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معدات وتقنيات إضافية .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
FURTHER EQUIPMENT AND TECHNIQUES
STEP 1 : Additional lenses
STEP 2 : Filters
STEP 3 : Close - up attachments
STEP 4 : Exposure control
STEP 5 : Artificial lighting
STEP 6 : Advanced picture building
This section presents more advanced camera equipment and techniques with which you can extend your range of photography . Up until now you have been working with a camera with a normal lens , using straightforward natural lighting . Here you will be exploring the visual possibilities of lenses with different focal lengths , specialist lenses , filters , and close - up attachments . Next you will be introduced to controlled exposure techniques . These enable you to cope with difficult existing light situations , or to determine the tonal range in a photograph . This leads on to the principles and equipment involved in lighting with studio lamps and flash . Lastly the section develops further picture building aspects which arise from your extra equipment and knowledge .
Before tackling anything in this section you must have worked through the Camera Technique section , ( pp . 23-44 ) and preferably the first Picture Building section too . ( pp . 45-64 ) . These two sections provide you with the experience and knowledge of camera stills and composition necessary for this part of the book . You don't have to know how to process and print your film , however , because all advanced aspects of darkroom work have been collected into the section which follows this one .
Organisation of the section
Most topics in this section relate equally to black and white and color photography ( except the filters shown on page 100 , which apply to black and white photography only ) . However , before trying any of these techniques in color , you should first work through the Color Photography section ( pp . 141-58 ) . There are many factors particular to color photography you should know about , since they will affect your results . Before working on the lens aspects of this section , you may find it helpful to re - read the basic principles of image - forming , seeing , and photography on pages 16-17 and pages 20-1 .
It is not necessary to work through the steps in this section sequentially . Each one is a separate topic , so you may want merely to dip in to cover , say , wide - angle lenses , or filters . Which steps you choose to tackle will depend largely upon what equipment you possess or are intending to buy . Reading through this section will give you a good idea of whether certain items are worth acquiring or not .
Much depends on what type of photography you are interested in doing . Working with a moderate range of lenses can be useful in a variety of situations . But you are unlikely to use the very long and short focal length types so often , because the images they give are so extreme . Often you can hire these lenses for unusual jobs - or you may buy a particular lens to suit your special interests , for example a telephoto lens for wildlife photography . Close - up attachments are also much used for natural history photography - as well as for copying stamps , coins , and similar collectors ' items .
Understanding how to use studio spot and flood lighting is essential for still - life pictures , commercial work , and formal portraiture . On the other hand , if you are more interested in action shots , documentary pictures , and location work where you must carry lighting around , then flash may be the more practical lighting technique .
The Steps concerning controlled exposure techniques and further picture building skills apply to whatever type of photography you undertake . Working through them will lead you on to developing your own personal style .
As always , the best way to learn and absorb the material here is to practice - even though , in this case , you may have to borrow items of equipment you don't yet possess . Incidentally , if you are making your own comparisons between different lenses , attachments , and light arrangements , it will be helpful to have a tripod to support your camera . With a tripod you can keep the camera viewpoint identical or carefully control any changes through a series of shots so that differences created by the items you are trying out can be isolated .
Using lenses
The first Step looks at the advantages of having additional lenses for your camera . Lens interchangeability is one of the great features of the single lens reflex camera . Remember , it has a focal plane shutter in front of the film so you can remove and replace lenses at any time without fogging the film . This camera also always shows the image " seen " by the lens on the focusing screen . A few expensive direct viewfinder cameras with focal plane shutters also allow lens changing , and either have marks in the viewfinder to show how much of the scene you will record with each type of lens , or have coupled rangefinders that change according to the lens fitted . But the range of lenses is limited compared with the great number of lenses available for SLR cameras . This is because it would be impossible , for example , to indicate the angle of view of a fisheye wide - angle lens on a direct vision camera . Some twin lens reflex cameras accept different focal length lenses , but here too the range is limited , and expense is also restricting as you have to buy a pair of lenses for every new focal length ( see p . 205 ) .
