| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Clinical Section |
1 Outpatient Suite 2, Royal Hospital, Chesterfield, UK
2 Derbyshire Royal Infirmary, Derby, UK
Abstract
A brief history of digital photography is provided along with a critical appraisal of the ‘prosumer’ and professional systems currently available. Recommendations are made as to the system best suited to current orthodontic practice.
Key words: Digital, Photography
Introduction
Photographs are an essential part of clinical documentation. Current ‘best practice’ is a full set of extra- and intra-oral photographs, both at the start and completion of a course of orthodontic treatment and, ideally, some mid-treatment photographs showing key-stages in treatment (Sandler, 2000
).
Digital photography has been generally available since 1981. In 1991 ‘Autotrader’ were the first mass market publication to move completely to digital recording of images. Now, many trades and professions, including estate agents, advertising agencies, police, and the media use digital photography on a routine basis.
Digital images are made up of picture elements (‘pixels’) comprising red, green, and blue light, each set at a level between 0 and 255. If all three colours are set at 255 white is the result, while if all are set at zero, black results (Figure 1). There are 256 grey shades that result from all three colours being set at the same number. Varying the level of each of the three colours results in the gamut of 16•7 million colours. Numerical values for each of these colours are stored on the Charged Couple device (CCD). This is made up of pixels, the number of which, combined with the degree of compression, determines the quality of the final output.
|
). By 1999 the first ‘mega-pixel’ cameras (over 1,000,000 pixels per image) were becoming available, but above 1•5 megapixels the law of diminishing returns kicked in with a disproportionate price increase for only modest improvements in quality.
|
), and was relatively inexpensive. However, well-recognized problems with conventional photographic techniques are the cost of developing and processing films, the time required for processing and physical storage of all the patients slides or prints.
‘Prosumer’ cameras
One type of digital camera (prosumer) falls into the mid-range price bracket £500–1500 and lies between the consumer camera and the professional models. They usually have a host of useful features including macro-zoom lenses and potentially high image quality. The ‘piece de resistance’ of digital cameras is undoubtedly the image preview facility in that images can be immediately viewed on the LCD screen and accepted or, if flawed, deleted and retaken.
The problems with the ‘prosumer’ cameras used for orthodontic photography are three-fold.
First, the flash provided with most digital cameras is a point flash. Experience has shown that for high quality intra-oral images ring flashes are essential to avoid unacceptable shadowing on most of the images (Figure 3). Despite the use of deflectors and diffusers the results with the built-in point flash tend to be disappointing. The point flashes are also not powerful enough to allow the photos to be taken on very small apertures (F32). This is essential as it greatly increases the depth of field and ensures most of the frame is in focus. In addition, even if it is possible to add a ring flash to the ‘prosumer’ camera high quality consistently exposed images require through the lens (TTL) metering, which is not available on these ‘lower end’ systems. After 20 years of ever increasing quality of orthodontic photography using SLR systems, TTL metering, and ring flashes, some of the orthodontic community are accepting mediocre photographs, taken with substandard digital equipment just for the facility of immediate viewing.
|
). Turning the camera around on buccal intra-oral shots may also reduce shadowing to a degree.
|
Thirdly, the focusing system can be problematic as the auto-focus systems on the ‘prosumer’ cameras are frustrating to work with when capturing intra-oral photographs. They often take three or four attempts to get the system to focus adequately, and all the area of interest is not always as sharp as it might be. The predetermined distance ‘macro’ settings available on some of the digital cameras also sometimes give disappointing results.
Professional cameras
Top end cameras have always been available. Indeed, Kodak teamed up with Nikon in the late 1990s to produce the Digital Camera System (DCS), which was capable of very high quality images. The problem with this system was that the camera body alone was over £10,000 (Figure 5).
|
). Also The SB29 ring flash does not work as TTL metering with this body. Finally, a price tag for the whole package of close to £5000 makes it unaffordable for many clinicians.
Another digital camera recently released is the Fuji FinePix S1 Pro, which may be the perfect digital camera for orthodontics (Figure 6). The body is made by Nikon and is therefore built to a high specification. The lens system required is the Nikon 105 mm/2•8 AF Macro and the flash system is the Nikon SB29 Speedlight. The flash provides TTL metering and, therefore, the intra-oral photos taken at F32 are invariably perfectly exposed and in focus. The pictures are all taken on manual focus just by setting the lens adjustment for intra-oral shots, then moving backwards and forwards to focus. Using the ‘limit’ switch on the lens allows the same magnification to be set for all intra-oral photos, thus allowing direct comparability between photos.
|
). The images can still be cropped and enlarged as necessary retaining sufficient detail for most situations.
|
The system has been in use in the Orthodontic Departments of Manchester University and Chesterfield Royal Hospital with 13 postgraduates using the system on a daily basis since October 2000, and the system is working very well so far. Before October, monthly bills for developing and processing at Manchester were approximately around 
390 per month. It was evident that the digital camera would pay for itself in a reasonably short time, after which the photography will be ‘free’.
Conclusions
Digital photography offers many advantages including:
The second paper in this series will detail a system for storage, manipulation, presentation, and transmission of the clinical images.
Notes
References
Sandler P. J. (2000)Profiting from photography,Angle Society Newsletter, pp. 26–27.
Sandler P. J. and Murray A. M. (1999) Recent developments in clinical photography, British Journal of Orthodontics, 26, 269–274.
This article has been cited by other articles:
|
|
 |
|
  D. Bister, F. Mordarai, and R. M. Aveling Comparison of 10 digital SLR cameras for orthodontic photography. J. Orthod., September 1, 2006; 33(3): 223 - 230. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Lowe and J. Sandler How to do ... a case report J. Orthod., June 1, 2002; 29(2): 143 - 147. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
