FINE CAMERAS AND HOW THEY ARE MADE

[Music] it takes three things to make a fine camera it takes a fine lens an accurate Rangefinder and a Precision shutter this prizewinning photograph is an enlargement from a tiny image on 35 mm FM a fine camera took this picture its Flawless lens produces pictures that have tone quality with no harsh highlights no blocked up Shadows 35mm cameras should fit the hand nicely be easy to focus quickly and accurately they should have Beauty should instill pride of ownership the creation of fine cameras as with all Precision Instruments depends on thorough scientific research on top quality build craftsmanship in this modern plant at an Arbor Michigan scientists designers engineers and Craftsmen all team together to produce a line of cameras that dollar for dollar are superior to any ma anywhere in the world world the three most important features of this fine camera are an exceptional lens ranking among the best that lens makers know how to produce an extremely accurate shutter and a most precise lens coupled focusing Rangefinder formula for a good camera lens requires a vast number of calculations to determ exactly the right radius of curvature for each surface and to Su active index of the glass a lens of good design is corrected for chromatic aberration so that all colors of the spectrum will focus to the same point a lens having insufficient color correction will bring each color to a different Focus fully color corrected lenses give you color slides of except definition color slides that project crisp and clear and are sharp over all of the screen a poor camera lens May produce an image sharp only in the center and out of focus in the corners and at the edges a good camera lens produces an image sharp all over and having no Distortion this is the product of a poor lens this critically sharp and fully corrected lens is one of the finest made in America the plant in which it is made has the most modern facilities for lens making to be found anywhere in the world and technicians of the highest scale lens elements start out as rough blanks of glass not ordinary glass but a special kind called Optical glass a sample is selected for testing from each batch of optical glass the test sample is ground and Polished on one side and one Edge and sent to the laboratory where it is tested for its refractive index that is whether it bends rays of light exactly L as specified if the test sample shows that the glass in the batch is up to specifications the blanks are ready for the lens making operations the first step is to spray a dark coating on one surface of each blank then the blanks are mounted in a special fixture known as a blocking tool before the blanks are mounted the blocking tool is heated in an electric induction heater this is one of the the very few lens blocking installations in the country employing the extremely modern induction heating method pitch is applied to the hot tool formerly pitch was heated in open pots and applied by hand the resulting gas and fumes and the many painful Burns to workers made the old method very inefficient production was about a third less than by the method you are watching now the blocking tool then goes to a cooling bath where the pitch hardens thus assuring that the blanks are held securely this particular type of blocking tool is suitable for grinding only one curved surface of the lens the lens elements vary in size and each has surfaces of different curvatures here are just a few of the many different sizes and shapes of blocking tools needed for grinding and finishing camera lenses the making of blocking tools such as these is only one of the many Special Operations involved in tooling up for lens and Camera manufacturer and one of the most important departments in this modern plant is where the special tools dyes and fixtures are made these blocking tools are a very special kind with recesses machined in the surfaces to receive the lens blank s now let's follow the lens blanks we saw a moment ago to the grinding room where the lenses are put in the Chuck of a Precision grinder modern methods have replaced the old slow hand operations in lens grinding this first grinding is called generating the spherical surface it is done with a hemispherical wheel containing Co Diamond grit after the removal of rough stock with the coar wheel there follows another grinding with a wheel containing fine Diamond grit this is one of the few Diamond grind installations in America in this fine grind operation the lens blanks are brought in a few seconds within tolerances which formerly required several hours of painstaking hand grinding to achieve after sell another and much finer grinding the lenses are thoroughly clean the surfaces have a smooth velvety appearance and the radius of their curvature is accurate within 100,000 part of an inch now the time consuming polishing Begins the lenses are still held on the same blocking tool and Polished on a lap of pitch a mixture of water and the rare earth serium oxide gives an extremely high polish it requires craftsmanship of the highest order to assure that polishing reaches its ultimate perfection periodically throughout the polishing operations the lenses are cleaned in preparation for testing the accuracy of the lens curve using one of the most precise testing devices known thetical test plate this master gauge made of quartz has been ground and Polished to the exact radius required when the gauge is placed in contact with the lens Newton rings are formed the contour lines on a map and enable the lens maker to know whether the lens meets rigid specification the number and width of these Newton Rings indicate the progress being made in the critical polishing process lenses that show many rings or decentered rings are not acceptable and are given additional polishing until they pass the Newton Rings test but they must also pass close inspection for scratches and pits after the lenses have pass inspection and a protective coating has been sprayed over the polished surfaces they are removed from the Block and remounted on another tool whose radius of curvature differs from the first one used because the curvature on one surface of each lens element is different from that of the other surface now a brief look at the photographic lens whose Beginnings have been taking shape in a lens system of this type there are six surfaces to be ground and Polished and all but the two outside surfaces have a different radius of curvature hence five different blocking tools are needed each having its particular radius of curvature the coarse and medium grindings require 10 different wheels two for each radius and the final grinding requires five more 15 in all then five different polishing heads are required and finally five different quartz test plates to check the accuracy of the various curves here is one of the finished lenses ground polished tested and having a radius of curvature accurate to a few million of an inch every lens must be centered so that its Optical axis passes exactly through its mechanical Center at first the small Red Cross reflected from its surface oscillates brings the the lens into Center alignment until the cross remains stationary proof that the lens is accurately centered then a squeeze of cold water from the operator's sponge sets the pitch firmly holding the lens so that the edge may be accurately ground with relation to the established optical center the edges are ground so that the m is precisely centered with the essential to the for of good images after centering the lenses are washed and carefully dried the lenses are given a beauty inspection for bubbles accidental surface scratches chipped edges and other imperfections easily spotted and marked