Unfortunately most makes of interchangeable lens camera are designed with their own exclusive method of lens attachment . Some accept screw - in lenses ; others half - turn ( bayonet ) lenses . Each is usually incompatible with other makes . This means that you are encouraged to buy from the camera manufacturer's range of lenses , and it is arguable that these lenses will give the best optical quality with the cameras they are built to complement . But the range and price of these lenses are factors you should consider when you are first deciding which camera to buy . However , there are manufacturers who only make lenses . These fit various makes of camera either by copying the thread size on the mount , or by adaptor rings . The advantage of these lenses is that you may not have to change them if you change your camera model .
If your camera has a fixed lens , it may be still possible to use different focal lengths , by adding a convertor lens attachment . In this case you may be able either to adapt the viewfinder , or fit an extra one into the camera accessory shoe .
You will see that lenses divide into two groups : a basic set of three - moderately wide - angle , normal , and moderately long focal lengths - and a variety of special types . Most photographers will agree that the basic set is well worth acquiring , because it can be used in so many ways . Which actual focal lengths you choose however is a much more personal decision . The wide- angle and long focus lenses shown here are 28 mm and 135 mm respectively . But you may prefer , say , a 35 mm wide - angle and a 200 mm long focus lens . These focal lengths apply only to a 35 mm camera ( 24 x 36 mm format ) . The equivalents to 28 mm and 135 mm for a 24 ins square camera would be about 50 mm and 250 mm . because everything is scaled up proportionally . In fact , all focal lengths given throughout this section relate to a 35 mm size camera . So if you are using a 24 ins format camera , multiply quoted focal lengths by just under two times . The more unusual lenses have specialist applications . Some , like the shift lens . are useful in architectural and still - life photography . Extreme telephoto ( or the less bulky , mirror long focus ) lenses give effects like photographing through telescopes . They can pick out detail at very long distances . Extreme wide - angles allow you to include almost a whole room in your picture , while the fisheye version gives weirdly distorted shapes .
Modern lens optics
All these lenses are made to various standards of optics , which are generally indicated by their price . A cheaper lens may sound a bargain , but test it out first at various distances , photographing a finely detailed subject such as a newspaper . Then check image resolution on the negative with a magnifier . Good quality lenses may seem very expensive , but this is the result of solving extremely complex design problems and precision assembly of the various glass elements .
Before the 1960s , most of today's extreme lens types were impossible to make . Advanced digital computers are necessary to test proposed lens designs . They predict the paths of hundreds of light rays through the lens element to each part of the picture area . From the results , the computer builds up profiles of lens elements of the right shape and glass type , so that when combined in a compound lens they will counteract each other's aberrations ( optical errors ) .
Extremely efficient optical glass materials have been developed in Germany and Japan . They have strong refractive index ( light bending power ) but do not appreciably disperse white light into its component colors ( see pp . 16 , 148 ) . It is such types of glass which have made modern lenses so accurate for color work in particular . These glasses are ground and polished into highly accurate shapes , which are able to fit together , and strong enough to stand up to wear . Optical engineers have to devise lens barrels which will hold up to twenty separate elements per lens , accurately aligned and spaced , which will not be affected by the air temperature around them .
Each glass surface is coated with several thin films of transparent material to minimize internal light reflections . Without this " blooming " , reflections from the dozens of air - to- glass surfaces would give a gray , flat image , like looking through a number of windows . Look into a good quality modern lens , and you will often see the slight yellow or purple " bloom " reflected from the outer coating of its top surface . Turn the lens around and look through it , and this color disappears . Coated lenses are not only essential for modern multi - element designs , they also greatly reduce light flare when you are photographing toward a bright light source . If you buy a secondhand lens made in the 1950s before they were all coated , you will see its notably poorer performance under these conditions .
This also explains why you must take such care when cleaning the camera lens , see page 211. If you wipe it with an ordinary cloth you may scratch the coating layer or the relatively soft optical glass beneath . A lens damaged in this way may scatter light , giving you a grayer , less brilliant image . Similarly , dropping your lens may not appear to create much damage but it can misalign some of the glass components , and so seriously upset image quality .
