Underwater Photography 101: “Azure Blue” Tips for achieving a beautiful blue background

Beautiful blue water behind a mesmerizing subject is one of the goals that every underwater photographer strives for.  It is not always easy, especially if the water you are diving in isn’t a beautiful blue!  This tutorial will address a few ways you can achieve great backgrounds in-camera, while giving your images a little creative punch.

Snake Pit small

Underwater photographers shooting with a DSLR or compact camera with a manual mode, have several options when it comes to capturing the color of the water behind a subject.  These options include the ISO, aperture, shutter speed, and strobe use.  I always shoot in manual mode when I am under water.  It allows me to control how much light reaches my sensor.

In the photograph below, I used a higher ISO to boost the ambient light in the image.  In this case, I had the ISO set to 500.  This allowed more color and light saturation.  Historically, DSLR’s have a lot of “noise” when the ISO is higher.  However, the newer cameras are capable of getting a finer image with a higher ISO.  This can be a great advantage to the underwater photographer.


Aperture is one of the tricky concepts when trying to control ambient light and get a bright blue background. Opening up the aperture does allow more light and may be necessary if you are using a high shutter speed. If for example, you are trying to freeze the sunbeams coming down through the water, you would want a high shutter speed to stop the light (1/250th or higher) and meter the background for aperture, so the sun isn’t too bright. This image has a shutter speed of 1/320th (the highest speed my strobes can sync with). The aperture is f/11.

A Hard and a soft coral bask in the sun

A Hard and a soft coral bask in the sun

If you are using strobes, (and sunbeams aren’t a factor) I advise using an aperture of f/8 or above, and metering into the blue water for the shutter speed.  The ISO may need to be a bit higher as well. The strobes fire at a fraction of the shutter speed and will freeze the subject so you can use shutter speeds as low as 1/13th, 1/25th, or 1/30th for close focus, wide angle shots, and macro shots.  The image below has an ISO of 200, high aperture at f/18, and very slow shutter speed at 1/13th.  The strobes fire at about 1/1000th of a second, so the movement of the subject is frozen because it is only lit up for a fraction of the time the shutter is open.


Macro shots can be very interesting when they utilize ambient light.  This tiny nudibranch was created using a higher ISO (400) and shooting almost directly into the sun to get enough light to expose the blue background.  Because I wanted a sharp focus on the entire nudibranch, I stopped down the aperture to f/36, and the shutter speed was metered against the sun to 1/80th.

Placida cremoniana

Placida cremoniana

It has been very trendy lately to get a black background behind your subject.  To achieve this, you need to have nothing but water behind your subject, and a high shutter speed.  Here is the same nudibranch with drastically different settings:  ISO 100, f/36, 1/320th.  This lets in no ambient light.  Only the strobe lights the subject.  Which image do you like better?


If you are new to underwater photography, you should spend some time experimenting with the aperture, shutter speed and ISO settings on your camera.  Light plays such a big part in creating images, that it is arguably the most important concept to master as a photographer.

If you have questions, or suggestions for underwater photography tips, please feel free to leave comments below.

As always, if you enjoy my images please visit my website, waterdogphotography.com, or give me a like on facebook at Waterdog Photography Brook Peterson.  Don’t forget to follow me here atwaterdogphotographyblog!
My photographs are taken with a Nikon D7000 in Sea and Sea Housing using two YS-D1 Strobes.
All images are copyrighted by Brook Peterson and may only be used with written permission.  Please do not copy or print them.  To discuss terms for using these images, please contact me




New Gallery!

This is just a quick post to announce that I have updated my California Gallery to include recent photo contest winners, and new images taken in the California coast.  Please click on one of the the links (or any of the images below) and have a look!

Waterdog Photography Galleries/Home


Waterdog Photography Galleries/Southern California  (NEW!)

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Waterdog Photography Galleries/Indo-Pacific


Waterdog Photography Galleries/The Great Barrier Reef

Snake Pit small

Waterdog Photography Galleries/Hawaii

Vinny Ray (a young male Manta) and two friends

Vinny Ray (a young male Manta) and two friends

Waterdog Photography Galleries/Home

Charmed, I’m Sure

When people find out I am a scuba diver, the first question most of them ask is, “Aren’t you afraid?”  I can honestly answer that, No, I am not afraid.  In fact, any fear that I should have is immediately pushed aside in favor of fascination when I am under the water.  I believe that this is the innate nature of the sport, and that most divers will claim that fascination overcomes fear.  Some of the creatures that might inspire fear are great photo subjects.  Others appear harmless, but may pack a punch if their environment is disturbed too much.

Snake Pit small

This sea snake, and several others like it, kept several of the divers on the boat.  That was unfortunate for them, because I had a fabulous interaction with the snakes.  They followed me around the dive site, curiously posing for the camera and watching their reflections in my dome port.  I didn’t know it at the time, but two of the snakes entangled themselves in my legs as I was leaving the site, and my husband captured it on his GoPro.  I enjoyed this dive more than any other because of the snakes, and never even considered fear among my reactions to them.

Eels breath by forcing water through their gills through their mouths.  That's why their mouths are often open.

Eels breath by forcing water through their gills through their mouths. That’s why their mouths are often open.

Another creature that inspires fear is the eel.  They do have a lot of teeth, and their mouths are often open which may make them look formidable.  Most of the time, though, they are simply breathing or being cleaned by the shrimp that inhabit their dens with them.

Mooray eel

This barracuda might have been a little upset at my presence in the water.  At the time, I thought he was just very interested in having his picture taken as he kept circling me, coming closer each time.  This is one creature I should have had more respect for, as he is capable of harm if he feels threatened.  However, fear never crossed my mind, and it was only with hindsight that I realized his aggressive behavior was a warning.


This small fireworm looks harmless enough.  It is important that you never assume anything, though and never touch a creature even if it appears harmless.  The fibers on the sides of the worm have a stinging venom that can be quite uncomfortable.


Here’s another venomous fish, that is absolutely beautiful, but has stinging fins.  This one was guarding it’s many children which can be seen along the right side of the photograph.


Sometimes fish just look formidable.  Or just plain ugly, like this toad fish.


This Cabezon aggressively attacked my camera.  He was less than a foot long, and didn’t have teeth, but he had an impressive nest to guard, and perceived me as a threat.  I still didn’t fear him, but I did respect his space, and backed off when I realized I had stressed him.

cabezon with eggs

So to my non-diving friends; the creatures in the ocean don’t need to be feared, but they do need to be respected.  The likelihood of being a victim of an attack is very small when you respect the reef and it’s inhabitants.  A little education about sea life goes a long way too!  Most of the time, I am simply charmed.