تويت
التصوير الفوتوغرافي الحديث
التصوير الفوتوغرافي الأساسي للصور المتحركة
استخدام الكاميرا الخاصة بك
USING YOUR CAMERA
From a purely photographic point of view , considering such matters as lighting , exposure , and general photographic quality , the taking of movies is essentially the same as the taking of still pictures . Differences that exist are mainly of a technical nature . Only these will be discussed in this Assignment .
SELECTING THE PROPER LENS . The lenses used in movie cameras have extremely short focal lengths . As a result they have great depth of field , which makes focusing a relatively simple matter even with very fast lenses . Some of the lower priced 8mm cameras have no provision for focusing ; the lenses are simply pre - focused for maximum depth of field at the factory . With the 10 to 12mm lenses used in 8mm cameras , this permits the taking of sharp pictures down to 10 feet or less with an aperture of f / 1.9 , and less than 6 feet at f / 4 . However , focusing is necessary for shorter distances and for telephoto work .
Another advantage of the short focal length of a movie lens is that it can have good correction at exceedingly large apertures . An f / 1.9 lens , for example , is quite a fast lens for even a 35mm still camera ; it is about the slowest lens you will find in anything but the lowest priced 8mm movie camera . Finely corrected movie lenses can have speeds in the neighborhood of f / 1.4 or even faster . Telephoto lenses and zoom lenses , however , will run a stop or two slower . The question of how fast a lens to buy is , therefore , a simple one to answer the fastest you can afford up to about f / 1.4 for the standard lenses , about f / 1.6 in zoom lenses , and f / 2 in telephotos . Beyond that point , picture sharpness and brilliance are likely to suffer .
For anything but the most casual use , it is advisable to have an assortment of lenses of different focal lengths . It is often impossible to change the camera position to take in a wider or narrower angle of view . In such cases , an assortment of lenses is necessary . A good assortment will consist of a wide - angle lens , a standard lens and one or two telephotos .
Taking the 8mm camera as an example , the standard lens has a focal length of 12mm . This is actually a fairly long focal length for this picture size , taking in only 21.5 ° on the long side of the film . This is less than half the angle considered normal for still photography . To permit working in fairly tight quarters , a wide - angle lens is essential . The widest angle lens generally available for 8mm movie use is 6.5mm . Actually its angle is slightly less than the standard lenses supplied with still cameras . So you see , there is really no such thing as a true wide - angle lens for movie cameras .
Any lens longer than 12.5mm on an 8mm camera , or 25mm on a 16mm camera is considered a telephoto lens . The magnification provided by a telephoto lens can be determined very simply by dividing its focal length by the focal length of the standard lens . A 25mm lens on an 8mm movie camera , for which 12 / 2mm is standard , will give a 2 ( two ) times magnification . A comparison of the pictures taken with lenses of different focal length are shown in Figures 6 through 9 .
A good collection of lenses for a 16mm camera listed in the order of relative usefulness is given in Table II .
TABLE II
1. 25mm - Standard angle
2. 13mm Wide angle
3. 50mm - Telephoto
4. 75mm - Telephoto
Figure 6 Beach scene as taken with an 8mm camera equipped with a 9mm wide - angle lens .
Figure 7 Same scene as Figure 6 but taken with a 12.5mm ) normal - focus lens .
Figure 8 Same scene as Figure 6 but taken with an 18mm ) telephoto lens .
Figure 9 Same scene as Figure 6 but taken with 28mm telephoto lens .
The telephoto lens has two purposes . The first , of course , is to provide a larger image size from the same viewpoint . This is very useful in many ways . Quite often it is impossible to get close enough to the subject to fill the screen properly . In such a situation , the telephoto lens is the answer . There are also times when the photographer wishes to keep his distance so as not to disturb his subject . Taking pictures of insects or animals is usually best done at a distance ; travel pictures of street scenes are frequently better when taken with a telephoto lens because the people are much less likely to be aware of the fact that they are being photographed .
