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السُحب .. مصدر الضوء .. كيفية التقاط وتطوير الصور بالأبيض والأسود
CLOUDS
Clouds alter the quality of sunlight by diffusing it , and also play an important role as components in a landscape . The extent to which they soften the light and reduce shadows depends on how thick the cloud cover is and on how high So , a shroud of low , dense cloud diffuses light over the entire sky , to the extent that a completely overcast day there are no outdoor shadows at all , and it may be impossible even to see the direction of the sun . Thin , high cloud , on the other hand , just takes the edge off shadows and highlights , and can help , for instance , in a very slight softening of a portrait .
As well as diffusing sunlight , cloud cover also reduces the amount , and this has an obvious effect on the exposure settings for the camera . As a rule of thumb , thin , high cloud can reduce the light level on the ground by up to one stop , a bright cloudy day has about a two - stop effect , moderately overcast about three stops , and strongly overcast ( stormy ) about four stops .
Although cloudy weather reduces local contrast by making the light more enveloping and weakening shadows , in a broad landscape it can actually in-
crease the contrast between land and sky . There may be a modest difference in brightness between green fields and a blue sky , but it can reach up to five or six stops between the same landscape and a bright , overcast sky . In this kind of view , it can help either to use a neutral graduated filter or to give the sky extra exposure when making the print .
Clouds of different types and shapes can also make imposing parts of a landscape , and can even be dominant enough to make the main subject of a photograph . The most useful in this way , to be included as part of the composi- tion , are those with distinct , precise shapes - fluffy cumulus , cirrus , or the anvil - shape of a thunderhead - and those with sharp tonal contrast .
In order to make the most of interesting clouds , it helps to use a wide - angle lens ( to take in a broad sweep of the sky ) and to place the horizon close to the bottom of the frame . Also , if the sun is more or less at right angles to the camera view , a polarizing filter will emphasise the contrast with the blue areas of the sky . The most useful filters of all for black - and - white photography , however , are yellow , orange and red , which darken the entire blue of the sky to differing degrees .
LEFT Clouds can be so striking that they demand to be made the dominant part of the composition . Best suited are clouds with strong distinct shapes .
ABOVE Low cloud on hilltops can soften light beautifully , providing the photographer with the perfect opportunity to exploit the naturally strong texture of the landscape .
RIGHT A shroud of low , dense cloud diffuses light over the entire sky , occasionally to the extent where shadows disappear altogether .
CLOUDS
Clouds alter the quality of sunlight by diffusing it , and also play an important role as components in a landscape . The extent to which they soften the light and reduce shadows depends on how thick the cloud cover is and on how high So , a shroud of low , dense cloud diffuses light over the entire sky , to the extent that a completely overcast day there are no outdoor shadows at all , and it may be impossible even to see the direction of the sun . Thin , high cloud , on the other hand , just takes the edge off shadows and highlights , and can help , for instance , in a very slight softening of a portrait .
As well as diffusing sunlight , cloud cover also reduces the amount , and this has an obvious effect on the exposure settings for the camera . As a rule of thumb , thin , high cloud can reduce the light level on the ground by up to one stop , a bright cloudy day has about a two - stop effect , moderately overcast about three stops , and strongly overcast ( stormy ) about four stops .
Although cloudy weather reduces local contrast by making the light more enveloping and weakening shadows , in a broad landscape it can actually in-
crease the contrast between land and sky . There may be a modest difference in brightness between green fields and a blue sky , but it can reach up to five or six stops between the same landscape and a bright , overcast sky . In this kind of view , it can help either to use a neutral graduated filter or to give the sky extra exposure when making the print .
Clouds of different types and shapes can also make imposing parts of a landscape , and can even be dominant enough to make the main subject of a photograph . The most useful in this way , to be included as part of the composi- tion , are those with distinct , precise shapes - fluffy cumulus , cirrus , or the anvil - shape of a thunderhead - and those with sharp tonal contrast .
In order to make the most of interesting clouds , it helps to use a wide - angle lens ( to take in a broad sweep of the sky ) and to place the horizon close to the bottom of the frame . Also , if the sun is more or less at right angles to the camera view , a polarizing filter will emphasise the contrast with the blue areas of the sky . The most useful filters of all for black - and - white photography , however , are yellow , orange and red , which darken the entire blue of the sky to differing degrees .
LEFT Clouds can be so striking that they demand to be made the dominant part of the composition . Best suited are clouds with strong distinct shapes .
ABOVE Low cloud on hilltops can soften light beautifully , providing the photographer with the perfect opportunity to exploit the naturally strong texture of the landscape .
RIGHT A shroud of low , dense cloud diffuses light over the entire sky , occasionally to the extent where shadows disappear altogether .
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