in red to prevent its traveling fuction process coating of the lenses to assure the finest performance the lenses are placed in a large holder a charge of magnesium fluoride is placed in the lens coating machine on an electric heating unit then the lenses go in after the cover is lowered the air is pumped out to obtain the vacuum necessary for high quality coating the Magnesium fluoride is vaporized by the electric heater and deposits uniformly on the surface of the lenses what happens inside the glass Bell is depicted here by animation with the atmosphere exhausted of all foreign particles the Magnesium fluoride vaporizes in the electric Crucible and the tiny molecules travel in straight lines to the lens surfaces critical control enables The Operators to attain a thickness of coating equal to one qu of one wavelength of light or about 1 15 millionth of an inch should the coating exceed this thickness or fall short of it there is a considerable drop in lens performance hence great care is exercised in this phase of producing a fine lens after the bottom surfaces of the lenses have received their coating they are removed from the machine the lenses are then reversed for coating the other side among the qualities imparted to a lens by coating is to increase its speed by permitting more light to pass through here light is shown passing through an uncoated lens see how bright the incoming light is and how much dimmer the outgoing light with coated lenses the light that comes out has virtually the same intensity as the light that and coating a lens reduces flare lets you shoot into the light an uncoated lens produces pictur spoiling flare besides improving the quality of pictures especially color transparencies lens coating helps eliminate flare or ghost images such as you see here a coated lens gives you this lens elements no matter how fine and accurate each one is perform well only if they are mounted properly any decentering or misalignment of the elements in mounting ruin the picture making qualities of the lens so the fine photographic lens needs not only extremely skillful craftsmanship in making the individual elements but also the same high standards of craftsmanship in making the lens mount the lens elements and mounts are assembled by Nimble fingers then comes the test for sharpness and focus adjustment and to make sure that the lenses meet the established standards they are carefully checked in the laboratory here on the optical bench the lens is test stigmatism flatness of field sharpness color correction coma Distortion and a host of other things a fine lens is a jeweled embodiment of all the skill and care that has gone into its design and making just as important as a fine lens which speaks the truth and the picture it makes is a shutter which speaks only the truth when it makes the exposures camera owners like to be certain that the shutter speed is exactly what the setting indicates as you know there are three principal types of shutters the between the lens the behind the lens and the focal plane shutter this camera is typical of those equipped with a between the lens shutter these cameras have behind the lens shutters whose mechanism is contained within the camera body itself this behind the lens shutter like a fine watch typifies the highest degree of performance a and dependability the Precision which has been built into this shutter is the finest that Machining skill can produce the metal of which the parts are made must pass many tests for hardness springiness and other necessary qualities light flexible Swedish steel is stamped into shutter leaves then skilled hands begin the Assembly of the many parts of the shutter the shutter assembly goes onto the front plate then the objective lens a most important operation is setting the shutter the front plate and a frame then the lens mount Barrel is installed The Flash synchronizer is checked the camera is nearing completion as the rangefinder is installed the rangefinder is carefully adjusted and checked for activ accy then the focusing barrel and RAM rings are attached the focusing scale is very carefully adjusted and set firmly in place after the focusing scale has been set the shutter must pass a final series of tests a checking at every speed setting this electronic equipment maintains ceaseless control on shutter accuracy and synchronizer performance after assembly has been completed all cameras are carefully inspected the final step the camera receives its attractive durable covering quality control is exercised in every single manufacturing step the laboratory conducts continuing tests on shutters and lenses this oscilloscope like a miniature TV screen affords a visual picture of shutter and synchronizer performance in addition it records it photographically for study here is a black and white oscilloscopic trace the lower image composed of tiny dots each representing a predetermined fraction of a second shows exactly how long it takes the camera shutter to open how long the shutle remains open and how quickly it closes at the end of the exposure the thin line above this image shows the flash duration with relation to position good accurate synchronization produces a tracing like this showing that the flash is occurring neither too early nor too late to be fully utiliz next in importance to lens and shutter is a finder that's easy to use this camera has a brilliant reflex finder enabling you to see clearly the picture you're going to get this is a beginner's camera with fixed Focus lens makes good pictures of subjects 7 1/2 ft away and farther another type of camera with reflex finder provides for focusing from the most distant subjects to those very close up lens cupen finder focusing is the most convenient means ever devised and the most accurate before focusing the eye sees a Double Image within the circle as the focusing knob is turned one image moves until it merges with the other now the lens is in Focus the rangefinder is accurate over the entire focusing range that has been assured by painstaking tests during assembly with this combined range and viewfinder you can even wear glasses and still get a large clear image Precision in a rangefinder is essential especially when shooting wide open a camera having a built-in flash synchronizer adds to picture making pleasure particularly if it's easy to plug in and you have no dangling wires to ins to prevent here's a well-known 35mm camera with built-in flash synchronizer and a plug-in flash unit and here's America's most distinguished 35mm camera getting ready for Flash photography this fine camera has a built-in as well as built-in synchronizer to take care of all commonly used flash lamps and here is the convenient built-in delay switch set at F the fast or gas fill bulbs with their 5 millisecond delay are accurately synchronized set at M or medium the slower 20 millisecond delay bulbs function accurately the convenient Flash gun has a removable adapter so you may easily use any at any shutter speed in this camera you can use any of these lamps with a shutter speed specified for each for perfectly exposed flash pictures in black and white or color camera in addition to winding the film for the next exposure also winds the shutter and sets the EXP exposure counter the real pleasure of owning and using a fine camera depends on the lens the shutter and the focusing mechanism a lens accurately ground and Polished coated color corrected and in a precise mounting a finder that gives large clear images combined with precise coupled Rangefinder focusing and a sturdy rugged shutter built to the highest standards of accuracy and precision and the reward for using a fine camera is the real pleasure and enjoyment its pictures [Music] provide [Music] l