تويت
التصوير الفوتوغرافي الحديث
تحديد الوضع الصحيح ..
التعرض لظروف غير عادية ..
EXPOSURE FOR UNUSUAL CONDITIONS HIGH ALTITUDES
At high altitudes , the air is quite clear because it contains very little dust to reflect light into the shadows . They will , therefore , go noticeably darker than similar shadows at low altitudes . Even tho the shadows are darker , longer exposures are usually not practical because the highlights are also brighter than normal . The best method for black - and - white film is to control contrast by reducing development time slightly . This subject is discussed more fully in a later Assignment .
SUNSETS AND SILHOUETTES
Aim the meter directly at the brightest area of the subject , such as the sky in a sunset , and use the exposure called for by the main arrow . This will greatly underexpose all shadow areas , giving the desired sunset effect . The picture in Figure 11 was exposed in this way .
Fig . 11 Deep sunset effect was obtained by aiming meter directly at sky and exposing for sunset itself .
Fig . 12 To arrive at best exposure for back - lighted scene , meter was aimed at water but shaded from direct rays of sun .
BACKLIGHTED SUBJECTS
With a back - lighted subject , the source of light , such as the sun , is facing the photographer . If he takes an exposure reading in the usual way , the strength of the direct light falling on the exposure meter will cause it to read much too high . It is , therefore , necessary to shade the meter while you are taking a reading of the subject in order to keep the direct rays of the sun out of the meter . In Figure 12 , the meter was aimed at the water in the foreground , but it was shaded to keep out the sunlight .
In In photographing a back - lighted subject , the photographer must often decide . whether to expose for the shadow area or for the area of greatest illuminati Figure 12 , the exposure was for the area of greatest illumination , which is the water . In Figure 13 , the film was exposed for the shadow area , which was the building in the background and the back of the statue . The sunlit area is represented only by a barely perceptible line of highlight along the left side of the statue in the foreground . In Figure 14 , the exposure was for this highlight area .
Note the greatly increased dramatic effect . This treatment is often successful where detail is not particularly important , but where mood is to be stressed .
AERIAL PICTURES
Aim the meter downward to prevent a false reading from the bright sky . As a general rule at altitudes below 1000 feet , expose according to the meter reading ; from 1000 to 2000 feet , stop down 1/3 stop ; from 2000 to 4000 feet , close down 1/2 stop ; above 4000 feet , close down one full stop .
OVERCAST SCENES
In such scenes , contrast is quite low , since there are no strong shadows nor strong highlights . Black - and - white pictures can usually be improved by giving half the indicated exposure , provided you increase development time by 10 to 25 percent to increase contrast . If it is not practical to modify development , stick to the indicated exposure .
AVAILABLE LIGHT PHOTOGRAPHY
If the illumination level is too low to get an accurate reading in the normal manner , take a close - up reading from the brightest object in the scene . If no bright object is available or convenient , take a reading from a sheet of white paper or a handkerchief located in a representative part of the scene . Read the exposure from the O arrow on your meter . If your meter does not have an O arrow ,
Fig . 13 Meter was aimed directly at building and statue , both of which were in shadow . They are there fore reproduced with good detail .
Fig . 14 Same subject as Fig . 13 , but meter reading was taken by aiming at front of statue which was in direct sunlight . This emphasized intense highlighting along side of statue and permitted everything else to go into deep shadow .
Fig . 15 Because of low level of illumination , meter reading was taken from a white handkerchief held in area of maximum illumination and lens then opened three stops beyond indicated exposure .
read the main exposure pointer , and open the lens three additional stops . The exposure in Figure 15 was determined in this manner .
تحديد الوضع الصحيح ..
التعرض لظروف غير عادية ..
EXPOSURE FOR UNUSUAL CONDITIONS HIGH ALTITUDES
At high altitudes , the air is quite clear because it contains very little dust to reflect light into the shadows . They will , therefore , go noticeably darker than similar shadows at low altitudes . Even tho the shadows are darker , longer exposures are usually not practical because the highlights are also brighter than normal . The best method for black - and - white film is to control contrast by reducing development time slightly . This subject is discussed more fully in a later Assignment .
SUNSETS AND SILHOUETTES
Aim the meter directly at the brightest area of the subject , such as the sky in a sunset , and use the exposure called for by the main arrow . This will greatly underexpose all shadow areas , giving the desired sunset effect . The picture in Figure 11 was exposed in this way .
Fig . 11 Deep sunset effect was obtained by aiming meter directly at sky and exposing for sunset itself .
Fig . 12 To arrive at best exposure for back - lighted scene , meter was aimed at water but shaded from direct rays of sun .
BACKLIGHTED SUBJECTS
With a back - lighted subject , the source of light , such as the sun , is facing the photographer . If he takes an exposure reading in the usual way , the strength of the direct light falling on the exposure meter will cause it to read much too high . It is , therefore , necessary to shade the meter while you are taking a reading of the subject in order to keep the direct rays of the sun out of the meter . In Figure 12 , the meter was aimed at the water in the foreground , but it was shaded to keep out the sunlight .
In In photographing a back - lighted subject , the photographer must often decide . whether to expose for the shadow area or for the area of greatest illuminati Figure 12 , the exposure was for the area of greatest illumination , which is the water . In Figure 13 , the film was exposed for the shadow area , which was the building in the background and the back of the statue . The sunlit area is represented only by a barely perceptible line of highlight along the left side of the statue in the foreground . In Figure 14 , the exposure was for this highlight area .
Note the greatly increased dramatic effect . This treatment is often successful where detail is not particularly important , but where mood is to be stressed .
AERIAL PICTURES
Aim the meter downward to prevent a false reading from the bright sky . As a general rule at altitudes below 1000 feet , expose according to the meter reading ; from 1000 to 2000 feet , stop down 1/3 stop ; from 2000 to 4000 feet , close down 1/2 stop ; above 4000 feet , close down one full stop .
OVERCAST SCENES
In such scenes , contrast is quite low , since there are no strong shadows nor strong highlights . Black - and - white pictures can usually be improved by giving half the indicated exposure , provided you increase development time by 10 to 25 percent to increase contrast . If it is not practical to modify development , stick to the indicated exposure .
AVAILABLE LIGHT PHOTOGRAPHY
If the illumination level is too low to get an accurate reading in the normal manner , take a close - up reading from the brightest object in the scene . If no bright object is available or convenient , take a reading from a sheet of white paper or a handkerchief located in a representative part of the scene . Read the exposure from the O arrow on your meter . If your meter does not have an O arrow ,
Fig . 13 Meter was aimed directly at building and statue , both of which were in shadow . They are there fore reproduced with good detail .
Fig . 14 Same subject as Fig . 13 , but meter reading was taken by aiming at front of statue which was in direct sunlight . This emphasized intense highlighting along side of statue and permitted everything else to go into deep shadow .
Fig . 15 Because of low level of illumination , meter reading was taken from a white handkerchief held in area of maximum illumination and lens then opened three stops beyond indicated exposure .
read the main exposure pointer , and open the lens three additional stops . The exposure in Figure 15 was determined in this manner .
تعليق