CLINICAL PHOTOGRAPHY.ppt USEFUL FOR DENTAL STUDENTS

CLINICAL
PHOTOGRAPHY

CONTENTS
oINTRODUCTION
oCAMERAS AND PARTS
oLENSES
oSHUTTER
oAPERTURE
oEXPOSURE
oFILM
oLIGHTING
oFOCUSING
oCLINICAL TECHNIQUES
oDIGITAL PHOTOGRAPHY
oCONCLUSION

INTRODUCTION
1
st
camera –Italy
‘CAMERA OBSCURE’ (dark chamber)
Huge box with a tiny opening on one side.
On the opposite side light formed an
inverted image.

CAMERA
BODY
LENS
SHUTTER
VIEW-FINDER

PRINCIPLE EMPLOYED IN CAMERA
The camera works in
much the same way
as our eye.
Shutter –eye lid
Aperture –iris
Lens-lens
Film-retina

TYPES OF CAMERAS
# Sheet Film Cameras
# Non-Reflex Cameras
-Snap Shot Cameras
-Range Finder
Cameras

TYPES OF CAMERAS
# Disc Cameras
# Cartridge Load
Cameras

TYPES OF CAMERAS
# Instant Picture
Cameras

TYPES OF CAMERAS
# Twin Lens Reflex
Cameras

TYPES OF CAMERAS
# Single Lens Reflex
Cameras

TYPES OF CAMERAS
# Panoramic Cameras
# Underwater Cameras
# Stereographic Cameras
# Aerial Cameras
# Electronic Cameras.

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.

PHYSICS IN LENSES
REFRACTION-The
bending of light on
entering a different
transparent medium.
REFRACTIVE
INDEX-The bending
power of the medium.

LENSES
Series of prisms
stacked up.

ABERRATIONS IN LENSES
Spherical Aberrations
Chromatic
Aberrations

FEATURES OF LENSES
Covering Power of a Lens-
The 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.

FEATURES OF LENSES
FOCAL LENGTH AND
MAGNIFICATION-
Focal Length is the distance from the
lens
to the film to get a sharp image of an
object.

•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

DEPTH OF FIELD
Zone of in focus
elements from front to
back.

TYPES OF LENSES
STANDARD LENSES
WIDE ANGLE LENSES
TELEPHOTO LENSES

DRONACHARYA’S TEST

TYPES OF LENSES
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.

TYPES OF LENSES
WIDE ANGLE
LENSES-
-Provide maximum
amount of depth of
field.
-Background seems
farther away.
Foreground is in
focus.

TYPES OF LENSES
TELEPHOTO
LENSES-
-Magnified
images ,fill the
frame with the
subject.
-Focal length
more than that of
the lens.

TYPES OF LENSES
FISH EYE LENSES
ZOOM LENSES

TYPES OF LENSES
SPECIAL LENSES
•Night lenses
•Shift lenses
•Macro lenses
•Medical lenses

SHUTTER
Earlier-no shutters were used.
Because people used very slow light
sensitive materials, which required
exposure of several minutes.
PURPOSE-
To protect the film from light until the
chosen moment.

TYPES OF SHUTTERS
Leaf Shutter-
built into lens.
no.of thin metal
plates.

TYPES OF SHUTTERS
Focal Plane Shutters-
-Essential in S.L.R
cameras.

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.

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

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.

APERTURE
Lower the number
greater the aperture
size and vice-versa.

Aperture and Area of
sharpness.
SMALL aperture-little
light-render subject
sharply.
LARGE aperture-
more light-captures
shallow plane clearly.

EXPOSURE
It is the total amount of
light that reaches the
film in the camera.
i.e. intensity of light x
time.

EXPOSURE
Proper exposure
depends upon:-
-Lighting
-Subject
-Desired depth of
field.

Each of these require an
adjustment in :-
-shutter speed or
-aperture size

FILM
3 main types:-
Black and white
Color
Color reversal films (color slides).

LAYERS OF A BLACK AND WHITE
FILM
1.Scratch resistant
coating
2.Emulsion layer
containing silver
halide crystals in
gelatin.
3.Plastic film base.
4.Anti-halation
coating.

LAYERS OF A COLOR FILM
1.Scratch resistant coating
2.3 Emulsion layers containing dyes
sensitive to blue,green and red colors in
gelatin.
3.Plastic film base.
4.Anti-halation coating.

COLOR REVERSAL FILMS
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.

CHARECTERISTICS OF A FILM
1.SPEED
2.GRAININESS
3.COLOR SENSITIVITY
4.COLOR BALANCE

LIGHTING
3 sources of man made
light:-
Incandescent
Vapour Flash
Electronic Flash

FLASH TECHNIQUES
Bounce the Flash –
Indirect lighting
Fill in flash or
Synchro sunlight –
Direct lighting

DIRECTION OF SOURCE OF
LIGHT
1.FRONT LIGHTING
2.BACK LIGHTING
3.SIDE LIGHTING
4.TOP LIGHTING
5.BOTTOM LIGHTING
6.MULTIPLE LIGHTING
7.MIRRORS
8.ULTRAVIOLET LAMPS
9.LASERS

HOW TO MAKE A
PHOTOGRAPH?