The second important use of the telephoto lens is to change the relative size of the foreground subject to its background . For example , let us say you wish to take a picture of a subject posed in front of distant mountains . With a normal . lens , if you move up close enough to the subject so it fills the screen comfortably , the background mountains appear small and unimpressive . ( See Figure 10. ) Now , instead of the standard lens , suppose you use a 2X telephoto lens . You now must move back to twice the distance from the people so they still fill the screen comfortably . However , the distance between you and the mountains will not have changed appreciably by the few feet you have moved back , so they will appear twice the height with this telephoto lens . Note how much more impressive the mountains appear in Figure 11 than they do in Figure 10 .
Figure 10 Scene taken with an 8mm camera and a standard 12.5 normal - focus lens .
Figure 11 Same scene as Figure 10 but taken with a 25mm telephoto lensi and with the camera moved back until the couple in the foreground were the same image size . Note the increased image size and the dramatic appearance of the mountains the background ..
Figure 12 A steep city street taken with a lens of normal focal length . The steepness of the street is not really apparent .
Figure 13 The same street as in Figure 12 but taken with a telephoto lens . Now the steepness of the street is quite apparent .
The telephoto lens has another important use which is seldom taken advantage of by the photographer . It is usually quite difficult to capture the feeling of height in a very steep city street or a tall mountain with an ordinary lens . The telephoto , because it permits the photographer to get back quite a distance from the subject , produces a much stronger effect of height . For example , Figure 12 pictures one of the San Francisco streets , but its steepness is not at all evident in this view , which was taken with a standard lens . Figure 13 was taken from the same spot , but with a telephoto lens . See how the telephoto shot has captured the steepness of the street .
In using a telephoto lens , it is always best to use a tripod . Just as a telephoto lens magnifies the image , so does it magnify camera movement . The slight camera shake , unavoidable when the camera is held in the hand , is not too noticeable with the standard lens if the camera is held steady . Even a 2X telephoto lens , however , will increase wobble to an annoying degree .
THE ZOOM LENS . Undoubtedly the most interesting and certainly the most universal of all movie camera lenses is a zoom lens . This lens is one whose focal length can be varied through a very wide range , so one lens serves as a wide - angle , normal , or telephoto lens simply by pulling a lever or rotating the lens barrel . It is extremely effective when it is necessary to zoom down to a close - up , or back away to broaden the field of view .
The zoom lens is called upon to do an extremely complicated and difficult job . While its focal length is being varied by as much as 3 or 4 to 1 , its overall length must change only to a limited extent , and the plane on which it is focused must remain constant while it is zooming or the picture will go out of focus .
Before filming a scene which includes zooming in on a subject , practice the zoom action a time or two . In order to keep your subject properly positioned in the frame , you may have to pan the camera right or left and perhaps up or down simultaneously as you zoom in . In the scene shown here , to end your zoom on the boy , your camera must be panned right and down slightly while zooming .
All these complications impose several limitations on the lens design . As a result , the zoom lens is not quite as sharp as a conventional lens . While it is adequate in this respect for home movies and many TV applications , the serious worker or the commercial photographer who demands razor sharpness in his films may prefer a good selection of individual lenses . The zoom lens generally has a focal length range of about 9 to 38mm for 8mm cameras , and 18 to 75mm for 16mm cameras . Unfortunately , the zoom lens and its viewfinder are so specialized that they are usually built into the camera . This makes it impossible to use other lenses with a zoom camera .
In general , you might follow these guidelines if you are considering buying movie equipment . If you want a simple camera for ordinary home movie use , get one with a zoom lens . If you want to make serious movies and require the greatest versatility and the sharpest pictures , get one of the better turret models with a good assortment of lenses . Some photographers have both a zoom and a turret camera , since the zoom effect itself when properly used can introduce a great deal of force and movement into a movie sequence .