Using lens attachments and filters
Camera lenses have to be designed for a known set of working conditions - say for subject distances ranging from infinity down to two or three feet . So each lens has a near focusing limit . Attachments such as rings or bellows enable you to focus nearer subjects , but the lens is not then performing under its intended conditions and image definition may be slightly poorer . Perhaps the corners will look less sharp than the image center . Close - up rings and bellows are difficult to use on a viewfinder camera because you cannot see what is in focus . Some solutions to these problems are discussed in the third Step , showing lens attachments . The previous Step covers color filters for black and white photography . Before working with these you should look forward to the details on complementary colors on pages 148 and 160-1 . They explain unfamiliar color names , such as magenta and cyan , and shows how primary and com- plementary ( opposite ) colors relate to each other .
Unlike lenses , filters will fit on any camera , provided they match the lens diameter . But if you work much with filters , you will find it easiest to use a single lens reflex camera with " through - the - lens " metering . A filter over the lens reduces light reaching the film as well as affecting the image . Through - the- lens meters will read the correct exposure , allowing for the filter ; while the reflex viewing will show you how the filter alters the picture tones . With viewfinder cameras you must calculate filter exposures , and judge the filtration effects , from information supplied with the filter pack - and your own experience .
Using exposure and lighting
Step four shows you how to solve particular exposure problems- with metering techniques which give greater accuracy in extreme conditions . Before reading this part , turn back and recap basic exposure metering on pages 39-43 . You are now dealing with more difficult indoor conditions , where lighting is weak and often contrasty too . Understanding the meter response can help you to judge exposure for particular effects , or aim for an ideal tone value for the most important part of your picture . Choice of exposure can be a creative decision . Later you will learn how to follow it through in the darkroom by further control at the development stage ( see pp . 126-7 ) .
The next Step , on artificial lighting , is concerned more with the appearance of the subject than the technicalities of camera and film . If you are considering buying equipment , some of the points made here are again worth noting . If you are working in color , it is essential that you have read through pages 141-7 of the Color Photography section before starting this Step , because unlike black and white materials color films respond differently to different types of lighting .
There is a very close relationship between the quality and direction of natural daylight and the type and positioning of studio lamps or flash units . Before starting on this Step it will help you to check back to the pages in the Picture Building section on lighting ( pp . 50-3 ) , and revise your knowledge and understanding of light direction and quality .
Lighting is not just a technique to give enough illumination for convenient exposures . It is also a highly creative tool and fundamental to picture making . This applies particularly to flash , which is often just mounted on top of the camera so that every picture is lit in exactly the same way .
In the early days of flash lighting , photographers poured magnesium powder into trays and lit a slow touch paper or ignited it with sparks from a flint . The whole process was very dangerous , and the photographer had to open the shutter with one hand and fire the flash with the other . Later , magnesium foil was fitted into lampsize flashbulbs and fired by electricity . Press photographers of the 1930s used large flashbulb holders clamped to the side of their cameras .
Electronic flash units appeared after World War II , at first of very low efficiency . Since then both bulb and electronic units have steadily shrunk in size . Today the small flash cube or flash bar or " flip - flash " give several flashes before having to be changed . The electronic flash unit is often very little larger and gives several hundred low cost flashes . You can use both on long extension leads , away from the camera . Bigger , more powerful ( but more expensive ) units can be used in twos and threes instead of studio lamps . You must decide which will suit your use of flash best . Remember that the principles of lighting and the need for thought and care in picking and arranging lighting conditions apply equally to daylight , tungsten lamps , and flash lighting .
Using equipment creatively
The final pages of this section are a continuation from basic picture building . ( pp . 45-64 ) . Now however you can exploit the extra equipment which has been discussed . For example , linear perspective and lens focal length are closely related . So are aerial perspective and control of exposure and lighting . Learning to use both forms of perspective enables you to increase or suppress apparent depth in your pictures .
Lighting such as flash , and techniques such as camera panning and using the shallow depth of field given by long focus lenses , allow you to give emphasis to particular elements in your picture . Try some of these effects yourself - your experiments may encourage you to buy some of the equipment seen earlier .
By the end of this section you will see how each worthwhile piece of equipment or technique widens the range of images that you can put on to your film . None of them however are substitutes for ideas and imagination . They are all tools , which different photographers will choose to use in quite diverse ways , as some of the individual styles presented at the end of this book show . One of the dangers of photography is that the tools are so ingeniously and beautifully made that you may start to collect equipment instead of producing pictures . But it is your own ideas , and your interest in a particular subject or effect , that should come first .