BALANCE OF THREE ELEMENTS
1.SHUTTER SPEED
2.APERTURE VALUE
3.FILM SENSITIVITY

SHUTTER SPEED
Fast shutter speeds
keep both fore ground
and background in
sharp focus.

APERTURE VALUE
Wide aperture -
Minimum DOF
Stopped down
aperture –Max DOF

CLINICAL
ASPECT

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).

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.

EXTRA ORAL
PHOTOGRAPHY

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)

IDEAL HEAD POSITIONS
Frontal view:-
-outer canthus to
superior attachment
of the ear (C-SA
line);
-Interpupillary line;
-Encompassing
area (crown to
collarbone).

IDEAL HEAD POSITIONS
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.

ABO Requirements
1.Quality prints either in black and white or
color.
2.Head oriented accurately in all 3 planes
of space and in F-H plane.
3.1Lateral view-facing to the right ,
serious expression ,lips closed lightly.
4.1Anterior view-serious expression
5.Background free of distractions.

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.

Camera position for lateral view

Hairstyle:
Hairstyle can distract
from facial analysis.
Hair should be pulled
back, in a ponytail, if
necessary.
This allows for
auricular analysis and
for relationship
between tragus and
infraorbital rim to be
evaluated.
Same applies to hair

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.
IDEAL HEAD POSITIONS

INTRA-ORAL
PHOTOGRAPHY

INTRAORAL VIEWS
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.

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.

MIRROR VIEWS
Maxillary Arch :
For ease in making intra oral views of the
maxillary arch, the patients head should
be slightly titled back.
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.

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.
.

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.

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.

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.

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
release.

Intra oral lighting and contrast
With a side-mounted 180ºrotation 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.

How to determine the
best position of the
flash for the teeth and
for other details?

Whatever side of the arch the
flash is directed onto will
always have the least shadow
or contrast, but it still will be
adequate.

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.

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.

Application of retractors :
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.

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.

Mirrors :
The use of glass mirrors that have been
rhodium-plated on one or both sides has
been recommended .
Metal mirrors are not satisfactory ; they
have neither the brilliance nor smooth
surface of a glass mirror.

MIRROR SHAPES AND SIZES
There are three
standard mirrors, sold
as the University of
Washington set.

MIRROR SHAPES AND SIZES
Other shapes
are available
for special
purposes.

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.

MAXILLARY
ARCH:-
Occlusal View-
The 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 45
0
angle.

If the mirror is held at
too steep an angle, a
view of the nostrils
will also be included.

MAXILLARY ARCH:-
Buccal View-
The buccal mirror
should always be
placed distally to the
area to be viewed and
should be held as
close to a 45
0
angle
to the buccal surfaces
of the teeth as
possible.

MAXILLARY ARCH:-
Palatal View-
1.For 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.

MAXILLARY ARCH:-
2. For the posterior lingual view, the mirror
must be at about a 45ºangle 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.

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.

BACKGROUND AND LIGHTING
FOR OBJECTS
Things to be considered:-
1.Texture
2.Color
3.How the background is to be used?
(flat paper or curved to form a floor
and a wall)

TEXTURE:-
* Papershould be smooth and dull.
-For burrs and instruments-minimum
textures
-For casts, specimens –colored crepe
paper.
* Clothis a bad background as it has too
much texture.

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.

HOW TO USE THE
BACKGROUND?
* Paper should be
curved, not creased.
-Eliminates line of
horizon .
* Wall
provided,should not
be far from object.

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.

PHOTOGRAPHY OF SMALL
OBJECTS
Wet or dry small
specimens :-
Glass plate working
surface.

PHOTOGRAPHY OF LARGE
OBJECTS
DENTAL CASTS:-
# Background –
-Black for white
casts.
# Flash –
-12 o clock position
to prevent shadows.

If light
source is
either on left
or right, then
a small white
paper
reflector can
be used.

DIGITAL
CAMERAS

BASIC TERMS
Graphic Applications
Pixels
arranged in horizontal ‘Raster Lines’.
Display Resolution.
expressed as display width by display
height in Pixels.

BASIC TERMS
Bitmap.
Image Resolution and dots per inch(dpi).
Bits.
Sample Depth.
24 bits of data per pixel –16.7 m colors.
For RVGsalso at least 8 bit palette color
formatneeded which gives 256 shades of
gray.

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).

ADVANTAGES OF ‘DIGICAMS’
1.Speed and immediacy of image capture,
immediate review and re exposure of
unsatisfactory images.
2.Cataloguing and storage of images is
simplified with associated computer
system.
3.Incorporation of images into documents
and presentations is simplified.
4.Images can be cropped too.

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.

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.

FEATURES TO CONSIDER
LIQUID CRYSTAL DISPLAY (LCD)
MAINS ADAPTOR
SOFTWARE
RESOLUTION
NUMBER OF IMAGES STORED
INTERNALLY.

PRACTICAL CONSIDERATIONS
Downloading of images
Reproduction
Storage and filing
Batteries
Radiographs

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.

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

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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CLINICAL PHOTOGRAPHY.ppt USEFUL FOR DENTAL STUDENTS

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CLINICAL PHOTOGRAPHY.ppt USEFUL FOR DENTAL STUDENTS

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