CLINICAL PHOTOGRAPHY www.indiandentalacademy.com
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
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CONTENTS o o o o o o o o o o o o
INTRODUCTION CAMERAS AND PARTS LENSES SHUTTER APERTURE EXPOSURE FILM LIGHTING FOCUSING CLINICAL TECHNIQUES DIGITAL PHOTOGRAPHY CONCLUSION www.indiandentalacademy.com
INTRODUCTION
1st camera – Italy ‘CAMERA OBSCURE’ (dark chamber) Huge box with a tiny opening on one side. On the opposite side light formed an inverted image.
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CAMERA
BODY LENS SHUTTER VIEW-FINDER
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PRINCIPLE EMPLOYED IN CAMERA
The camera works in much the same way as our eye. Shutter – eye lid Aperture –iris Lens-lens Film-retina
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TYPES OF CAMERAS # Sheet Film Cameras
# Non-Reflex Cameras - Snap Shot Cameras - Range Finder Cameras www.indiandentalacademy.com
TYPES OF CAMERAS # Disc Cameras
# Cartridge Load Cameras
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TYPES OF CAMERAS # Instant Picture Cameras
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TYPES OF CAMERAS # Twin Lens Reflex Cameras
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TYPES OF CAMERAS # Single Lens Reflex Cameras
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TYPES OF CAMERAS # Panoramic Cameras # Underwater Cameras # Stereographic Cameras # Aerial Cameras # Electronic Cameras.
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LENSES
Heart of the camera.
Complex works of engineering
PRINCIPLE – same as that of a magnifying lens which gathers light of the sun to burn paper.
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PHYSICS IN LENSES
REFRACTION- The bending of light on entering a different transparent medium.
REFRACTIVE INDEX- The bending power of the medium. www.indiandentalacademy.com
LENSES ď Ź
Series of prisms stacked up.
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ABERRATIONS IN LENSES
Spherical Aberrations
Chromatic Aberrations
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FEATURES OF LENSES ďƒ˜
Covering Power of a LensThe point at which the image falls below an acceptable standard, marks the circle of good definition. For a 35mm camera one frame is 24x36mm and frame diagonal is 43mm.
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FEATURES OF LENSES ďƒ˜ FOCAL
LENGTH AND MAGNIFICATIONFocal Length is the distance from the lens to the film to get a sharp image of an object.
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• •
Lenses with higher focal length form magnified images, but show a restricted field of view and vice-versa . Shorter F.L -> WIDE ANGLE LENSES. Longer F.L -> TELEPHOTO LENSES www.indiandentalacademy.com
DEPTH OF FIELD ď Ź
Zone of in focus elements from front to back.
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TYPES OF LENSES STANDARD
LENSES WIDE ANGLE LENSES TELEPHOTO LENSES
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DRONACHARYA’S TEST
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TYPES OF LENSES ď Ź
STANDARD LENSES- These lenses show the world as it is. - Gives you the joy of having far away and near to objects , clearly captured and sharp enough. www.indiandentalacademy.com
TYPES OF LENSES ď Ź
WIDE ANGLE LENSES- Provide maximum amount of depth of field. - Background seems farther away. Foreground is in focus. www.indiandentalacademy.com
TYPES OF LENSES ď ś
TELEPHOTO LENSES- Magnified images ,fill the frame with the subject. - Focal length more than that of the lens. www.indiandentalacademy.com
TYPES OF LENSES
FISH EYE LENSES
ZOOM LENSES
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TYPES OF LENSES SPECIAL • • • •
LENSES Night lenses Shift lenses Macro lenses Medical lenses
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SHUTTER Earlier- no shutters were used. Because people used very slow light sensitive materials, which required exposure of several minutes. PURPOSETo protect the film from light until the chosen moment.
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TYPES OF SHUTTERS ď Ź
Leaf Shutterbuilt into lens. no.of thin metal plates.
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TYPES OF SHUTTERS ď Ź
Focal Plane Shutters- Essential in S.L.R cameras.
