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كتاب التصوير الفوتوغرافي المغلق
Macro lenses
Macro lenses with a focal length of 50mm or 55mm are the most popular of all macro lenses . Their optics are designed to provide the best definition at close range and they usually focus down to half life - size without any additional extension . With a maximum aperture of f2.8 or f3.5 , the are not as fast as a standard lens of the same focal length . However , since they are designed principally for close - up work , this is not a limiting factor because the lens will be stopped down as much as possible to achieve the maximum depth of field . It is for this reason that these macro lenses usually have a mini mum aperture of f32 - one step greater than f22 of the equivalent standard lens .
The front lens element of the 55mm micro Nikkor lens is so well recessed that there is no need to use a separate lens hood . This was the first lens I bought with my original Nikon and I use it more than any of my 13 other lenses for this system . Although it is used primarily for close - ups of static natural history subjects , I also use it for document and slide copying .
The design of both the 55mm micro - Nikkor f2.8 and the 50mm Zuiko Auto - macro f3.5 allows the whole rear part of the lens to move in and out as the lens is focused , thus enhanc ing the image quality at close - up ranges and still allowing a good definition at infinity .
Camera circuitry
I removed the top from an SLR camera to take this picture of part of the electronic circuitry . Only when you see the array of colored wires and components do you appreciate the complexity of the cameras which are the essential tools of the modern photographer . I lit this picture using a pair of fiber optics directed in at a low angle from each side . Lens 55mm micro - Nikkor Mag . on film × 1 Mag . on page × 6
There are also the so - called " true " macro lenses ( see p . 148 ) which cannot be focused and have to be used with bellows . They give very high definition at magnifications of up to 20 times life - size .
Polished petrified wood
Within Arizona's Petrified Forest National Park lie huge stone tree trunks . These spectacular plant fossils were formed after the fallen trees were covered by layers of mud and volcanic ash which prevented their decay by eliminating the oxygen supply . As silica - rich waters permeated through the ground , the wood was slowly replaced with silica and so became petrified . Collection of any petrified wood inside the park boundary is prohibited . Dealers do , however , collect elsewhere and this picture shows a portion of a polished section which I bought . It was taken inside by indirect available light . The range of colors originate from minerals which are deposited at the time the wood was turning to stone . Lens 55mm micro - Nikkor Mag . on film × 0.5 Mag . on page × 3
التشريح عن قرب ..
كتاب التصوير الفوتوغرافي المغلق
Macro lenses
Macro lenses with a focal length of 50mm or 55mm are the most popular of all macro lenses . Their optics are designed to provide the best definition at close range and they usually focus down to half life - size without any additional extension . With a maximum aperture of f2.8 or f3.5 , the are not as fast as a standard lens of the same focal length . However , since they are designed principally for close - up work , this is not a limiting factor because the lens will be stopped down as much as possible to achieve the maximum depth of field . It is for this reason that these macro lenses usually have a mini mum aperture of f32 - one step greater than f22 of the equivalent standard lens .
The front lens element of the 55mm micro Nikkor lens is so well recessed that there is no need to use a separate lens hood . This was the first lens I bought with my original Nikon and I use it more than any of my 13 other lenses for this system . Although it is used primarily for close - ups of static natural history subjects , I also use it for document and slide copying .
The design of both the 55mm micro - Nikkor f2.8 and the 50mm Zuiko Auto - macro f3.5 allows the whole rear part of the lens to move in and out as the lens is focused , thus enhanc ing the image quality at close - up ranges and still allowing a good definition at infinity .
Camera circuitry
I removed the top from an SLR camera to take this picture of part of the electronic circuitry . Only when you see the array of colored wires and components do you appreciate the complexity of the cameras which are the essential tools of the modern photographer . I lit this picture using a pair of fiber optics directed in at a low angle from each side . Lens 55mm micro - Nikkor Mag . on film × 1 Mag . on page × 6
There are also the so - called " true " macro lenses ( see p . 148 ) which cannot be focused and have to be used with bellows . They give very high definition at magnifications of up to 20 times life - size .
Polished petrified wood
Within Arizona's Petrified Forest National Park lie huge stone tree trunks . These spectacular plant fossils were formed after the fallen trees were covered by layers of mud and volcanic ash which prevented their decay by eliminating the oxygen supply . As silica - rich waters permeated through the ground , the wood was slowly replaced with silica and so became petrified . Collection of any petrified wood inside the park boundary is prohibited . Dealers do , however , collect elsewhere and this picture shows a portion of a polished section which I bought . It was taken inside by indirect available light . The range of colors originate from minerals which are deposited at the time the wood was turning to stone . Lens 55mm micro - Nikkor Mag . on film × 0.5 Mag . on page × 3
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