FURTHER EQUIPMENT AND TECHNIQUES
STEP 1 : Additional lenses
STEP 2 : Filters
STEP 3 : Close - up attachments
STEP 4 : Exposure control
STEP 5 : Artificial lighting
STEP 6 : Advanced picture building
This section presents more advanced camera equipment and techniques with which you can extend your range of photography . Up until now you have been working with a camera with a normal lens , using straightforward natural lighting . Here you will be exploring the visual possibilities of lenses with different focal lengths , specialist lenses , filters , and close - up attachments . Next you will be introduced to controlled exposure techniques . These enable you to cope with difficult existing light situations , or to determine the tonal range in a photograph . This leads on to the principles and equipment involved in lighting with studio lamps and flash . Lastly the section develops further picture building aspects which arise from your extra equipment and knowledge .
Before tackling anything in this section you must have worked through the Camera Technique section , ( pp . 23-44 ) and preferably the first Picture Building section too . ( pp . 45-64 ) . These two sections provide you with the experience and knowledge of camera stills and composition necessary for this part of the book . You don't have to know how to process and print your film , however , because all advanced aspects of darkroom work have been collected into the section which follows this one .
Organisation of the section
Most topics in this section relate equally to black and white and color photography ( except the filters shown on page 100 , which apply to black and white photography only ) . However , before trying any of these techniques in color , you should first work through the Color Photography section ( pp . 141-58 ) . There are many factors particular to color photography you should know about , since they will affect your results . Before working on the lens aspects of this section , you may find it helpful to re - read the basic principles of image - forming , seeing , and photography on pages 16-17 and pages 20-1 .
It is not necessary to work through the steps in this section sequentially . Each one is a separate topic , so you may want merely to dip in to cover , say , wide - angle lenses , or filters . Which steps you choose to tackle will depend largely upon what equipment you possess or are intending to buy . Reading through this section will give you a good idea of whether certain items are worth acquiring or not .
Much depends on what type of photography you are interested in doing . Working with a moderate range of lenses can be useful in a variety of situations . But you are unlikely to use the very long and short focal length types so often , because the images they give are so extreme . Often you can hire these lenses for unusual jobs - or you may buy a particular lens to suit your special interests , for example a telephoto lens for wildlife photography . Close - up attachments are also much used for natural history photography - as well as for copying stamps , coins , and similar collectors ' items .
Understanding how to use studio spot and flood lighting is essential for still - life pictures , commercial work , and formal portraiture . On the other hand , if you are more interested in action shots , documentary pictures , and location work where you must carry lighting around , then flash may be the more practical lighting technique .
The Steps concerning controlled exposure techniques and further picture building skills apply to whatever type of photography you undertake . Working through them will lead you on to developing your own personal style .
As always , the best way to learn and absorb the material here is to practice - even though , in this case , you may have to borrow items of equipment you don't yet possess . Incidentally , if you are making your own comparisons between different lenses , attachments , and light arrangements , it will be helpful to have a tripod to support your camera . With a tripod you can keep the camera viewpoint identical or carefully control any changes through a series of shots so that differences created by the items you are trying out can be isolated .
Using lenses
The first Step looks at the advantages of having additional lenses for your camera . Lens interchangeability is one of the great features of the single lens reflex camera . Remember , it has a focal plane shutter in front of the film so you can remove and replace lenses at any time without fogging the film . This camera also always shows the image " seen " by the lens on the focusing screen . A few expensive direct viewfinder cameras with focal plane shutters also allow lens changing , and either have marks in the viewfinder to show how much of the scene you will record with each type of lens , or have coupled rangefinders that change according to the lens fitted . But the range of lenses is limited compared with the great number of lenses available for SLR cameras . This is because it would be impossible , for example , to indicate the angle of view of a fisheye wide - angle lens on a direct vision camera . Some twin lens reflex cameras accept different focal length lenses , but here too the range is limited , and expense is also restricting as you have to buy a pair of lenses for every new focal length ( see p . 205 ) .