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SHUTTER SPEED Shutter speed refers to the length of the exposure time. Shutter speed shown as ‘2000’ means 1/2000 th of a sec. Slow shutter speed- 1/30, 1/2. Fast shutter speed- 1/2000,1/4000.
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APERTURE It is a hole through which the light passes from the subject to the film. Various sizes of apertures are called ‘f’ STOPS or ‘f’ NUMBERS. Size rages from 1.4-32
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APERTURE These
no.s are a measure of the size of the lens aperture NOT the diameter of the aperture. It is the number by which the focal length of the lens must be divided to yield the aperture diameter. For Eg. 50mm lens is set to f/2 aperture, diameter of the aperture is 50/2 = 25mm. ‘f’ stands for focal length. www.indiandentalacademy.com
APERTURE ď Ź
Lower the number greater the aperture size and vice-versa.
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ď Ź
Aperture and Area of sharpness. SMALL aperture- little light- render subject sharply. LARGE aperturemore light- captures shallow plane clearly.
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EXPOSURE It is the total amount of light that reaches the film in the camera. i.e. intensity of light x time.
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EXPOSURE ď Ź
Proper exposure depends upon:- Lighting - Subject - Desired depth of field.
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Each of these require an adjustment in :-shutter speed or -aperture size
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FILM 3 main types: Black and white Color Color reversal films (color slides).
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LAYERS OF A BLACK AND WHITE FILM 1. 2.
3. 4.
Scratch resistant coating Emulsion layer containing silver halide crystals in gelatin. Plastic film base. Anti-halation coating. www.indiandentalacademy.com
LAYERS OF A COLOR FILM 1. 2.
3. 4.
Scratch resistant coating 3 Emulsion layers containing dyes sensitive to blue, green and red colors in gelatin. Plastic film base. Anti-halation coating.
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COLOR REVERSAL FILMS ď Ź ď Ź
Couplers in the slide films are colorless. Processing is more complex because of the extra stages needed to turn the negative back to the positive.
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CHARECTERISTICS OF A FILM 1. 2. 3. 4.
SPEED GRAININESS COLOR SENSITIVITY COLOR BALANCE
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LIGHTING 3 sources of man made light: Incandescent Vapour Flash Electronic Flash
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FLASH TECHNIQUES
Bounce the Flash – Indirect lighting Fill in flash or Synchro sunlight – Direct lighting
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DIRECTION OF SOURCE OF LIGHT 1. 2. 3. 4. 5. 6. 7. 8. 9.
FRONT LIGHTING BACK LIGHTING SIDE LIGHTING TOP LIGHTING BOTTOM LIGHTING MULTIPLE LIGHTING MIRRORS ULTRAVIOLET LAMPS LASERS www.indiandentalacademy.com
HOW TO MAKE A PHOTOGRAPH?
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BALANCE OF THREE ELEMENTS
1. 2. 3.
SHUTTER SPEED APERTURE VALUE FILM SENSITIVITY
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SHUTTER SPEED ď Ź
Fast shutter speeds keep both fore ground and background in sharp focus.
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APERTURE VALUE
Wide aperture Minimum DOF Stopped down aperture – Max DOF
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CLINICAL ASPECT www.indiandentalacademy.com
PHOTOGRAPHIC ITEMS NEEDED
35mm SLR camera body with removable lens
Automatic bellows for Minolta or for other make of cameras
100mm automatic bellows lens (short mount style); 105mm automatic bellows lens to fit most other camera bodies.
Washington 1800 rotating light bracket.
Show and nut for bracket to hold flash unit.
Series 7 lens adapter ring or rings, depending on lens (need to attach bracket to lens; state lens make and size).
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Series 7 color correction glass filter, depending on flash used (color filters must match flash and film to be used, and also are a protection over the lens).
Vertical flash unit – guide number 45-55 for K64 film. It is not practical at this time to list the names of flash units as by the time this information is in print, a different flash may be used.