التصوير الفوتوغرافي الأساسي للصور المتحركة
استخدام الكاميرا الخاصة بك
USING YOUR CAMERA
From a purely photographic point of view , considering such matters as lighting , exposure , and general photographic quality , the taking of movies is essentially the same as the taking of still pictures . Differences that exist are mainly of a technical nature . Only these will be discussed in this Assignment .
SELECTING THE PROPER LENS . The lenses used in movie cameras have extremely short focal lengths . As a result they have great depth of field , which makes focusing a relatively simple matter even with very fast lenses . Some of the lower priced 8mm cameras have no provision for focusing ; the lenses are simply pre - focused for maximum depth of field at the factory . With the 10 to 12mm lenses used in 8mm cameras , this permits the taking of sharp pictures down to 10 feet or less with an aperture of f / 1.9 , and less than 6 feet at f / 4 . However , focusing is necessary for shorter distances and for telephoto work .
Another advantage of the short focal length of a movie lens is that it can have good correction at exceedingly large apertures . An f / 1.9 lens , for example , is quite a fast lens for even a 35mm still camera ; it is about the slowest lens you will find in anything but the lowest priced 8mm movie camera . Finely corrected movie lenses can have speeds in the neighborhood of f / 1.4 or even faster . Telephoto lenses and zoom lenses , however , will run a stop or two slower . The question of how fast a lens to buy is , therefore , a simple one to answer the fastest you can afford up to about f / 1.4 for the standard lenses , about f / 1.6 in zoom lenses , and f / 2 in telephotos . Beyond that point , picture sharpness and brilliance are likely to suffer .
For anything but the most casual use , it is advisable to have an assortment of lenses of different focal lengths . It is often impossible to change the camera position to take in a wider or narrower angle of view . In such cases , an assortment of lenses is necessary . A good assortment will consist of a wide - angle lens , a standard lens and one or two telephotos .
Taking the 8mm camera as an example , the standard lens has a focal length of 12mm . This is actually a fairly long focal length for this picture size , taking in only 21.5 ° on the long side of the film . This is less than half the angle considered normal for still photography . To permit working in fairly tight quarters , a wide - angle lens is essential . The widest angle lens generally available for 8mm movie use is 6.5mm . Actually its angle is slightly less than the standard lenses supplied with still cameras . So you see , there is really no such thing as a true wide - angle lens for movie cameras .
Any lens longer than 12.5mm on an 8mm camera , or 25mm on a 16mm camera is considered a telephoto lens . The magnification provided by a telephoto lens can be determined very simply by dividing its focal length by the focal length of the standard lens . A 25mm lens on an 8mm movie camera , for which 12 / 2mm is standard , will give a 2 ( two ) times magnification . A comparison of the pictures taken with lenses of different focal length are shown in Figures 6 through 9 .
A good collection of lenses for a 16mm camera listed in the order of relative usefulness is given in Table II .
TABLE II
1. 25mm - Standard angle
2. 13mm Wide angle
3. 50mm - Telephoto
4. 75mm - Telephoto
Figure 6 Beach scene as taken with an 8mm camera equipped with a 9mm wide - angle lens .
Figure 7 Same scene as Figure 6 but taken with a 12.5mm ) normal - focus lens .
Figure 8 Same scene as Figure 6 but taken with an 18mm ) telephoto lens .
Figure 9 Same scene as Figure 6 but taken with 28mm telephoto lens .
The telephoto lens has two purposes . The first , of course , is to provide a larger image size from the same viewpoint . This is very useful in many ways . Quite often it is impossible to get close enough to the subject to fill the screen properly . In such a situation , the telephoto lens is the answer . There are also times when the photographer wishes to keep his distance so as not to disturb his subject . Taking pictures of insects or animals is usually best done at a distance ; travel pictures of street scenes are frequently better when taken with a telephoto lens because the people are much less likely to be aware of the fact that they are being photographed .
