Digital photography

RECENT ADVANCES
IN DIAGNOSTIC AIDS
www.indiandentalacademy.com

DIGITAL PHOTOGRAPHY

Dental photography
• Patient education
• Legal record for facial features before and after
dental treatment
• Excellent tool for teaching
• Excellent tool for communication

Digital photography
• Basics of digital photography
• Classification of digital cameras
• Features to consider in digital cameras
• Conventional versus digital photography
• Common errors in clinical photography
• Gold standard in clinical photography

Basics of digital photography
• First used in 1981
• Commercially available since 1991(marketed
by auto trader).

Digital images
• Pixels – picture elements

green
bluered

• Pixelation evident

• Resolution – no of pixels in the image.
• Increase in pixels – increases the detail of the
image.

Non film cameras
IMAGE SENSORS
- CCD ( CHARGED COUPLED DEVICE)

- CMOS (complementary metal oxide
semiconductors)
Non film cameras

HOW THEY WORK

KNOW YOUR DIGITAL CAMERA

Lens
Telephoto lens Macro lens

Lens
• Rotatable

Shutter speed
• Shutter speed – the length of time the shutter
is open and light strikes the image sensor
• Bright lens and high shutter speed – ideal
• Higher shutter speed – grater the image quality
• Cameras should have a range of high and low
shutter speeds.

Burst
• Sequential shooting
• Overcome shutter lag

White balance
• Used to keep color as natural as possible.
• Level of one color is more camera adjusts
automatically.

Exposure
• Amount of light required to take a photo.
• Too much light
• Less light.

Exposure compensation

Flash
• Adjustment for convenience
• Ring flash

Flash
Ring flash

Zoom
• Must in any digital camera
• Closer to the subject without moving
physically closer.

Focal length
• The distance between the rear nodal point of the lens and
the focal plane when focus is set at infinity.
• Nodal point – where the rays of light appear to have come
after passing through the lens.

• HOW MUCH THE CAMERA SEES ( ANGLE OF
VIEW OF THE LENS).

ZOOM
• OPTICAL ZOOM
• DIGITAL ZOOM

Optical zoom
• Zoom lens is lens determined so that its focal length
can be varied over a predetermined range.
• The image is optically modified so that it can show a
smaller o larger field of view.
• This allows to replace a no of single focal length
lenses.

• Does not change the resolution of the image or
the image size, the no of pixels used to
describe the image are same.

Digital zoom
• Digital cameras with a single focal length lens.
Offers possibility of mimicking a zoomed
image.

• No of pixels used to capture a image are the
same as original non zoomed image.

Difference between optical and
digital zoom
• Optical zoom – bring object closer ( like a
telescope)
• Digital zoom is merely a cropping tool.

Confusion
• for eg- 10 x optical zoom becomes 60 x if 6x
digital zoom is tacked on the focal length of
the lens.

• Smart zoom

Aperture settings
• AMOUNT OF LIGHT ENTERING THE CAMERA
AND HITTING THE SENSOR.

Depth of the field
• THE AREA AHEAD OF AND BEHIND THE AREA
IN FOCUS.

Digital cameras
CLASSIFICATION
• CONSUMER
• PROSUMER
• PROFESSIONAL

• Inexpensive
• Entry level
• Mid range
• High end
• Professional.

Prosumer
• Lies between consumer and professional
cameras.

• Features – macro lens

• Features – High quality image

• Features –Lcd with preview facility

Drawbacks
• FLASH – POINT FLASH.
- RING FLASH

Drawbacks
VIEW FINDERS – GALLILEAN TELESCOPE VIEW FINDER
- LCD

Drawbacks
FOCUSING SYSTEM – LACK OF IMAGE SHARPNESS

Professional cameras
• Expensive
• High end features.
• Ideal for intra oral photography.
• Fuji fine pix f1 pro – perfect for orthodontic
purposes.

