The term “bokeh” comes from the Japanese word boke, which means “blur” or “haze”, and is the aesthetic quality of the blur, in the out-of-focus areas in an image. Originally Japanese photographers used this to create images with less-distracting, soft, pastel backgrounds, similar to some styles of Japanese painting.

This technique is particularly important with macro lenses, which photographers often deliberately use with a shallow depth-of-field (DOF), to give images with soft and smooth bokeh. This is useful when diving in bad visibility because it will completely blur the particles in the water column, and when shooting amongst the reef, it makes your subject stand out and the cluttered background becomes a piece of art. It is also an excellent technique to use on “boring” everyday subjects whilst your guide is busy hunting for the rare critters because it lets you experiment with colours and can show common subjects in a new way, framed by pastel shades.

Here are five tips to help you create nice bokeh in your underwater photos:

Tip No. 1: Use a low f-stop between f2.8 – f5.6 to give you a shallow DOF. Lenses with an f/2.8 aperture or faster, and dedicated macro lenses produce better and easier bokeh.

Tip No. 2: Shooting in Manual mode, with a low f-stop, you’ll likely need a faster shutter speed with a wide aperture, and you should keep your ISO to a minimum, and balance the light with your strobes, which probably need to be on their lowest power setting.

Tip No. 3: A shallow DOF is also dependent on the distance between the camera and the subject. The closer you are to your main focal point in the image, the more shallow your background will appear – which helps you to create nice bokeh. If you are extremely close to your subject, you may need to increase your f-stop to allow slight details in the background bokeh to be visible.

Tip No. 4: The distance between your subject and the background is also important for bokeh. The greater the distance, the more bokeh you'll get. Think about your background before you shoot: plain backgrounds such as blue water or fine sand are not ideal for creating nice bokeh images. Find a background with contrasts in colour and texture for a good result. In supermacro photography, often part of the subject itself is the background (eg. nudibranch).

Tip No. 5: Think about your composition and the “rule of thirds”, keeping your main subject (for example, the eye of a fish) off-centre. If you want to create a nice bokeh image, allow the viewer’s eyes to explore the rest of the image, rather than their eyes being drawn to the subject in the centre straight away.

Bokeh is an ideal effect to achieve for certain situations. Shooting portraits of marine animals is a good example. However, if you’re in a situation to capture interesting behaviour of an animal, trying to get “the shot” with a very low f-stop is not a good idea as you generally will want a much greater DOF.

Good bokeh can make your macro images look stunning, so follow these simple tips, and you’ll be well on your way to creating dreamy-looking images to wow your friends.

Christian Loader (29, UK) is a professional photographer for Scubazoo Images. He has worked extensively throughout Southeast Asia as an underwater videographer and photographer, and is currently based in Kota Kinabalu, Sabah, Malaysia.