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SPECIAL PURPOSE CAMERAS
We come now to cameras of an entirely different class - the special - purpose cameras which have been designed to do one job and do it well . They are , therefore , more limited in their general use .
POLAROID CAMERA . The Polaroid Land camera ( Figure 27 ) is radically different from all other cameras . It has a number of extremely interesting features which place it in a class by itself . It was perfected by Dr. Edwin H. Land , who is also well known for his studies in polarized light and his development of polarizing filters .
Figure 27 Polaroid Sonar self - focusing camera .
The Polaroid camera is loaded with a double - layer roll of film . One layer is the negative . The other layer is the paper on which the final print is made . This is called positive paper . The exposure is made on the negative emulsion in the usual way , but when the film is advanced for the next exposure , an interesting sequence . of events takes place . Attached to the sensitive film at suitable intervals are pods of jellied chemicals . As the next section of film is being wound into place , the exposed film and its matching paper positive pass through a set of stainless steel rollers . These rollers crush the pods of processing chemicals and spread them uniformly over the sensitive surfaces . The result is a kind of sandwich of film ( negative ) , chemicals , and positive paper .
The processing chemicals in a pod consist primarily of a rapid developer , fixer , and stabilizer . The entire processing operation is completed in approximately ten seconds for black - and - white film and 50 seconds for color film . At the end of that time the two sheets are pulled out of the camera , separated , and the negative is thrown away . The print is barely moist from the jellied chemicals and dries in a few minutes .
There are quite a number of different models of Polaroid cameras , as well as Polaroid backs which may be fitted to other cameras such as view cameras and Speed Graphics . Some of these provide the usual positive prints , while others produce negatives or transparencies ( slides ) for projection .
THE FINGER - PRINT CAMERA . ( Figure 28 ) This camera which is used for photographing fingerprints , textiles , signatures , stamps , or other flat objects , is a complete self - contained unit with lamps inside to illuminate the object . It is , of course , primarily designed for police work .
Figure 28 A camera built for at single purpose taking pictures of fingerprints .
THE CLINICAL CAMERA . ( Figure 29 ) This camera is specially designed for the physician , surgeon , or pathologist to use when making case records . In some cameras , provision is made for taking a series of pictures to a definite scale . Others have built - in electronic flash and take close - up clinical pictures of such objects as the eye , or the inside of the mouth .
THE STEREOSCOPIC CAMERA . The area of stereophotography is taken up later in this course of study so we will not discuss this subject here except to show a typical stereo camera in Figure 30 .
THE COPY CAMERA . ( Figure 31 ) Any good view camera can be used for copy work , but a specially designed copy camera is more convenient . It is generally built more solidly and has a longer bellows extension than a view camera , but it does not have a wide range of movements for the lens board and the focusing back .
Figure 29 This clinical camera can easily be adapted to take pictures through a microscope .
Figure 30 This is a classic 3 - D camera , which is now a collector's item .
Figure 31 A large commercial copy camera which can be used either horizontally , as shown , or vertically .
THE AERIAL CAMERA . As its name implies , this camera is intended for use in an airplane . The simpler aerial cameras are merely heavy duty cameras with special lens mounts and heavy handles so they can be held more rigidly . The more elaborate cameras are equipped with a battery of as many as nine lenses and mirrors to take , simultaneously , a number of pictures for aerial mapping .
THE BANQUET CAMERA . This is really nothing more than a very large box camera built something like a pyramid with the lens at the small end . It is used to photograph large indoor groups such as guests at a banquet . These cameras use extremely wide - angle lenses which are stopped down to very small openings and tilted forward slightly . Because of the relatively short focal length , the tilt of the lens and the small aperture , no focusing is necessary so that the box construction can be used .
THE HALF - FRAME CAMERA . The standard 35mm camera makes a picture a shade under 1 x 1½ in . in size . This is the picture size of the original high quality . 35mm camera , the Leica . All other 35mm still cameras adopted this size so consequently it quickly became the standard . Actually , the film used was standard 35mm motion picture film , and the standard movie frame , or picture , was 3/4 x 1 in . at that time . The 35mm still cameras were thus often referred to at first as double frame cameras , particularly since there were a few early still cameras using motion picture film which took the standard movie 35mm frame of 3/4 x 1 in . However , none of these early cameras were used for serious photography and they were all discontinued eventually . The still photographer , as distinct from the movie photographer , thus considered the 1 x 1½ size picture made by his camera as a standard for 35mm cameras . As 35mm cameras , lenses and film emulsions were improved over the years , it became possible to get pictures of quite satisfactory quality with 35mm equipment , and now a 35mm camera is used by a good many commercial photographers either by choice or where a larger camera is not practical . When this stage in the development of 35mm photography was reached , it occurred to camera manufacturers that satisfactory results for amateur or non - critical use could be obtained with a picture size half that of the regular 35mm . They , therefore , introduced what is now known as the half frame camera , which takes a picture only 3/4 x 1 in . , half the standard 35mm size , but still using the standard 35mm film .
