Macro Underwater Photography with Motion Blur
A static lizardfish provides the perfect subject for the macro motion blur technique
Motion blur photography is a technique used to create the impression of movement in a still image by using slow shutter speeds and strobe lights to freeze part of the action and blur the rest.
On the other hand, macro underwater photography usually requires strobe lighting in combination with fast shutter speeds to completely reduce ambient light and capture every detail in the frame. But why not experiment with motion blur techniques on smaller subjects such as frogfish, octopuses and seahorses?
A goby on a whip coral shot at f/20 with a shutter speed of 1/5s. A strobe lights the entire frame, while a torch is used on the lower part of the body
Equipment and Settings
To achieve the types of images featured in this article, two sources of light are needed, strobe light and continuous light such as from a dive torch, both with snoots attached. The snoots are necessary to precisely light the parts of the image you wish to highlight. Of course, you will also need a macro lens suitable for the subject you are planning to shoot.
As most underwater photographers should already understand, whenever you press the shutter, a fiber-optic or electronic cable that connects to your strobes signals them to fire instantly. Because the camera is set to front curtain sync, this will freeze the strobe lit part of the image instantaneously, keeping these details sharp and in focus. Immediately after pressing the shutter, you quickly move the camera from left to right, or vice versa, and this fraction of a second of movement combined with the torch light is what creates the blurred part of the image.
On paper, it sounds more complicated than it is in practice, but I will repeat this part again as it is critical to the success of this technique: During panning of the camera, the continuous light must always remain in the exact same position while the camera moves quickly using a slow shutter speed to create the desired effect. The settings I discovered work best are a shutter speed between a quarter and an eighth of a second, and an aperture of between f/16 and f/22.
An emperor angelfish shot at f/18 with a shutter speed of 1/5s. The face is lit with a strobe, and a torch lights the tail while panning right
Setting Up the Shot
Now for the bad news. One cannot produce these kinds of images alone, as it is practically impossible to hold the torch in a steady position while also panning the camera. Qualified help is needed to hold the snooted torch in place.
Every single one of the images in this article was taken in Tulamben, Bali, Indonesia with the help of my talented dive guide Ajiex Dharma. Ajiex is a master of snoot photography, so he knew exactly where to aim the torch and the strobe light while I concentrated on composition and panning the camera. It was truly a team effort, and by enlisting the help of someone who understood the technique and also knew where to find some awesome critters, we were able to produce this entire collection in around 25 dives with no previous experience in motion blur techniques whatsoever.
Same settings, different results, depending on where you aim the strobe and torch
All of the above images of this thorny seahorse were taken using the exact same settings (f/18, 1/6s), but you can see each image has a different final effect. The difference between each shot is the strobe and torch position, and the speed of camera panning. What these photographs clearly demonstrate is that the result is largely dictated by light positioning, which is what makes this very much a technique that’s all about experimenting—and having fun doing it!
As the photographer, you have to get creative and decide what final effect you would like to produce. Your options can be divided into the following categories: (i) blurring the subject, (ii) blurring the background, and (iii) a combination of both.
A lionfish shot at f/20, 1/5s. The body is lit with a strobe, and the tail is lit with a torch while panning to the right
Blurring the Subject
If you plan to blur the subject itself, it is important to remember that the viewer still needs to easily identify whatever it is you are shooting, and that certain rules still apply. The eye and face of the subject must always be sharp, so aim the strobe light to ensure you freeze this part of the image. It normally works best to blur the lower half of the body or the tail of the subject, so aim the torch at this part of the frame—and keep it pointed there as you move the camera.
It is important that excess light does not blow out the image entirely when shooting at such slow shutter speeds, so keep the ISO as low as possible, use a high f-stop as already mentioned, and try to shoot late in the day or at night to reduce the ambient light as much as possible.
Fish are the first choice for this technique, as the feeling of motion is more natural, so avoid shooting static subjects in this way, unless of course you are deliberately trying to create surreal images. The images featured up to this point, and below, provide good examples of successfully adding motion blur to the subject.
A frogfish shot at f/18, 1/8s. Again, strobe to the body and torch to the tail while panning right
A frogfish yawn shot at f/22, 1/8s. Once again, strobe to the face, torch to the rear while panning right
Blurring the Background
The second option you have is to keep the subject completely sharp while purposefully blurring the background behind it. To do this, aim the snooted strobe so that it completely lights the entire subject to freeze it as you would do in a standard macro photography shot, and then aim the continuous light at the background while panning the camera. The difference between lighting the entire subject or just a part of it may be a small adjustment in the strobe position, but this will have a big effect on your final image.
The best subjects for blurry backgrounds are normally static creatures such as crabs, frogfish and nudibranchs. Below are some examples of this technique in action.
A harlequin crab shot at f/22, 1/4s. Here, the crab and anemone are lit with a strobe, while a torch illuminates the anemone, panning downwards
A filefish shot at f/18, 1/5s. Strobe to the fish, torch to the crinoid, panning left
A filefish hidden in a sea urchin shot at f/22, 1/6s. Strobe to the fish, torch to sea urchin, panning downwards
Sometimes, it simply works best to blur most of the frame, and the best way to do this is to once again use the strobe to freeze the eye(s) and face of the subject, and use a combination of the torch light and ambient light to blur the rest. This type of image works best when you have a fish or other active subject moving in their natural habitat. You can see examples of this effect below.
A ribbon eel shot at f/18, 1/8s. This time, strobe and torch to the eel, ambient light for the background, panning right
A filefish in sea urchin shot at f/22, 1/6s. Here, strobe to the face, and torch to upper body and background
A mimic octopus shot at f/18, 1/6s. This time, strobe to the body, torch to the arms, and ambient light for the background
Like any creative photography technique, it is perfectly acceptable to break the rules and experiment. Sometimes, the result is not exactly what you hoped for, but these “mistakes” often result in abstract shots that are still interesting and pleasing. For instance, the following images of a Rhinopias and a frogfish feature much more blur than originally intended, but I still like the results!
Rhinopias shot at f/18, 1/6s
A frogfish shot at f/18, 1/6s
As the technique requires two narrow beams of light and some coordination between two divers, it is hardly surprising that it doesn’t always go to plan. To help explain how things can go wrong, here are a few images that demonstrate some common mistakes.
Here, the eyes should be sharp without motion blur
In this image, you can see the continuous light (the torch) was aimed incorrectly—at the eye and face of the crab—resulting in trails of motion blur instead of a sharp face lit by a strobe as intended.
In this image, insufficient space was allowed at the edge of the frame and the motion blur effect was cut off
Remember that you will be panning the camera in one direction, so make sure to leave enough space in the frame for the motion blur effect. In the above shot, the blur behind the seahorse—while not a complete disaster—is not ideal either.
The transition between the two light sources is too harsh
If your strobe light and torch light do not meet and mix correctly, you will end up with a rough transition between the in-focus part of the shot and the blurred part.
Whatever the results, experimenting with new tools and ideas underwater is a fantastic way to create unique images that can help to separate your portfolio from the rest. The next time you visit a productive dive destination and feel like trying something different, consider enlisting the help of another photographer or dive guide and attempting some macro motion blur.