Features to be considered

• LCD

MAINS ADAPTOR

AUTO FOCUS AND PRECISION

• CCD RESOLUTION AND QUALITY
• CUR ( clinically useful resolution)

• FLASH CAPABILITY

Exposure parameters
• Lens opening
• Shutter speed( lens opening in fraction of a
second)

• SOFTWARE

• RESOLUTION

Practical considerations
• DOWNLOADING OF IMAGES

• REPRODUCTION
• STORAGE AND FILLING

• BATTERIES

ACCESSORIES
• MEMORY CARDS

• BAGS AND STRAPS
• TRIPODS
• CLEANING KIT
• CARD READER

CONVENTIONAL VERSUS
DIGITAL PHOTOGRAPHY

NON FILM CAMERA

IMAGE STORAGE

NO RECURRING COSTS

ROOM FOR EXPERIMENTATION

FUNCTIONALITY IN A SMALL
PACKAGE

LCD ELIMINATES GUESS WORK

DURABILITY

SCALABILITY

SHARING

DRAWBACKS
• HIGH INITIAL COST

• BATTERY LIFE

• NON STANDARDIZATION
• LEARNING CURVE
(Technophoia).

COMMON ERRORS IN
CLINICAL PHOTOGRAPHY

Two groups
• Inappropriate choice of equipment.
• Errors in recording medium and inappropriate
positioning of subjects

Camera
• Macro facility ( 1:1 images)

Camera
• Ring flash

Camera
• Orientation of camera
– Extra-oral ( portrait)
– Intra oral ( landscape)

Camera
• Lens setting

Retractors
• Two set of double ended retractors

INTRA ORAL SHOTS

BUCCAL SHOTS

OCCLUSSAL SHOTS

MIRRORS
• LONG HANDLED AND FRONT SILVERD GLASS
- IDEAL

REAR SILVERED VERSUS
FRONT SILVERED GLASS

MIRRORS

APERTURE COMPENSATION

TECHNICAL PROBLEMS
• DEPTH OF FIELD

• PROSUMER CAMERAS – APERTURE TO BE
REDUCED TO F 11.

• APPROX 1/3 IN FRONT AND 2/3 BEHIND THE
FOCAL POINT

Professional cameras

Auto focus problems
• Auto focus versus manual focus

Intra oral

• FOCUSSING USING TTL FACILITY.
• 20 CM IS A GOOD DISTANCE.

Extra oral photography

SHADOW
• POINT FLASH

EXTRA ORAL

Extra- oral

Alternatives
• Rotating camera through 1800
• Illuminated backdrop screen
• Dark non reflective background preferably
velvet

INTRA ORAL

Overcoming shadows – 1800
turning

OCCLUSSAL

Solution- focus away from
patient

SYMMETRICAL IMAGES
• GRID LINES

CARD PROBLEMS

CCD ROBLEMS

DIGITAL IMAGE
• FIT FOR PURPOSE

POSITIONING ERRORS

Extra oral photographs
• Portrait

• Background

PROFILE AND THREE QUARTER
VIEWS

INTRA ORAL PHOTOGRAPHS
• LANDSCAPE VIEW

• Change in cant of occlusal plane

• Inappropriate selection of cheek retractors.
• Saliva not aspirated

BUCCAL VIEWS

MIRROR VIEWS
• OCCLUSSAL SHOTS

Just one more photograph

LCD

Standardizing dental photography
• Natural head position.
• Frontal views.
• The line from the outer canthus of eye to
superior attachment of ear from should be
parallel to Frankfort horizontal plane.
• The inter pupilary line should be parallel to
horizontal plane
• The distance from outer canthus of eye to the
hair line should be equal on both side

CAMERA LENS AND POSITION
• Focal length of the lens should be the same
(100 or 105mm)

• Have consistent subject – camera distances
(use of tripod)

• Camera position is one in which a line from
middle of lens to eye is parallel to horizontal
plane

GOLD STANDARD IN
PHOTOGRAPHY
• Journal of orthodontics june 2002
- j sandler and a murray

• Survey carried out in angle society.
• Seventy questionnaires were used
• Following questions were asked.
– which intraoral and extraoral photographs they currently take?
– when during the treatment the photographs are taken?
– which staff member takes the photographs?
– what medium is used to record the images?

Routine use of photography
96% take pre and post treatment photographs.

Intra oral photographs

mid treatment photographs

Who takes the photographs?

Photographic medium

Gold standard
• Nine pretreatment and nine post treatment
photographs are a must.
• mid treatment photographs at change of every
arch wire .
• Up to 36 photographs are considered a
reasonable number for full photographic
documentation of the case.

Need for photographs
• Extra oral
full face view ( lips at rest )

• Extra oral
– full face view ( smiling)

• Extra oral
– three quarter view

• Extra oral
– profile view

• Intra oral
front intra oral view.
buccal intra oral shots.
upper and lower buccal shots.
overjet view ( optional ).

Orthodontics current principles
and techniques - GRABER AND VANARSDALL

Conclusion

Digital photography

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