Ferdi Chum shares some of his experience and knowledge on dental photography for dentists.
The Basics
For most newly qualified dentists who are eager to improve and elevate their dentistry on a limited budget, there are lots of factors to consider when deciding how to allocate limited resources towards developing their career.
Dental photography is one of the key pillars that helps us springboard our quality of care. It allows us to analyse our treatment outcome, our workflow process, and also critique our shortfalls / strengths.
Apart from loupes, a good camera set up is probably one of the most expensive investments we make early on in our careers.
The Camera Setup
The Body
DSLR vs Mirrorless
The DSLR is probably the most common professional device used in photography. In simple terms, it operates by a mirror within the body that reflects the light to the viewfinder. When we capture the photo, the mirror moves out the way, exposing the sensor to the image and capturing it.
A mirrorless body is essentially the same as the DSLR, but the mirror mechanism is removed and the sensor itself acts as a real-time digital viewfinder. It is significantly smaller, thinner, and lighter. Without this mirror mechanism, the body is also significantly faster and more intelligent. Traditionally, mirrorless cameras are more expensive than DSLRs, but this is not necessarily the case anymore.
Full Frame vs Crop Frame
This refers to the sensor size of the body. Full frame effectively means the sensor is 36 x 24mm, the size of a traditional 35mm film camera. Crop frame in general is 1.6x smaller. Crop frame bodies tend to be smaller and lighter. They are subjected to crop factors, which play a significant role in dictating the lens selection. Without considering this when investing in your equipment, it can make your set up very difficult to use.
*Mirrorless cameras are better than DSLRs but are more expensive. Full frames are better than crop frames but are more expensive and heavier.
The Macro prime lens
The lens must have the ability to focus on objects that are very close. In other words, it must be a macro lens. A macro lens can produce 1:1 magnification, meaning if the lens is capturing an object of 1cm in size, it will produce an image of that object on the sensor that is also 1cm in size.
100mm vs 85mm vs 60mm
This is where the crop factor the body plays a huge role. If we use a 100mm focal length macro lens on a full frame body, the image produced would be very different from the image produced by a crop frame body. To compensate for this, a shorter focal length lens must be used. Using a 60mm prime macro lens on a crop frame would produce an image similar to an image produced by a 100mm on a full-frame.
In dental photography, we are standing relatively close to our patient, therefore using a 100mm lens on a crop frame we will have to stand far from our patients, making the set up not ideal. On the contrary, if we use a lens with too short of a focal length i.e., a 60mm on a full frame, we will be standing too close to our patient, as well subjecting our photos to lens distortion known as barrel distortion.
*Use a 100mm macro lens on a full-frame body and use either a 60mm or an 85mm on a crop-frame body. DO NOT PURCHASE ZOOM LENSES FOR DENTISTRY.
The Flash
Ring flash vs Twin flash
I am a firm believer in investing in the best equipment and negating the need to double spend in the future.
The ring flash has light output fixed right next to the front element of the lens. It acts as a blanket of light covering the whole object, creating a well lit, but flat image.
The twin flash acts as two distinct separate flash sources, creating an image with less light harshness, more depth, and emphasis of changes in line angle. You can also add flash modifiers such as bouncers or soft box to further enhance your images, creating a more artistic, softer image. The distance between the two light source can be altered when used in conjunction with specialised underbody bracket. This means you can mount the twin flash in a way for it to perform similar to a ring flash. However, these flash bracket can sometimes cost more than the flash itself. There are now affordable alternatives to these historically overpriced brackets. The FRC bracket is an affordable alternative for young dentists to be able to use a twin flash to maximise its potential.
* The twin flash has a much larger scope to perform better than the ring flash if used correctly. It can also be made easy to use if used alongside other equipment. If you plan on taking high-standard photos, don’t waste money on a ring flash and upgrade later on.
The Settings
The big 3
The 3 main camera settings are the ISO, the shutter speed, and the F-stop number (aperture). The ISO determines how sensitive the sensor is to light; the higher the sensitivity, the grainier the resulting image. The shutter speed controls the duration of exposure to light. Longer exposure time results in a brighter image,but it can cause motion blur if the camera is moved. The F-stop number controls the size of the aperture; the higher the number, the smaller the aperture, and the deeper the field of focus. Conversely, a lower F-stop number results in a shallower depth of field.
In dentistry, we aim for bright, sharp, and detailed intra-oral images with a wide depth of field. To achieve this, we need to use a low ISO, a fast shutter speed, and a high F- stop number (small aperture). These three settings result in a dark image, which can be overcome by using a powerful ring/twin flash to add more light to the scene.
The ideal intra-oral settings are as follows: ISO: 160
Shutter speed: 1/160
Aperture: F22
Flash: e-TTL*
To simplify your workflow when starting off, you can use a wider aperture of F8 for extra-oral photos.
It is recommended to always shoot with autofocus (AF) mode. In the past, cropping in on DSLR images produced pixelated results, but sensor technology has matured significantly in the past decade, making manual focus unnecessary for identifying specific magnifications.
*If you are using e-TTL and images are too dark due to different brands between flash and body, then you will need to set flash output as manual and control it yourself
The Recommended Setup
It really depends on your budget and priorities. If you want a just ‘to get the job done’ camera at the lowest possible cost, I recommend a Nikon setup of the following specifications:
Nikon D3500 body, Nikon 85mm F3.5 macro lens, Meike 14EXT ring flash.
This entry level set up will cost approximately £900 brand new. It produces a relatively flat image that is good for record-keeping, and it is one of the lightest setups available. However, it may not be ideal for patient communication and marketing.
For an additional £750 approximately, you can upgrade to a cost effective ideal set up with the following specifications:
Canon RP mirrorless, Meike RF-EF adapter, Sigma 105mm F2.8 macro lens, Yongnuo twin flash, FRC bracket, Neewer 6×5’ soft boxes x2
This full-frame mirrorless camera set up enhances your photography, creating artistic, harmonious photos. It goes beyond just clinical documentation and is great for showcasing, publication, and marketing.
The Level Up
There are 3 main subcategories of dental photography; intra-oral, extra-oral and lab work. These are all 3 completely different types of photography when you start to get better and more comfortable with taking photos. Intra-oral is more similar to macro photography, extra-oral is more similar to portrait photography, and lab work is more similar to product photography. As you get more comfortable and familiar with taking photos, you can consider investing in mobile backdrops, external speedlites, or a small lightbox to enhance your photography. These are not costly investments, yet they can greatly enhance your photography.
Dr Ferdi Chum BDS (Ncle) PgCert (ortho)
Co-Founder of Trinity Dental Courses
If you are interested in a great course for developing and enhancing your photography skills, visit www.trinitydentalcourses.co.uk
