IT'S ALL ABOUT LIGHT
The main purpose of photography in dentistry is documentation. The aim is to capture as much information as possible under reproducible conditions. For this purpose, the camera used, its accessories and the format and illumination of the intraoral and extraoral images relevant to dentistry must be standardized. The definition of current standards includes the following aspects: Equipment, settings, recording protocols, infection prevention as well as image processing and archiving. In this article we would like to go into more detail about the selection of your camera and what you should pay attention to when buying it.
WHAT CAMERA DO I NEED?
Today, a wide variety of cameras and pho- tographic accessories are available on the market. For dental use, the quality of the images is crucial, as, in terms of medical law, the photographs taken are similar to X-ray images. This factor should be taken into account when selecting equipment.
Compact cameras, intraoral video cameras and smartphones can only be used to a limited extent for standardized recordings because the built-in lenses only allow a shallow depth of field, the magnification is not defined and there are often problems with correct colour reproduction.
In dental photography, the gold standard is a digital SLR camera with a suitable macro lens and an associated flash system
(Fig. 1). Such equipment makes it possible to take high-quality photographs and, if necessary, to access a large selection of accessories.
DSLR VS MIRRORLESS
You can get great photos with either a DSLR or a mirrorless camera, but each has its pros and cons. DSLRs use the same design as the 35 mm film cameras from the past. A mirror inside the camera body reflects the light coming in through the lens up to a prism, and into the viewfinder for you to preview your shot. When you press the shutter button, the mirror flips up, a shutter opens and the light falls onto the image sensor, which captures the final image.
In a mirrorless camera, light passes through the lens and right onto the image sensor, which captures a preview of the image to display on the rear screen. An electronic viewfinder replaces the optical viewfinder found on DSLR cameras.
The electronic viewfinder can be a real relief at work, in particular with focus peaking activated. Especially for eyeglass wearers, this is an improvement. Focus peaking works by detecting edges of highest contrast in your image (and therefore most in focus) and highlighting them in a bright color, usually of your choice. This sounds very similar to the contrast-detect-focusing function found in many cameras and, in a way, it is. The camera will use red, blue, green, white, yellow, or another color that
allows photographers to recognize what is in focus and what isn’t, since it will be contrasting with the normal colors of the scene. (Fig. 3).
It may sound surprising that this feature has taken so long to make it from video cam- eras to still cameras, but there is one very important reason: it requires processing of the live image from the sensor in real time and a screen on which to view it. For years SLRs and rangefinders dominated the scene with their optical viewfinders, but with the emergence of mirrorless cameras and the use of high-quality electronic viewfinders, manufacturers have been able to add nu- merous features that were not possible with the simple OVF. DSLRs can also benefit from focus peaking through the implementation of Live View and articulating screens that permit composing and focusing using the LCD on the rear of the camera.
In the digital workflow, the individually configurable wifi data transfer has proven to be extremely useful. It is possible to define a specific folder on the computer to store the images.
The only downside of mirrorless cameras is that macro lenses are not yet available for all cameras and therefore oftentimes a lens adapter is required. But these adapters work without any problems. Existing flash systems also work fine with mirrorless cameras.
If you want to get into dental photography today and do not yet have any equipment, it is worth taking a look at mirrorless cameras. But DSLR cameras and the corresponding accessories will surely be available for some years to come.