Ring Flash Underwater Photography
One of the trickiest aspects of taking macro and super-macro images is providing even lighting to a tiny subject when it’s just inches away. Even relatively small strobes can be a tight fit when focusing on tiny critters. A ring flash, on the other hand, attached to the front of the lens, provides even lighting without having to maneuver your strobes.
What Is a Ring Flash?
The ring flash has its humble beginnings not in any form of underwater photography, or even topside shooting—rather to take pictures of teeth. Invented in 1953 by Lester Dine for dental photography, a ring flash is attached to the front of a lens, or for our purposes, the front of a macro port.
Today, there are countless ring flashes made for topside photography, but fewer for underwater purposes. Inon was the first to produce a ring flash for underwater use in 2001—the Z22 quad flash. Although this model has since been discontinued and is only available through resale, there are a couple other models available, including those produced by Athena and Saga.
Saga’s fiber-optic ring flash
The Athena ring flash works with the Sea & Sea line of strobes. Connected with an electronic sync cord, the ring flash fires its own flash using the power from the external strobe. The Saga ring flash, on the other hand, does not have a built-in flash tube, but rather redirects the strobe light using fiber-optic cables.
It is also possible to craft your own ring flash, much like a homemade snoot. Photographer Alex Mustard provides a good guide to making your own reflective-style ring flash.
Skeleton shrimp: f/22, 1/60s, ISO 160
Why Use a Ring Flash?
Ring flashes are best suited for super-macro, or subjects where the working distance makes it difficult to pull your external strobes in close enough for even lighting. The ring flash improves these images by producing more even lighting and softens highlights otherwise produced by awkwardly placed strobes.
There’s also a convenience factor for using the ring flash. On dives or trips when macro is your primary incentive, you can just leave the ring flash on to limit time wasted moving your strobe’s arms again and again, as is the case with traditional lighting. This leaves more time to focus on composition and creativity, and less time worrying about on strobe position.
While it is an extra financial investment and takes some time to learn, using a ring flash can actually be simpler to assemble and use than traditional strobes. With reflective-style or fiber-optic ring flashes, it’s also easy to remove the ring flash if you want to experiment with back- or side-lighting.
Boxer crab: f/32, 1/80s, ISO 250
Coral abstract: f/18, 1/80s, ISO 250
Assembling the Ring Flash
I have to admit that the first time I had a ring flash in my hands, I thought how difficult it would be to install and use. Although often considered an advanced technique, the assembly of a ring flash is actually quite simple.
In the case of a fiber-optic ring flash, like the one produced by Saga, the ring is attached to the very tip of the port, with a number of fiber-optic cables evenly spaced around the circumference. The ring either slides onto the port or screws on via a standard 67mm threaded port. The other end of the system can be easily mounted or unmounted from your external strobe, perfect for in-water use if you want to switch lighting methods.
For electronically connected ring flashes, the mounting process is virtually the same. However, these ring flashes are connected to the strobe electronically, so it’s impossible to remove completely underwater.
The Saga ring flash’s working range is between 2.5cm and 10cm from your subject
Spanish dancer and emperor shrimp: f/22, 1/60s, ISO 200
Using a Ring Flash
For those who love to take macro images and don’t want the hassle of constantly adjusting strobe position, a ring flash can be an indispensable tool. With the light provided in a circular pattern as close to the subject as possible, it allows the photographer to change between portrait and landscape composition without the need to constantly adjust strobe positioning.
Being lightweight and compact also allows the light to reach into cracks and holes that would otherwise be impossible with traditional strobes. This is especially important when working with shy subjects.
Harlequin shrimp: f/22, 1/80s, ISO 125
Whip coral goby: f/22, 1/125s, ISO 250
Ring Flash Settings
The settings for using a ring flash are, in many ways, similar to using a traditional strobe setup for macro. The only additional consideration is when using a fiber-optic ring flash. Some of the strobe output will be lost as it travels from the strobe to the device on the port through the fiber-optic cables. Thus, make sure to compensate either through a more open aperture or higher strobe output.
Starfish abstract: f/22, 1/125s, ISO 200
A ring flash is by no means a necessity for macro photography. The main effect you’ll notice from a ring flash is that, due to its even lighting and proximity to the subject, there will be limited shadows produced. In fact, some photographers prefer to have a little shadow in the image to add texture and depth.
The real benefit of using a ring flash is the ability to evenly light subjects in tight spaces or close proximity, when traditional strobes would prove cumbersome. Take, for example, this final image of a pygmy seahorse. In so many images of this subject, the polyps on the sea fan are closed because photographers accidentally bump it with their long strobe arms. With a ring flash, I was able to be more streamlined in my setup and capture the polyps and seahorse in picture-perfect condition.
Pygmy seahorse on sea fan: f/32, 1/90s, ISO 250