The half frame camera can actually produce as good , or better , results than the full frame cameras did in the 30's and 40's . There are a number of half frame cameras on the market with very good optics and these can hardly be considered toy cameras . However , the majority of half frame cameras are intended primarily for the amateur and are built down to a price . In Figure 32 , we show one of the better cameras in this field .
THE SUB - MINIATURE CAMERA . The sub - miniature camera is admittedly a special - purpose camera . It's primary use is for the amateur who wants a small snapshot , and as light and inconspicuous a camera as he can possibly get . However , there are times when a press photographer must take a picture without his being caught at it , and in those circumstances , he may resort to the use of a sub - miniature and accept the admittedly inferior quality on the basis that a poor picture is better than nothing at all .
Figure 32 This 5 ounce camera ( shown actual size ) uses standard 35 mm film which can be enlarged to 16 " by 20 " and larger .
Figure 33 A popular 35 mm subminature camera .
This is not to say that sub - miniature cameras are of inferior quality as such . Quite the contrary . Some of them are amazingly precise instruments and have all the features of their bigger brothers . It is simply that there is inevitably a considerable loss in sharpness and general picture quality when these exceedingly tiny pictures are greatly enlarged .
There are quite a number of sub - miniature cameras and they vary widely in size , shape and type . A typical sub - miniature camera is shown in Figure 33 .
The original high quality sub - miniature , the Minox , takes an 8 x 11mm picture on special 9.5mm film . Most sub - miniature cameras , however , use 16mm motion picture film and make a picture 10 x 14mm in size . Some sub - miniatures use unperforated 16mm film , which gives them the larger picture size of 12 x 17mm .
تعرف على كاميرات ذات أغراض خاصة ..
SPECIAL PURPOSE CAMERAS
We come now to cameras of an entirely different class - the special - purpose cameras which have been designed to do one job and do it well . They are , therefore , more limited in their general use .
POLAROID CAMERA . The Polaroid Land camera ( Figure 27 ) is radically different from all other cameras . It has a number of extremely interesting features which place it in a class by itself . It was perfected by Dr. Edwin H. Land , who is also well known for his studies in polarized light and his development of polarizing filters .
Figure 27 Polaroid Sonar self - focusing camera .
The Polaroid camera is loaded with a double - layer roll of film . One layer is the negative . The other layer is the paper on which the final print is made . This is called positive paper . The exposure is made on the negative emulsion in the usual way , but when the film is advanced for the next exposure , an interesting sequence . of events takes place . Attached to the sensitive film at suitable intervals are pods of jellied chemicals . As the next section of film is being wound into place , the exposed film and its matching paper positive pass through a set of stainless steel rollers . These rollers crush the pods of processing chemicals and spread them uniformly over the sensitive surfaces . The result is a kind of sandwich of film ( negative ) , chemicals , and positive paper .
The processing chemicals in a pod consist primarily of a rapid developer , fixer , and stabilizer . The entire processing operation is completed in approximately ten seconds for black - and - white film and 50 seconds for color film . At the end of that time the two sheets are pulled out of the camera , separated , and the negative is thrown away . The print is barely moist from the jellied chemicals and dries in a few minutes .
There are quite a number of different models of Polaroid cameras , as well as Polaroid backs which may be fitted to other cameras such as view cameras and Speed Graphics . Some of these provide the usual positive prints , while others produce negatives or transparencies ( slides ) for projection .
THE FINGER - PRINT CAMERA . ( Figure 28 ) This camera which is used for photographing fingerprints , textiles , signatures , stamps , or other flat objects , is a complete self - contained unit with lamps inside to illuminate the object . It is , of course , primarily designed for police work .
Figure 28 A camera built for at single purpose taking pictures of fingerprints .
THE CLINICAL CAMERA . ( Figure 29 ) This camera is specially designed for the physician , surgeon , or pathologist to use when making case records . In some cameras , provision is made for taking a series of pictures to a definite scale . Others have built - in electronic flash and take close - up clinical pictures of such objects as the eye , or the inside of the mouth .
