One of the most common questions I hear from beginner underwater photographers is, “Do I really need to use a strobe?”. This is a very valid and important question. The addition of a strobe, or two strobes, adds a significant amount of bulk and weight to your camera setup. There’s also the fact that strobes are expensive. Taking these factors into account, it’s easy to see why this question should be carefully considered.
Like with many other all-important questions, the answer to this one is, “it depends”. It depends on several factors. Let’s go through a few of them.
Do you snorkel only? Or will you be scuba diving?
This is probably the most important factor to consider. In this discussion, it’s helpful to understand a bit about the color spectrum and how it is affected by water and depth. Water is a very effective absorber of light, and certain colors disappear quickly with each foot of depth or horizontal distance. Red is almost completely absorbed at 15 feet (5 meters). Orange and yellow are the next to disappear.
If you are snorkeling at shallow depths, you may be able to get good color in your photos using only natural light (sunlight). The time of day, your shooting angle and the weather conditions will be an important factor. Direct sun (or midday sun) coming from overhead often casts harsh shadows on your subject, so mid morning or afternoon sun is often best.
Whitetip Reef Shark, snorkeling photo, no flash. Notice the shadows on the subject due to shooting in mid-day sun.
Southern Stingray in St. John, snorkeling photo, no flash, shot in late afternoon. Notice the more diffused light.
What quality do you want in your photos? Think about the quality you want in your photographs. If you simply want a few snapshots to remember your adventures, and you are not looking for high quality, color-saturated images, you don’t necessarily need a strobe. Keep in mind that if you are diving below 10 feet (3 m), your photos will have a strong blue/green cast, and they will lack a variety of color tones. For some divers, this is perfectly acceptable. If, however, you want images that are suitable for framing or printing, you will want to use at least one strobe to restore the colors that are lost at depth. And please, shoot in RAW format if your camera allows (more on this here).
We recently photographed this longlure frogfish at 25 feet (8 m) with and without flash.
With flash (dual strobes), notice the color difference
What do you intend to photograph? Do you plan to photograph fish, humans, reefscapes, marine mammals, wrecks or something else entirely? This will be an important question to answer.
Let’s say you plan to shoot whale sharks while snorkeling. First, lucky you. Second, ambient light is probably best. Remember that your strobe will throw light about 5 feet (1.5 m) in distance. A whale shark is much, much larger than that. So it’s virtually impossible to evenly light an entire whale shark with one or two strobes.
Whale Shark in the Maldives, no flash
If you intend to photograph humpback whales, dolphins or marine mammals, sharks or large marine creatures in blue water, you should not use a strobe. Your strobe will not illuminate the entire subject, and swimming with it will limit your maneuverability while snorkeling. Try to position the sun to your back to help eliminate those pesky shadows (like you see in my whale shark photo above).
When your subjects are tropical fish, coral or reefscapes, you will need at least one strobe to bring out the full spectrum and saturation of colors that give the reef its beauty. Photographing a vibrant coral reef without a strobe isn’t likely to do it justice.
There are always exceptions to these general ideas about flash -vs- ambient light in underwater photography. We know one incredible reef/fish photographer who uses only the internal flash in the camera, and her results are unbelievable. We also know photographers who use LED lights for still photography underwater. Experienced photographers often develop their own unique techniques that fall outside of the norm. What are your thoughts on this? Do you use one strobe or two? Or just the sunlight?
More Reeftaveler posts about underwater photography techniques-
How to Take Better Fish Portraits
How to Take Your Snorkeling Photography to the Next Level
How to Take Better Fish Portraits
Underwater Photography Etiquette