Pistol grip and 200 single cable release. A pistol grip should be used on all clinical units for single handed operation plus good balance of the unit. Large pistol grips are not practical.
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EXTRA ORAL PHOTOGRAPHY www.indiandentalacademy.com
PROCEDURE IN TAKING EXTRA ORAL VIEWS:
Acc. to Proffit (extra oral views) Frontal view with lips relaxed Frontal view with lips together Profile view with lips relaxed Profile view with lips together Smile (Angular or frontal)
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IDEAL HEAD POSITIONS ď Ź
Frontal view:- outer canthus to superior attachment of the ear (C-SA line); - Interpupillary line; - Encompassing area (crown to collarbone). www.indiandentalacademy.com
IDEAL HEAD POSITIONS ď Ź
Profile view: - canthus to superior attachment of ear - encompassing area of crown to collarbone - Chin and neck should show, preferably up to the clavicles. - Frankfort horizontal line to be sure that head is level. www.indiandentalacademy.com
ABO Requirements 1. 2. 3. 4. 5.
Quality prints either in black and white or color. Head oriented accurately in all 3 planes of space and in F-H plane. 1Lateral view- facing to the right , serious expression ,lips closed lightly. 1Anterior view- serious expression Background free of distractions. www.indiandentalacademy.com
ABO Requirements 6. 1lat view ,1ant view- (optional) with lips apart. 7. 1 ant view- (optional) smiling. 8. Quality lighting with no shadows. 9. Ears exposed for purpose of orientation. 10.Eyes opened, looking straight ; glasses removed. www.indiandentalacademy.com
Camera position for lateral view
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Hairstyle: ď Ź
Hairstyle can distract from facial analysis. Hair should be pulled back, in a ponytail, if necessary.
ď Ź
This allows for auricular analysis and for relationship between tragus and infraorbital rim to be evaluated.
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IDEAL HEAD POSITIONS
Oblique view: - Make sure that about half of opposite upper lid eyelashes show. All of far side pupil should not show.
Smile: - As broad a grin as possible, with the teeth showing. Otherwise similar to frontal view. www.indiandentalacademy.com
INTRA-ORAL PHOTOGRAPHY www.indiandentalacademy.com
INTRAORAL VIEWS ď Ź
The basis of an excellent clinical photograph is clean and accurate rendering of the subject area free of visually distracting influences such as saliva or material (alba) or of the poor use of mirrors, retractors, or backgrounds.
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POSITIONING THE PATIENT The position of the patient is important to the camera view and to the operator’s ease in making the view . For most straight anterior views, the patient should be in a semi upright position with a slight tilt backwards. In a contour chair, the patient must turn his head to the side so that the operator does not have to lean sideways over the chair and patient.
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MIRROR VIEWS ď Ź
Maxillary Arch : For ease in making intra oral views of the maxillary arch, the patients head should be slightly titled back.
ď Ź
Mandibular arch : The head must be tilted back far enough to allow this arch to be almost parallel with the floor when the mouth is wide open. www.indiandentalacademy.com
OPERATORY DENTAL LIGHT It should not be directly on the teeth. Keep the light on the side of the cheek and out of the mouth. The light is only needed to give enough light to focus by. When the dental light is bright or strong on the side of the arch that should have the greatest contrast, it will kill the contrast produced by the flash.
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DEPTH OF FIELD Focus should be on the particular lesion or tooth for close-up views. For full mouth views, focus should be just ahead of half the anterior posterior distance. In most views, this would be cuspid midline to first bicuspid midline. At this point of focus, depth of field will produce anterior-posterior sharpness.
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POINTS OF INTEREST
The slide image should include only main points of interest. The camera should be in close enough. Exclude retractors, mirror edges, fingers, and above all the patient’s lips when not wanted as a part of the scene.
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APERTURE CONSIDERATIONS The f-opening will depend on the film speed, power of the flash, and its position on the bracket. The correct f-opening is - (f/22) for an area of six anterior teeth. Intraoral views for black people should use one half stop more open (f/19). Pure white subjects (enamel) require less light, so these views should be f/27.