THE STEREOSCOPIC CAMERA . The area of stereophotography is taken up later in this course of study so we will not discuss this subject here except to show a typical stereo camera in Figure 30 .
THE COPY CAMERA . ( Figure 31 ) Any good view camera can be used for copy work , but a specially designed copy camera is more convenient . It is generally built more solidly and has a longer bellows extension than a view camera , but it does not have a wide range of movements for the lens board and the focusing back .
Figure 29 This clinical camera can easily be adapted to take pictures through a microscope .
Figure 30 This is a classic 3 - D camera , which is now a collector's item .
Figure 31 A large commercial copy camera which can be used either horizontally , as shown , or vertically .
THE AERIAL CAMERA . As its name implies , this camera is intended for use in an airplane . The simpler aerial cameras are merely heavy duty cameras with special lens mounts and heavy handles so they can be held more rigidly . The more elaborate cameras are equipped with a battery of as many as nine lenses and mirrors to take , simultaneously , a number of pictures for aerial mapping .
THE BANQUET CAMERA . This is really nothing more than a very large box camera built something like a pyramid with the lens at the small end . It is used to photograph large indoor groups such as guests at a banquet . These cameras use extremely wide - angle lenses which are stopped down to very small openings and tilted forward slightly . Because of the relatively short focal length , the tilt of the lens and the small aperture , no focusing is necessary so that the box construction can be used .
THE HALF - FRAME CAMERA . The standard 35mm camera makes a picture a shade under 1 x 1½ in . in size . This is the picture size of the original high quality . 35mm camera , the Leica . All other 35mm still cameras adopted this size so consequently it quickly became the standard . Actually , the film used was standard 35mm motion picture film , and the standard movie frame , or picture , was 3/4 x 1 in . at that time . The 35mm still cameras were thus often referred to at first as double frame cameras , particularly since there were a few early still cameras using motion picture film which took the standard movie 35mm frame of 3/4 x 1 in . However , none of these early cameras were used for serious photography and they were all discontinued eventually . The still photographer , as distinct from the movie photographer , thus considered the 1 x 1½ size picture made by his camera as a standard for 35mm cameras . As 35mm cameras , lenses and film emulsions were improved over the years , it became possible to get pictures of quite satisfactory quality with 35mm equipment , and now a 35mm camera is used by a good many commercial photographers either by choice or where a larger camera is not practical . When this stage in the development of 35mm photography was reached , it occurred to camera manufacturers that satisfactory results for amateur or non - critical use could be obtained with a picture size half that of the regular 35mm . They , therefore , introduced what is now known as the half frame camera , which takes a picture only 3/4 x 1 in . , half the standard 35mm size , but still using the standard 35mm film .
The half frame camera can actually produce as good , or better , results than the full frame cameras did in the 30's and 40's . There are a number of half frame cameras on the market with very good optics and these can hardly be considered toy cameras . However , the majority of half frame cameras are intended primarily for the amateur and are built down to a price . In Figure 32 , we show one of the better cameras in this field .
THE SUB - MINIATURE CAMERA . The sub - miniature camera is admittedly a special - purpose camera . It's primary use is for the amateur who wants a small snapshot , and as light and inconspicuous a camera as he can possibly get . However , there are times when a press photographer must take a picture without his being caught at it , and in those circumstances , he may resort to the use of a sub - miniature and accept the admittedly inferior quality on the basis that a poor picture is better than nothing at all .
Figure 32 This 5 ounce camera ( shown actual size ) uses standard 35 mm film which can be enlarged to 16 " by 20 " and larger .
Figure 33 A popular 35 mm subminature camera .
This is not to say that sub - miniature cameras are of inferior quality as such . Quite the contrary . Some of them are amazingly precise instruments and have all the features of their bigger brothers . It is simply that there is inevitably a considerable loss in sharpness and general picture quality when these exceedingly tiny pictures are greatly enlarged .
There are quite a number of sub - miniature cameras and they vary widely in size , shape and type . A typical sub - miniature camera is shown in Figure 33 .
The original high quality sub - miniature , the Minox , takes an 8 x 11mm picture on special 9.5mm film . Most sub - miniature cameras , however , use 16mm motion picture film and make a picture 10 x 14mm in size . Some sub - miniatures use unperforated 16mm film , which gives them the larger picture size of 12 x 17mm .
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