Unfortunately most makes of interchangeable lens camera are designed with their own exclusive method of lens attachment . Some accept screw - in lenses ; others half - turn ( bayonet ) lenses . Each is usually incompatible with other makes . This means that you are encouraged to buy from the camera manufacturer's range of lenses , and it is arguable that these lenses will give the best optical quality with the cameras they are built to complement . But the range and price of these lenses are factors you should consider when you are first deciding which camera to buy . However , there are manufacturers who only make lenses . These fit various makes of camera either by copying the thread size on the mount , or by adaptor rings . The advantage of these lenses is that you may not have to change them if you change your camera model .
If your camera has a fixed lens , it may be still possible to use different focal lengths , by adding a convertor lens attachment . In this case you may be able either to adapt the viewfinder , or fit an extra one into the camera accessory shoe .
You will see that lenses divide into two groups : a basic set of three - moderately wide - angle , normal , and moderately long focal lengths - and a variety of special types . Most photographers will agree that the basic set is well worth acquiring , because it can be used in so many ways . Which actual focal lengths you choose however is a much more personal decision . The wide- angle and long focus lenses shown here are 28 mm and 135 mm respectively . But you may prefer , say , a 35 mm wide - angle and a 200 mm long focus lens . These focal lengths apply only to a 35 mm camera ( 24 x 36 mm format ) . The equivalents to 28 mm and 135 mm for a 24 ins square camera would be about 50 mm and 250 mm . because everything is scaled up proportionally . In fact , all focal lengths given throughout this section relate to a 35 mm size camera . So if you are using a 24 ins format camera , multiply quoted focal lengths by just under two times . The more unusual lenses have specialist applications . Some , like the shift lens . are useful in architectural and still - life photography . Extreme telephoto ( or the less bulky , mirror long focus ) lenses give effects like photographing through telescopes . They can pick out detail at very long distances . Extreme wide - angles allow you to include almost a whole room in your picture , while the fisheye version gives weirdly distorted shapes .
Modern lens optics
All these lenses are made to various standards of optics , which are generally indicated by their price . A cheaper lens may sound a bargain , but test it out first at various distances , photographing a finely detailed subject such as a newspaper . Then check image resolution on the negative with a magnifier . Good quality lenses may seem very expensive , but this is the result of solving extremely complex design problems and precision assembly of the various glass elements .
Before the 1960s , most of today's extreme lens types were impossible to make . Advanced digital computers are necessary to test proposed lens designs . They predict the paths of hundreds of light rays through the lens element to each part of the picture area . From the results , the computer builds up profiles of lens elements of the right shape and glass type , so that when combined in a compound lens they will counteract each other's aberrations ( optical errors ) .
Extremely efficient optical glass materials have been developed in Germany and Japan . They have strong refractive index ( light bending power ) but do not appreciably disperse white light into its component colors ( see pp . 16 , 148 ) . It is such types of glass which have made modern lenses so accurate for color work in particular . These glasses are ground and polished into highly accurate shapes , which are able to fit together , and strong enough to stand up to wear . Optical engineers have to devise lens barrels which will hold up to twenty separate elements per lens , accurately aligned and spaced , which will not be affected by the air temperature around them .
Each glass surface is coated with several thin films of transparent material to minimize internal light reflections . Without this " blooming " , reflections from the dozens of air - to- glass surfaces would give a gray , flat image , like looking through a number of windows . Look into a good quality modern lens , and you will often see the slight yellow or purple " bloom " reflected from the outer coating of its top surface . Turn the lens around and look through it , and this color disappears . Coated lenses are not only essential for modern multi - element designs , they also greatly reduce light flare when you are photographing toward a bright light source . If you buy a secondhand lens made in the 1950s before they were all coated , you will see its notably poorer performance under these conditions .
This also explains why you must take such care when cleaning the camera lens , see page 211. If you wipe it with an ordinary cloth you may scratch the coating layer or the relatively soft optical glass beneath . A lens damaged in this way may scatter light , giving you a grayer , less brilliant image . Similarly , dropping your lens may not appear to create much damage but it can misalign some of the glass components , and so seriously upset image quality .
