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Underwater Photography Essentials: Part 1



underwater photography

Tips, ideas and advice for budding underwater photographers

by Nick Robertson-Brown FRPS

Part 1: Getting to grips with your camera settings – Aperture

When you look at your subject underwater, without using artificial light, there are essentially three factors that you can change on your camera to create the image you want. These three factors are aperture, shutter speed and ISO and all three have an effect upon how the image will look. Each will have their own individual characteristic upon the outcome of your image, and usually, by changing one of these factors, one of the others will need to be adjusted to compensate for what you have done. In order to maintain the same amount of light in your image, the exposure value (EV), increasing the light from one of these factors will mean you need to decrease the light using one of the other two.

underwater photography

It is a case of balancing the light to get the right value for the image you want to create. How you balance this value will give you, the photographer, control of how you wish the image to look. In this first article, we are going to look at Aperture.


The aperture is the space behind the lens through which the light enters the camera, and hence, the sensor. The aperture works very much in the same way as the pupil of the human eye. In bright light, the pupil will close down to a small round opening, hence restricting the amount of light that falls on the retina. As it gets darker, the pupil dilates to allow more light to enter the eye. The aperture of the camera’s lens can be opened and closed, just like the pupil of the eye, and if you have your camera in the auto setting, this is one factor the camera may use to change the exposure value. This is why I think it is important that you should use the manual setting so you have control of how you want to present your image.

Aperture Setting

The aperture setting is referred to as the f-stop or f-number, and the smaller the number, the larger the aperture. Mechanically, the size of the hole is determined by a circle of blades that cause the central aperture to open and close by the overlapping of these blades on each other. Closing the aperture will restrict the amount of light hitting the sensor and the f-number increases. This f-number is not just a random figure, but is in fact a ratio of the focal length of the lens to the physical size of the aperture. In most compact cameras there is no mechanical closing of an aperture but its attributes are produced electronically to give the same effect.

underwater photography

The figure above shows the f-value and all camera lenses are calibrated using the same f-stop scale. The range of aperture numbers does vary from one lens to another, with the greater range generally equating to the greater price. The scale, however, is always constant and each increase in f-stop number equates to half the amount of light that is allowed through to the sensor.

Depth of Field

Opening and closing the aperture, or decreasing and increasing the f-stop, would appear to be a simple way of changing the light level on the sensor. As the aperture is opened however, the depth of field is reduced, and this has a very noticeable effect upon the image. The depth of field is defined as the amount of the image which appears to be acceptably in focus, and changing the depth of field on your subject can create very different images.

underwater photography

As you can see from the above image, the pygmy seahorse is in sharp focus. The rest of the coral behind it is totally out of focus, and this has the effect of making the seahorse, your subject, pop out from the picture.

And again with this ghost pipefish, the subject is in focus, but the background is blurry and there can be no misunderstanding as to what the subject is.

underwater photography

This does not necessarily mean that you should always use a small depth of field to make your subject pop out, and there are times when the environment around the subject is important. This technique is used by many underwater photographers as it allows you to virtually eliminate any messy background by using a low f-stop number to create a small depth of field. This is ideal for when your subject will not come out into the open. The blurry background in an image is called “Bokeh”

Of course, sometimes you want to show the critter in its environment and to do this, you need to increase the f-stop (close down the aperture). As a result of closing down the aperture, the exposure value will go down as you are letting less light onto the sensor. Within the exposure triangle, there are two other factors you can adjust and I will be looking at these controls next time.


underwater photography

Do you want to learn more? You can pick up a copy of Nick’s book “Underwater Photography Art & Techniques” by clicking here.

Underwater Photography Courses

Contact Nick for information on the Frogfish Photography Complete Underwater Photography Award, designed for 1:1 and small group sessions to improve your underwater photography at your pace.underwater photography

           |  | +44 (0)161 9177101

Nick and Caroline (Frogfish Photography) are a married couple of conservation driven underwater photo-journalists and authors. Both have honours degrees from Manchester University, in Environmental Biology and Biology respectively, with Nick being a Fellow of the Royal Photographic Society, a former high school science teacher with a DipEd in Teaching Studies. Caroline has an MSc in Animal Behaviour specializing in Caribbean Ecology. They are multiple award-winning photographers and along with 4 published books, feature regularly in the diving, wildlife and international press They are the Underwater Photography and Deputy Editors at Scubaverse and Dive Travel Adventures. Winners of the Caribbean Tourism Organization Photo-journalist of the Year for a feature on Shark Diving in The Bahamas, and they have been placed in every year they have entered. Nick and Caroline regularly use their free time to visit schools, both in the UK and on their travels, to discuss the important issues of marine conservation, sharks and plastic pollution. They are ambassadors for Sharks4Kids and founders of SeaStraw. They are Dive Ambassadors for The Islands of The Bahamas and are supported by Mares, Paralenz, Nauticam and Olympus. To find out more visit


Nauticam announce NA-A7C Housing for Sony a7C Camera



Sony’s latest full frame mirrorless camera, the a7C offers the underwater image maker one of the most compact and travel friendly full frame systems available on the market today.  The a7C features Sony’s latest stellar autofocus and a much improved battery life thanks to its use of the larger Z series battery. The BIONZ X processor delivers superb low-light performance and faster image processing. For video shooters, the a7C features internal UHD 4K capture in the wide-dynamic range HLG image profile at up to 30p.

Nauticam has housed more mirrorless cameras, and more Sony E Mount cameras than any other housing manufacturer. This experience results in the most evolved housing line with broadest range of accessories available today.

Pioneering optical accessories elevate performance to a new level. Magnifying viewfinders, the sharpest super macro accessory lenses ever made, and now the highest quality water contact wide angle lenses (the WWL-1B and WACP-1) combine with the NA-A7C housing to form a complete imaging system.

Nauticam is known for ergonomics, and an unmatched experience. Key controls are placed at the photographer’s fingertips. The housing and accessories are light weight, and easy to assemble. The camera drops in without any control presetting, and lens port changes are effortless.

NA-A7C features an integrated handle system. This ergonomic style provides exceptional control access, even with thick gloves, with ideal placement of the shutter release and a thumb-lever to actuate the AF-ON button from the right handle.

Nauticam build quality is well known by underwater photographers around the globe. The housing is machined from a solid block of aluminum, then hard anodized making it impervious to salt water corrosion. Marine grade stainless and plastic parts complete the housing, and it is backed by a two year warranty against manufacturing defects.

For more information in the UK visit the Nauticam website by clicking here.

For more information in the USA visit the Nauticam website by clicking here.

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INON announce SD Front Mask and M67 filter adapters for GoPro Hero 8 and Hero 9



The new SD Front Mask enables users to enjoy dedicated the semi-fisheye lens (the UFL-G140SD) which increases the underwater angle of view and minimises shooting distance.  It also enables users to attach the dedicated wide close-up lens (the UCL-G165SD) which provides ideal coverage and shooting distance for taking video of marine life.

The M67 Filter Adapters allow underwater videographers to attach the INON UW Variable Red Filter to easily obtain natural colour without a blue/green colour cast. To learn more about these filters watch the video below.

No need to bring couple of filters underwater and swap them depending on depth. It is easy to adjust colour tone simply by turning the filter edge and stop turning when you see appropriate white balance on your screen.

For more information visit the INON UK website by clicking here.

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