Underwater Photography

Following his last article on working the subject, Martyn Guess provides some tips, information and advice for novice or new underwater photographers in order, to help them on their photographic journey

Photographs by Martyn Guess

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I have helped many budding photographers on their journey so my aim in the next few articles is to give some guidance and basic instruction to help you on your way. My view is that if you can get a few reasonable shots in the bag relatively quickly you will want to continue in your quest for knowledge. For many beginners, they have perhaps been diving for a while and now want to add another dimension to their enjoyment of the underwater world.

This was definitely the case for me. Some people decide to buy an underwater camera but have no knowledge at all about photography apart from using their phone perhaps, or a compact or bigger camera in fully automatic mode. Others perhaps with a bit of an advantage are keen abovewater photographers and have at least some photographic knowledge. Whatever your knowledge or type of camera that you have access to or own, be it a compact, mirrorless or DSLR, there are some basic first principles to take on board. My advice here applies to all types of cameras and knowledge base. The first thing to accept is that you are a diver first and a photographer second, so don’t let the latter get in the way of your safety and that of your buddy!

It is important to understand the controls of your camera and what the various buttons and menus do. If you don’t understand them on land, there is no hope when you get underwater. So, spend time reading the camera manual, researching online, and watching any tutorials for your camera that you can find. I am going to talk about basic

camera controls like Automatic or Programme Aperture Priority, ISO, Aperture and Speed and Manual M.

Unless you are content snapping close-up images of small critters in automatic mode and with the camera’s flash, and I mean very close, then the first lesson is to try and not be tempted to only use the automatic setting underwater. The camera’s electronics are designed for use on land, and it will struggle to take on board the complexity of lighting and deep shadows underwater, as well as the density of the particles suspended in our oceans. Some compact cameras have an underwater mode but, in my experience, they don’t work that well other than the foregoing very close-up critter shots. So, if you want to progress, please don’t use them. My preferred setting is Manual or M although as a learning

progression, Aperture Priority can work well. Manual means that you are taking full control and inputting settings for aperture and speed. Aperture Priority (AP) means that you are setting just the aperture and the camera the speed.

For those that don’t know, the aperture controls the lens diaphragm which controls the light getting through to the camera sensor. It also controls what is known as depth of fields (DOF), the amount of the picture in focus from foreground to background. A small aperture such as F22 and known perversely as a high F-stop will give you the biggest DOF, but the smallest amount of light getting through (image1). A larger aperture say F5.6 or low F-stop will reduce the amount of the background and also foreground in focus, which can be desirable for some arty macro shots (image 2) or to disguise the backgrounds in our images (image 3). It will also allow a lot more light though, which can be useful for very dark conditions in combination with ISO (More later). In AP, the camera will compensate for the amount of light getting through to the sensor by reducing or increasing the speed automatically. Slow to let more light in and the reverse for less light. If you can get your head round this, you are already on your journey!

For those who want to go straight to full manual Control M, then in addition to aperture, you are also able to control the shutter speed. This is the speed at which the camera’s curtain opens and shuts and thus controls the amount of time that the light hits the sensor. It is important in freezing the action with moving subjects and underwater helps to freeze the shot while we are swaying around in the current. (image 4). It is almost impossible to be as still underwater as we are on land! Speed can also help to control the background water colour underwater. A lower speed will give you a brighter colour be it green or blue water (image 5). A higher speed the converse. If you want a black background, for example, in a macro shot, then a high speed will assist (Find out what the highest speed your camera will sync with the internal flash or external strobes and don’t exceed this if using an artificial light source). In manual, the camera settings are used together harmoniously to create the best exposure, i.e. desired DOF, and the background lighting level and also to help freeze the action.

The next setting is ISO, which is the equivalent of film speed for old film cameras. You can adjust this whether in M or AP or fully automatic. ISO is how sensitive your camera is to light. Each ISO number be it higher or lower is a doubling or halving of the sensor’s sensitivity to light. Be aware that the higher the ISO, the more digital noise will be introduced, which degrades the image quality, so be aware of the optimum maximum ISO for your particular camera. More recent cameras can handle higher ISO settings very well and thus ISO is a very useful tool in getting the best exposure. Say you want to take a black background macro shot with lots of detail. Set a high Aperture, say F22 for maximum DOF, a high speed to darken the background. Take a shot and the image is too dark. Increase the ISO in combination with these settings to allow more light in and the image

becomes lighter. Its trial and error, but you will get a feel for the right settings.

I haven’t yet mentioned in any detail strobe lighting. Basically, we need to introduce artificial lighting underwater to bring back the vibrant colours we see underwater with our torches. Bear in mind that red disappears very quickly to our eyes, so at 5m we won’t pick red up. At 20m everything is mostly a green-blue. It is important therefore to introduce inbuilt or external flash/strobe lighting to make our images pop with colour. Don’t though assume that the flash will light up a very dark image on its own. My rule is to get the exposure right first and then introduce the strobe light to paint the picture with colour, whether this is just part of the foreground or a critter. Underwater flash photography is very different from land flash photography as the water column will reduce the effectiveness very quickly with distance. So going back to my macro settings of F22 and a high speed, introduce strobe lighting to pick out the subject in full colour and adjust the strobe intensity and ISO in combination to achieve the desired look that you are after in your image (image 6). All digital cameras have LCDs to review your images so you can easily review what you are taking and adjust accordingly. When you use strobe lighting though, please remember about the intensity of the light falling off very quickly, so the adage of ‘when you think you are close, get closer applies!’ We all think we are closer than we are underwater.

The closer you get to your subject, the less water column between the camera and the subject and the less suspended particles getting in the way of clearer images.

Generally speaking, beginners or novice underwater photographers will find Macro and close-up photography easier to start with. I strongly suggest that you start with this type of photography first. Practice on land with your camera with the various settings I have described and see if you can take a shot of a small ornament or flower with a black background (image7). When this is achieved easily then move onto more shots with open or low apertures to see if you can blur the background with an out-of-focus look, or bokeh, as it is described photographically. Don’t be frightened of adjusting aperture and speed in M or just the aperture in AP. Help lighten or darken the scene with small adjustments of ISO and then introduce some flash lighting. If you can achieve this on land, then you will be very well prepared for your next dive with a camera. Next time I will take you through some more basics to slowly build up your expertise and knowledge, but like everything in life, practice and practice to get better! n