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With all adjustments considered, to make the final exposure, move the camera forward (the automatic lens is wide open) to see the area selected. It will only be sharp in a narrow band (one tooth) as the lens is wide open. Adjust the camera attitude to the patient’s position to minimize movement of the camera. Keep your arms close to the body, or rest your elbow on any handy support. Ensure it is stable and then press the shutter
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Intra oral lighting and contrast
With a side-mounted 180º rotation to the flash, the lighting and contrast can be changed for each scene. Ninety percent of all intraoral views should be made with the flash at 9 or 3 o’clock. Generally, never use the flash at 12 o’clock . For some views in the lower arch or under the tongue with the tongue held up, you may want the flash used at from 11 to 1 o’clock. www.indiandentalacademy.com
How to determine the best position of the flash for the teeth and for other details? www.indiandentalacademy.com
ď Ź Whatever
side of the arch the flash is directed onto will always have the least shadow or contrast, but it still will be adequate. www.indiandentalacademy.com
ď Ź
For greater contrast to the six anterior teeth, to show enamel texture or detail, remove the flash from the bracket and hold it at a 45’ angle so that it will cross-light the anterior teeth. www.indiandentalacademy.com
RETRACTOR SHAPES
Because the size of mouths vary, more than one pair of retractors should be available. Do not hesitate to modify or cut down your own retractors for special applications. Curved metal wire retractors have some applications and should be used when needed. The main application for this retractor is buccal mirror views. www.indiandentalacademy.com
Application of retractors : ď Ź
Too often, retractors are placed on the lip, and the patient or assistant is then asked to hold them and proceeds to retract the lips by pulling the handle back toward the ears. www.indiandentalacademy.com
Application of retractors : If the patient’s mouth is very small and the lips very tight, one retractor can be used for right or left buccal views, then a small retractor on the other side can be used just to keep the lips apart soothe flash can illuminate the area well. Where plastic or wire retractors cannot be used for views such as a lip lesion, fingers can be used to stretch the lip or extend the frenum.
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Mirrors : The use of glass mirrors that have been rhodium-plated on one or both sides has been recommended . ď Ź Metal mirrors are not satisfactory ; they have neither the brilliance nor smooth surface of a glass mirror. ď Ź
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MIRROR SHAPES AND SIZES ď Ź
There are three standard mirrors, sold as the University of Washington set.
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MIRROR SHAPES AND SIZES ď Ź
Other shapes are available for special purposes.
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PLACEMENT OF MIRRORS
MAXILLARY ARCH:-Patient’s head should be slightly tilted back. -Warm the mirror to prevent fogging. -The finger and thumb should be on the peripheries which will keep them from appearing in the photograph. www.indiandentalacademy.com
MAXILLARY ARCH:ď Ź Occlusal ViewThe posterior part of the mirror should rest on the distal cusps of the last tooth, with the mirror centered in the arch and held at about a 450 angle. ďƒ˜
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ď Ź
If the mirror is held at too steep an angle, a view of the nostrils will also be included.
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MAXILLARY ARCH: Buccal ViewThe buccal mirror should always be placed distally to the area to be viewed and should be held as close to a 450 angle to the buccal surfaces of the teeth as possible.
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1.
MAXILLARY ARCH:-
Palatal ViewFor lingual views of the six anterior teeth, mirror should be at 45º angle to the occlusal plane. If the mirror is held at too steep an angle, a view of the nostrils will also be included.
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ďƒ˜ MAXILLARY
ARCH:-
2. For the posterior lingual view, the mirror must be at about a 45Âş angle and as far as possible away from the area to be viewed. The mirror should not touch the lingual side of the last molar, but it should be close. The mirror should then angle across the arch so that it crosses over the first or second bicuspid as it comes out of the mouth. www.indiandentalacademy.com
ďƒ˜
MANDIBULAR ARCH :In general, the same procedure is followed for the mandibular arch, except that the head must be tilted back far enough to allow this arch to be almost parallel with the floor when the mouth is wide open. www.indiandentalacademy.com
BACKGROUND AND LIGHTING FOR OBJECTS ď Ź 1. 2. 3.
