Do you need a strobe?
One common question posed by newcomers to underwater photography is if strobes are required for capturing good underwater pictures. Strobes add more gear to your dive kit and of course add cost, so it is perhaps wishful thinking that they might be unnecessary. There are some circumstances where the benefit of strobes is less noticeable but there are certainly other circumstances where, without the use of a strobe, the results will be significantly diminished.
If you elect to forego adding a strobe to your camera gear, your other options for getting colorful photos are to use underwater modes, manually adjust white balance or use red filters. Snorkeling and shallow dives are good examples of when simply using underwater modes or adjusting white balance can work well. If you go a bit deeper you can use a red filter in conjunction with white balance adjustments to continue to get decent results. However, as your depth continues to increase these methods will eventually not be as helpful. Red filters work by limiting blue light, so if the only ambient light remaining is near the blue wavelength the filter will only make your photos darker. Without sufficient light reaching your camera sensor you simply won’t be able to get colorful photos.
It is also important to point out that adjusting white balance and adding filters only helps to retain color in your photos; these methods don’t improve contrast or sharpness. As long as you are using these strobe alternatives and shooting ambient, the quality of your results will still be limited by the amount of available light. Even if using these methods helps to retain some color, as you go deeper your images will suffer a loss of detail. Therefore, the deeper you go the more important a powerful light source will become.
Below are a series of photos taken with my TG-4 rig with and without my YS-03 strobe firing. I like to occasionally take back-to-back shots with and without my strobe to examine the difference after the dive. The first two shots are from diving Ulua Beach in Maui where the visibility was excellent and the average depth of the dive was only 20 feet. Both pictures were taken about 3-4 feet from the eel in the reef using my TG-4s underwater mode. While the picture on the left was taken without the strobe firing and still has some color and isn’t overly blue, its color isn’t as vivid and it isn’t as sharp as the foreground of the right photo, which was lit by my YS-03.
The next two photos were taken while diving a barge a few miles off the beach along the panhandle. Visibility was a modest 35 feet and the depth when the photo was taken was around 60 feet. In these shots my proximity to the subject was excellent at less than two feet, but it is still obvious which picture was taken with the strobe and which wasn’t based on color and overall quality. Great proximity helps, but even if you get very close as the ambient light levels drop-off your results will start declining.
The final two shots were taken while diving the bridge rubble a few miles south of Destin, Florida with only about 20 feet of visibility at a depth of 70 feet. Despite being within 2 feet of the scorpionfish when I took both photos, the lack of available ambient light demonstrates just how necessary a strobe is as your depth increases.
Light is extremely important for photography – without sufficient light, your camera simply will not be able to produce a usable image. And while the importance of light is mostly discussed in regard to color, it is highly important for good contrast and producing sharp images with excellent detail as well. As you go deeper, eventually ambient light won’t be enough to produce good underwater photographs. Once you decide to add a strobe and you begin becoming familiar with its use, you might find that even on shallow dives you prefer to bring it along because of the difference it can make.