Using lens attachments and filters
Camera lenses have to be designed for a known set of working conditions - say for subject distances ranging from infinity down to two or three feet . So each lens has a near focusing limit . Attachments such as rings or bellows enable you to focus nearer subjects , but the lens is not then performing under its intended conditions and image definition may be slightly poorer . Perhaps the corners will look less sharp than the image center . Close - up rings and bellows are difficult to use on a viewfinder camera because you cannot see what is in focus . Some solutions to these problems are discussed in the third Step , showing lens attachments . The previous Step covers color filters for black and white photography . Before working with these you should look forward to the details on complementary colors on pages 148 and 160-1 . They explain unfamiliar color names , such as magenta and cyan , and shows how primary and com- plementary ( opposite ) colors relate to each other .
Unlike lenses , filters will fit on any camera , provided they match the lens diameter . But if you work much with filters , you will find it easiest to use a single lens reflex camera with " through - the - lens " metering . A filter over the lens reduces light reaching the film as well as affecting the image . Through - the- lens meters will read the correct exposure , allowing for the filter ; while the reflex viewing will show you how the filter alters the picture tones . With viewfinder cameras you must calculate filter exposures , and judge the filtration effects , from information supplied with the filter pack - and your own experience .
Using exposure and lighting
Step four shows you how to solve particular exposure problems- with metering techniques which give greater accuracy in extreme conditions . Before reading this part , turn back and recap basic exposure metering on pages 39-43 . You are now dealing with more difficult indoor conditions , where lighting is weak and often contrasty too . Understanding the meter response can help you to judge exposure for particular effects , or aim for an ideal tone value for the most important part of your picture . Choice of exposure can be a creative decision . Later you will learn how to follow it through in the darkroom by further control at the development stage ( see pp . 126-7 ) .
The next Step , on artificial lighting , is concerned more with the appearance of the subject than the technicalities of camera and film . If you are considering buying equipment , some of the points made here are again worth noting . If you are working in color , it is essential that you have read through pages 141-7 of the Color Photography section before starting this Step , because unlike black and white materials color films respond differently to different types of lighting .
There is a very close relationship between the quality and direction of natural daylight and the type and positioning of studio lamps or flash units . Before starting on this Step it will help you to check back to the pages in the Picture Building section on lighting ( pp . 50-3 ) , and revise your knowledge and understanding of light direction and quality .
Lighting is not just a technique to give enough illumination for convenient exposures . It is also a highly creative tool and fundamental to picture making . This applies particularly to flash , which is often just mounted on top of the camera so that every picture is lit in exactly the same way .
In the early days of flash lighting , photographers poured magnesium powder into trays and lit a slow touch paper or ignited it with sparks from a flint . The whole process was very dangerous , and the photographer had to open the shutter with one hand and fire the flash with the other . Later , magnesium foil was fitted into lampsize flashbulbs and fired by electricity . Press photographers of the 1930s used large flashbulb holders clamped to the side of their cameras .
Electronic flash units appeared after World War II , at first of very low efficiency . Since then both bulb and electronic units have steadily shrunk in size . Today the small flash cube or flash bar or " flip - flash " give several flashes before having to be changed . The electronic flash unit is often very little larger and gives several hundred low cost flashes . You can use both on long extension leads , away from the camera . Bigger , more powerful ( but more expensive ) units can be used in twos and threes instead of studio lamps . You must decide which will suit your use of flash best . Remember that the principles of lighting and the need for thought and care in picking and arranging lighting conditions apply equally to daylight , tungsten lamps , and flash lighting .
Using equipment creatively
The final pages of this section are a continuation from basic picture building . ( pp . 45-64 ) . Now however you can exploit the extra equipment which has been discussed . For example , linear perspective and lens focal length are closely related . So are aerial perspective and control of exposure and lighting . Learning to use both forms of perspective enables you to increase or suppress apparent depth in your pictures .
Lighting such as flash , and techniques such as camera panning and using the shallow depth of field given by long focus lenses , allow you to give emphasis to particular elements in your picture . Try some of these effects yourself - your experiments may encourage you to buy some of the equipment seen earlier .
By the end of this section you will see how each worthwhile piece of equipment or technique widens the range of images that you can put on to your film . None of them however are substitutes for ideas and imagination . They are all tools , which different photographers will choose to use in quite diverse ways , as some of the individual styles presented at the end of this book show . One of the dangers of photography is that the tools are so ingeniously and beautifully made that you may start to collect equipment instead of producing pictures . But it is your own ideas , and your interest in a particular subject or effect , that should come first .
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