Things to be considered:Texture Color How the background is to be used? (flat paper or curved to form a floor and a wall)
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ď Ź
TEXTURE:* Paper should be smooth and dull. - For burrs and instruments- minimum textures - For casts, specimens – colored crepe paper. * Cloth is a bad background as it has too much texture.
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ď Ź
COLOR:-Background color should be a light pastel for color photography. - Dark colors distract from the importance of the subject. - For white casts -> black paper.
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ď Ź
HOW TO USE THE BACKGROUND? * Paper should be curved, not creased. - Eliminates line of horizon . * Wall provided,should not be far from object.
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PHOTOGRAPHY OF SMALL OBJECTS APERTURE- Pure white -> f/27 - Other color -> f/19, f/22 - Black -> f/15. Use proper background and lighting. - Use flash at 12 o clock position to eliminate shadow.
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PHOTOGRAPHY OF SMALL OBJECTS ď Ź
Wet or dry small specimens :Glass plate working surface.
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PHOTOGRAPHY OF LARGE OBJECTS
DENTAL CASTS:# Background – - Black for white casts. # Flash – - 12 o clock position to prevent shadows.
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ď Ź
If light source is either on left or right, then a small white paper reflector can be used.
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DIGITAL CAMERAS www.indiandentalacademy.com
BASIC TERMS Graphic Applications Pixels arranged in horizontal ‘Raster Lines’. Display Resolution. expressed as display width by display height in Pixels.
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BASIC TERMS Bitmap. Image Resolution and dots per inch(dpi). Bits. Sample Depth. 24 bits of data per pixel – 16.7 m colors. For RVGs also at least 8 bit palette color format needed which gives 256 shades of gray.
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PRINCIPLE EMPLOYED It captures the image on a CHARGED COUPLE DEVICE ( C.C.D). The finer the grid of the C.C.D the greater is the amount of detail recorded. The basic unit of image detail is known as ‘PIXEL’ (picture element).
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ADVANTAGES OF ‘DIGICAMS’ 1.
2.
3. 4.
Speed and immediacy of image capture, immediate review and re exposure of unsatisfactory images. Cataloguing and storage of images is simplified with associated computer system. Incorporation of images into documents and presentations is simplified. Images can be cropped too. www.indiandentalacademy.com
DISADVANTAGE It can not replace the need of a 3-D dental casts. Although CAD – CAM technology has arrived , but until a truly 3-dimensional digital replica is available, dentists should continue to keep plaster casts for medicolegal records.
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In a review by Hutchison et al (1999) Highest resolution -->1280 x 1024 pixels more conveniently known as 1.3 Megapixels. Rapid advancement in technology. higher no. of pixels :. Increase in amount of detail found. Latest cameras have 5, 6.5, 11.1 Megapixel resolution. Now the quality of images is more than acceptable.
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FEATURES TO CONSIDER
LIQUID CRYSTAL DISPLAY (LCD) MAINS ADAPTOR SOFTWARE RESOLUTION NUMBER OF IMAGES STORED INTERNALLY.
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PRACTICAL CONSIDERATIONS Downloading of images Reproduction Storage and filing Batteries Radiographs
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FOVEON CHIPS
Conventional cameras use CCD chip with many pixels. Pixels insensitive to light. Pixel covered – filter. In FOVEON CHIP, 3 filters stacked on 1 another. www.indiandentalacademy.com
CONCLUSION In photography you should be clear with your basic fundamentals and you should know how to apply them aptly in a given situation. So ,lets just not ‘take pictures’ , lets
MAKE PHOTOGRAPHS www.indiandentalacademy.com
REFERENCES The ABC’s of picture taking ease with EOS cameras. Practical Photography. World book. Dental Clinics of North America; 1983. BJO;1999; Vol 26 BJO; 2000; Vol 26 AJODO;2004;125;139.
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