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الكاميرات والعدسات .. المعدات الأساسية .. كيفية التقاط وتطوير الصور الملونة
ESSENTIAL EQUIPMENT
CAMERAS & LENSES
Lenses vary in the quality of their manufacture and the maximum aperture ( often referred to as the ' speed ' of a lens : f / 1.4 is fast for a standard lens , f / 2.8 quite slow ) . Still , the most important difference is the focal length . Think in terms of what would be the ideal range for you and your preferred subjects . The more extreme the focal length on either side of the standard 50mm , the more exaggerated the effect on the image , and the more expensive the lens . Personal taste is the only guide to follow , but the high sales of wide - angle lenses of around 28mm focal length , and of telephoto lenses around 135mm , show what the majority of people tend to choose .
Apart from focal length , other important distinctions among lenses involve special uses . Most of these , by definition , fall outside the category of basic equipment but one is sufficiently popular to consider here . A macro lens has the ability to focus closely and give magnified views of small subjects , generally up to half life - size ( normal lenses do not focus down so closely , giving a maxi- mum enlargement of around one - seventh life - size ) . The optical quality of a macro lens at these close - focusing distances is , of course , high , but as this kind of lens also does a good job at normal distances , many photographers make it double up as their standard lens . Many zoom lenses have a ' macro ' facility .
Angles of View
Compare the 62 ° angle of view of a 35mm wideangle ( 1 ) with the 46 ° of a 55mm standard lens ( 2 ) and the even narrower view offered by a 180mm telephoto ( 3 ) .
Wide - Angle Lens
Wide angle lens . The 24mm lens ( LEFT ) . with an angle of view of 84 degrees , uses a retrofocus design to lengthen its extremely short focus so that it can be used with the reflex mirror in the camera housing . To overcome the problem of poor image quality at close focusing , the elements float ' inside the housing . Their relative positions can therefore be changed as the lens focuses closer . In use ( ABOVE RIGHT ) , depth of field is relatively large while perspective is greatly exaggerated .
Standard Lens
Standard lens . This 50mm standard lens presents the world approximately as the human eye sees it , giving a 46 degree angle of view that gives a ' natural ' perspective and a moderately wide minimum aperture of 12 ( although f1.8 maximum aperture are by far the most common on today's
50mm standards ) . Its six elements in four groups allow the manufacturer design flexibility to correct most common aberrations . In use ( ABOVE RIGHT ) , the lens proves an ideal all - rounder , with its relatively fast maximum aperture allowing the photographer to work in low - light conditions .
Long - Focus Lens
Long - focus lens . A favourite among many photo- journalists , this fast 180mm telephoto lens has a maximum aperture of f2.8 , which makes it fairly easy to hand - hold at quite slow speeds . For colour work in poor lighting conditions it is an ideal
telephoto . Many lenses of this focal length tend to be heavy for their size , but this can be an advantage , as they lie steady in the hand . In use ( RIGHT ) , perspective is compressed while focusing can be quite critical .
ESSENTIAL EQUIPMENT
CAMERAS & LENSES
Lenses vary in the quality of their manufacture and the maximum aperture ( often referred to as the ' speed ' of a lens : f / 1.4 is fast for a standard lens , f / 2.8 quite slow ) . Still , the most important difference is the focal length . Think in terms of what would be the ideal range for you and your preferred subjects . The more extreme the focal length on either side of the standard 50mm , the more exaggerated the effect on the image , and the more expensive the lens . Personal taste is the only guide to follow , but the high sales of wide - angle lenses of around 28mm focal length , and of telephoto lenses around 135mm , show what the majority of people tend to choose .
Apart from focal length , other important distinctions among lenses involve special uses . Most of these , by definition , fall outside the category of basic equipment but one is sufficiently popular to consider here . A macro lens has the ability to focus closely and give magnified views of small subjects , generally up to half life - size ( normal lenses do not focus down so closely , giving a maxi- mum enlargement of around one - seventh life - size ) . The optical quality of a macro lens at these close - focusing distances is , of course , high , but as this kind of lens also does a good job at normal distances , many photographers make it double up as their standard lens . Many zoom lenses have a ' macro ' facility .
Angles of View
Compare the 62 ° angle of view of a 35mm wideangle ( 1 ) with the 46 ° of a 55mm standard lens ( 2 ) and the even narrower view offered by a 180mm telephoto ( 3 ) .
Wide - Angle Lens
Wide angle lens . The 24mm lens ( LEFT ) . with an angle of view of 84 degrees , uses a retrofocus design to lengthen its extremely short focus so that it can be used with the reflex mirror in the camera housing . To overcome the problem of poor image quality at close focusing , the elements float ' inside the housing . Their relative positions can therefore be changed as the lens focuses closer . In use ( ABOVE RIGHT ) , depth of field is relatively large while perspective is greatly exaggerated .
Standard Lens
Standard lens . This 50mm standard lens presents the world approximately as the human eye sees it , giving a 46 degree angle of view that gives a ' natural ' perspective and a moderately wide minimum aperture of 12 ( although f1.8 maximum aperture are by far the most common on today's
50mm standards ) . Its six elements in four groups allow the manufacturer design flexibility to correct most common aberrations . In use ( ABOVE RIGHT ) , the lens proves an ideal all - rounder , with its relatively fast maximum aperture allowing the photographer to work in low - light conditions .
Long - Focus Lens
Long - focus lens . A favourite among many photo- journalists , this fast 180mm telephoto lens has a maximum aperture of f2.8 , which makes it fairly easy to hand - hold at quite slow speeds . For colour work in poor lighting conditions it is an ideal
telephoto . Many lenses of this focal length tend to be heavy for their size , but this can be an advantage , as they lie steady in the hand . In use ( RIGHT ) , perspective is compressed while focusing can be quite critical .
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