The second important use of the telephoto lens is to change the relative size of the foreground subject to its background . For example , let us say you wish to take a picture of a subject posed in front of distant mountains . With a normal . lens , if you move up close enough to the subject so it fills the screen comfortably , the background mountains appear small and unimpressive . ( See Figure 10. ) Now , instead of the standard lens , suppose you use a 2X telephoto lens . You now must move back to twice the distance from the people so they still fill the screen comfortably . However , the distance between you and the mountains will not have changed appreciably by the few feet you have moved back , so they will appear twice the height with this telephoto lens . Note how much more impressive the mountains appear in Figure 11 than they do in Figure 10 .
Figure 10 Scene taken with an 8mm camera and a standard 12.5 normal - focus lens .
Figure 11 Same scene as Figure 10 but taken with a 25mm telephoto lensi and with the camera moved back until the couple in the foreground were the same image size . Note the increased image size and the dramatic appearance of the mountains the background ..
Figure 12 A steep city street taken with a lens of normal focal length . The steepness of the street is not really apparent .
Figure 13 The same street as in Figure 12 but taken with a telephoto lens . Now the steepness of the street is quite apparent .
The telephoto lens has another important use which is seldom taken advantage of by the photographer . It is usually quite difficult to capture the feeling of height in a very steep city street or a tall mountain with an ordinary lens . The telephoto , because it permits the photographer to get back quite a distance from the subject , produces a much stronger effect of height . For example , Figure 12 pictures one of the San Francisco streets , but its steepness is not at all evident in this view , which was taken with a standard lens . Figure 13 was taken from the same spot , but with a telephoto lens . See how the telephoto shot has captured the steepness of the street .
In using a telephoto lens , it is always best to use a tripod . Just as a telephoto lens magnifies the image , so does it magnify camera movement . The slight camera shake , unavoidable when the camera is held in the hand , is not too noticeable with the standard lens if the camera is held steady . Even a 2X telephoto lens , however , will increase wobble to an annoying degree .
THE ZOOM LENS . Undoubtedly the most interesting and certainly the most universal of all movie camera lenses is a zoom lens . This lens is one whose focal length can be varied through a very wide range , so one lens serves as a wide - angle , normal , or telephoto lens simply by pulling a lever or rotating the lens barrel . It is extremely effective when it is necessary to zoom down to a close - up , or back away to broaden the field of view .
The zoom lens is called upon to do an extremely complicated and difficult job . While its focal length is being varied by as much as 3 or 4 to 1 , its overall length must change only to a limited extent , and the plane on which it is focused must remain constant while it is zooming or the picture will go out of focus .
Before filming a scene which includes zooming in on a subject , practice the zoom action a time or two . In order to keep your subject properly positioned in the frame , you may have to pan the camera right or left and perhaps up or down simultaneously as you zoom in . In the scene shown here , to end your zoom on the boy , your camera must be panned right and down slightly while zooming .
All these complications impose several limitations on the lens design . As a result , the zoom lens is not quite as sharp as a conventional lens . While it is adequate in this respect for home movies and many TV applications , the serious worker or the commercial photographer who demands razor sharpness in his films may prefer a good selection of individual lenses . The zoom lens generally has a focal length range of about 9 to 38mm for 8mm cameras , and 18 to 75mm for 16mm cameras . Unfortunately , the zoom lens and its viewfinder are so specialized that they are usually built into the camera . This makes it impossible to use other lenses with a zoom camera .
In general , you might follow these guidelines if you are considering buying movie equipment . If you want a simple camera for ordinary home movie use , get one with a zoom lens . If you want to make serious movies and require the greatest versatility and the sharpest pictures , get one of the better turret models with a good assortment of lenses . Some photographers have both a zoom and a turret camera , since the zoom effect itself when properly used can introduce a great deal of force and movement into a movie sequence .
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