it is higher or supports one, two, three shelves than ' the luminance on average ' of the composition, this needs to practise repeatedly. May not necessarily master skillfully even after a large number of practices, but always can help you to understand that examine the instruction that is only expressed, and understand that just reaches correct first step exposed. "
He says: "If you can recognize, take a photograph of into body different reflecting light amount of position or receive the light quantity accurately, then, you may vary scene or diaphragm, make it can embody you to feeling to take a photograph of the body not to expose. "
In a word, to taking a photograph of the exposing correctly of body, depend on the subjective factor, depend on the objective factor too. Should learn how to discern or estimate the tone or contrast of the body taken a photograph of, then according to examining the data that are only expressed, adjust shutter and diaphragm appropriately again, add the tone bright or reduce darkly, thus the result of exposing expected. The photographer needs to choose at moment, and the correct choice depends on thinking and practising.