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Underwater Photography Essentials: Part 3



Underwater Photography

Tips, ideas and advice for budding underwater photographers

by Nick Robertson-Brown FRPS

Part 3: Getting to grips with your camera settings – ISO

Read Part 1 of Underwater Photography Essentials here.

Read Part 2 here.

Underwater Photography

The third element in controlling the exposure value is the ISO. The term ISO is an acronym for the International Standards Organisation which prescribed a common standard for the sensitivity of a film many years ago. The higher the ISO number, the greater the sensitivity to light; but it came at a price. As the sensitivity to light improves and the ISO number on the film gets higher, the lower the quality of the image becomes. With a high ISO film, the image looks grainy and hence the resolution is reduced. The same standard has been maintained in digital imagery, whereby the exposure value of a digital image will be the same as it is on a film camera, as long as all the settings are the same. There are, however, still penalties as you increase the ISO value. In much the same way as it did on film cameras, the image becomes grainy, but we refer to this as noise – and a noisy image has very restricted uses.

Underwater Photography

On the face of it, it would appear that increasing the ISO is a great way to increase the exposure value of your image with no major side-effects. Only a few years ago, using the ISO as part of the exposure triangle was restricted to changes between ISO 100 and ISO 800 (at best). Modern technology has come a long way in the last 4 to 5 years and on some cameras, mostly expensive ones, ISO values of 2500 can produce images with very little noise.

With the introduction of modern technology, the ISO setting is now a serious tool to be exploited underwater, as high ISOs are ideal for working in low light conditions. The ability of an individual camera at different ISOs will vary between manufacturers and camera models and it is important that you understand the limitations of your own camera so you know how far you can push the limits of the ISO setting. You can test this limit by taking a sequence of images into shadow and increasing the ISO on each shot. The low ISO image should look clean and black, whereas the high ISO image will look really noisy with hundreds of tiny red or blue dots which become clearly apparent when you zoom in. By taking a sequence of images, you can look at the effect as you increase the ISO, and you can decide how high an ISO value you are happy with. There is a certain amount of subjectivity in this, but it is what you think that is important.

Having the ISO set to the right value is still important, despite the advances in technology. Ideally, the default setting should be at your lowest ISO setting, which is usually 100 and this means your images will give the best resolution of your camera can produce. Whilst an image which you have taken at ISO 400 for example, may look as good as the one you took at 100, when you zoom in, and look really closely at it, you will appreciate the higher resolution of ISO 100.

One point I should make about using the ISO at high values, is that on certain images, the noise can actually work, possibly even enhancing the result. However, this is unusual, and increasing the ISO level should really only be used if reducing the shutter speed would induce motion blur or shake, and opening the f-stop would reduce your depth of field beyond the level you are comfortable with.

Underwater Photography

This image of the wreck of the Giannis D is shot with a high ISO (1250) on a Nikon D800, so whilst there is some noise, it suits a wreck shot.

Now that we have discussed all three factors that affect exposure control, pick up your camera, put it into manual, and start to experiment.

Whilst we are dedicated Nikon camera users, we found this useful tool on the Canon website and thought it was worth posting. You do not even need to get your camera out to see how ISO, Aperture and Shutter Speed interact – as you can give it a go on this handy web tool whilst sat at your computer:


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


Ocean Art 2020 Winners Announced!



Ocean Art Contest Announces the Best Underwater Photos of the Year

The prestigious Ocean Art Underwater Photo Competition, organized by the Underwater Photography Guide, has announced the best underwater photos this year with its 2020 winners. Despite global travel restrictions and the challenges brought by the Covid-19 pandemic, the 9th annual competition attracted an extremely high caliber of photos from oceans around the world. Underwater explorers captured photos locally, in select destinations currently open to travel, or revisited their archives to bring us some eye-catching photography. This unique assortment of photos could not have been possible without the help of our generous sponsors who have all had to navigate a changing travel and dive industry. Many of these same sponsors helped the Ocean Art competition raise money earlier in this year to raise money to donate to the WHO and CDC in their fight against Covid-19. These photos showcase the perseverance of underwater artistry amidst the adversity of the times.

All the winning photos can be seen at the Underwater Photography Guide at

The Best of Show is a once-in-a-lifetime moment of an octopus taking a selfie with the photographer and his curious family in the background. The photo was captured by photographer Gaetano Dario Gargiulo close to his home in the tide pools of Kamay Botany Bay National Park, New South Wales, Australia.  Other extraordinary winners include astonishing scenes of animal behavior, images that bring hope for the next generation of sea creatures, displays of ingenious photographic technique, and conservation scenes that reflect on not just the need to conserve our planet, but our species as well. The judges evaluated thousands of entries from 80 countries before selecting the final set of images as Ocean Art winners.

Ocean Art 2020 judges included prestigious underwater photographers Tony Wu, Mark Strickland, and Marty Snyderman.

Over $45,000 in prizes have be awarded, making the Ocean Art prize value among the highest in the world.

Ocean Art prizes are provided by some of the world’s top scuba diving resorts, liveaboard dive yachts, and underwater photo gear manufacturers. Grand prizes include a choice of 7 or 8 nights for two aboard the Coralia Liveaboard in Raja Ampat or Komodo, a 7 night liveaboard trip on the M.V. Bilikili in the Solomon Islands, a 7-night dive package with Villa Markisa, a 7 night dive package at Siladen Resort & Spa in Bunaken, a 12 night Passport to Paradise with Murex Dive Resorts and Lembeh Resort to three different Indonesian destinations, a 5-night dive vacation with AquaMarine Diving Bali & Ramayana Candidasa, a 7-night dive vacation at Atlantis Philippines Dive Resorts, and a variety of gift certificates from Bluewater Photo and Bluewater Travel. Premium travel prizes are provided by Volivoli Beach Resort (Fiji), Crystal Blue Dive Resort (Philippines), and Solitude Liveaboards & Resorts (Philippines and Indonesia). Premium gear prizes are provided by Sea & Sea and Ikelite. 12 different categories ensure a competitive contest for all levels and disciplines of underwater photography.

The photographic ingenuity from competitors is getting better every year – making judging very difficult and demonstrating that the winning images are some of the best in the world. Bluewater Photo and Bluewater Travel owner and Underwater Photography Guide publisher, Scott Gietler commented, “The Ocean Art team was thrilled to see that so many photographers were able to get out, dive, and immerse themselves in photography this year. The Best of Show was especially impressive. My only concern is that the octopus should get its share of the prize, as it did assist in taking the shot!” 

For more information, please visit 

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Gear Reviews

Gear Review: SeaLife SportDiver housing for iPhone (Watch Video)



In a video shot exclusively for, Jeff Goodman reviews the SeaLife SportDiver housing for Apple’s iPhone, used with the Sea Dragon 2500 Light.

For more information about Sealife Underwater Cameras visit the website by clicking here

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Call Diverse Travel on 01473 852002 or email to book your spot!

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