above image © Nick Blake

by Nicholas Watson

This basic guide is for you if you are: 

Starting out in Underwater Photography or want a few basic ideas about how to make your photographs better in a few easy steps.  It won’t replace face-to-face tuition, a more in-depth book, or workshop.  Remember Underwater Photography is potentially the most difficult genre of photography. Before you think about taking a camera underwater, you need to be a competent diver who has excellent buoyancy control. Your own personal safety, and that of the environment you’re working in should be your primary concern.  It’s a mistake to underestimate the task load that carrying a camera system entails.


In this guide you will be given some background to the basics, but if you are struggling, just follow the suggested settings and strobe positions.  This should help you get better results, and you will then want to tweak these as you grow in confidence.  These are the things that we will be discussing: 

The theory of exposure

  • Good photographs start with the correct exposure, meaning it isn’t over or under exposed for the strength of light (be it flash, ambient lighting or a combination of the two) in your image.  You can tell whether the image is exposed correctly by using the inbuilt light meter when looking through the viewfinder.  It’s in the viewfinder, but also on the LCD screen at the back as below.  Eventually you will review the exposure using the histogram of the image.   
  • Below are three examples of the LCD screen of a Nikon D90.  You will see the characteristic scale of overexposed (+) – correctly exposed (0) – underexposed (-).


Overexposed                                Correctly Exposed                           Underexposed

Figure 1: Overexposed (+)
Figure 2: Correctly Exposed (O)
Figure 3: Underexposed (-)

A correct exposure is determined by three variables, adjusted for differing light levels and creative purposes.  

    • ISO – sensitivity of the sensor e.g., ISO 320.  The higher the number the more sensitive the sensor is to light.  
    • Aperture – size of the hole that lets light onto the sensor e.g., f 13.  
      • A larger f number means a small hole, less light on the sensor and greater depth of field (sharpness). 
      • A smaller f number means a larger hole, more light on the sensor, and a shallower depth of field (portraits).
        • Depth of Field can be thought of in terms of the degree of sharpness across the image from the focus point.
          • From a very sharp depth of field across the image i.e., sharp front and back (high f, small hole) 
          • To a blurred foreground and/or background (also called bokeh) (small f, large hole)  
    • Shutter speed – how long the sensor is exposed to light for e.g., 1/125th sec.  
      • The larger the bottom number, the faster the shutter – freezes motion
      • The smaller the bottom number the slower the shutter – can allow blur

Photographers of all kinds change these three settings to gain the correct exposure, and for the creative effect they allow.

  • Changes to each of these are described in terms of ‘stops’.  For example 
    • Increase the ISO by one stop from ISO 320 to ISO 400
    • Open the aperture one stop from f13 to f11 
    • Slow the shutter speed one stop from 1/125th to 1/90th sec 
  • Look at your camera manual to set up your ‘stops’ consistently across ISO, aperture and shutter … or come to a BSoUP meeting!  
  • The Triangle of Exposure – the diagram on the right gives a visualisation of what happens when you make changes to the ISO, aperture and shutter speed.  But remember that this can’t be done in isolation to maintain the correct exposure e.g., closing the aperture will mean there is less light on the sensor, so you will need to compensate by slowing the shutter or increasing the ISO to maintain the correct exposure, or embrace the change for a creative ideal!  

What lens type to use

  • Macro or Wide Angle?  Macro is a term used to describe close up photography for smallish creatures, wide angle portrays bigger under scenes.  They both require different lenses, exposure settings, strobe positions, ideas around composition and approach.  With most set-ups it’s advisable to choose one or the other depending on what you are trying to shoot before entering the water.  

Suggested settings that work for better results

Camera settings:

Shoot on manual, and try these:


  • Macro ISO 200 / Aperture F8 / Shutter 1/250th Sec
  • Wide angle ISO 320 / Aperture F8 / Shutter 1/60th Sec


  • Macro ISO 320 / Aperture F16 / Shutter 1/200th Sec
  • Wide angle ISO 500 / Aperture F 11 / Shutter 1/60th Sec

Strobe power:

Using the above exposure settings, set the strobe power to manual:

  • Macro:  Start off with 2/3rds power
  • Wide Angle:  Start off with 1/3rds power   

Strobe positioning:

As a general rule whether shooting macro or wide angle:

Keep the strobes(s) aligned with the housing pointing straight forward. The nearer your port is to a subject the closer the strobe(s) need to be to the port.  The further away your subject is from the port, the further away the strobes need to be. 

Either way at this stage don’t push the strobe(s) forward of the port.

Figure 4: The closer you are to a subject, pull the strobes in, but still not forward of the dome port

Figure 5: The further away you are from a subject push the strobes out, but still not forward of the dome port


  • Macro – start by practicing on static objects, and check you are happy with the overall exposure.  Having tested the exposure, why not look for a small creature which doesn’t move too much at around the same distance?  Anemones are a good start, Crabs, Lobsters, Crayfish etc.  With the macro settings provided above you will get a black ground if the subject has nothing other than water behind it.  Think about shooting eye level – looking up, (not down).  Get close to your subject to try and fill the frame with its character.
Figure 6: Macro. A hungry Squat lobster in Scotland shot at eye level
Figure 7: Wide Angle using ambient light in the Red Sea (albeit from the side here but covered by the wreck)
Figure 8: Wide Angle - a Grey Seal in the Farnes using strobe lighting
  • Wide Angle – slightly more difficult to start off with, so start with no strobes and just get the ambient (natural) light right.  Remember to shoot with the sun behind you, not into it and use the table on P9 to adjust the exposure up or down.  Once you have the ambient light exposure right, bring in one or two strobes to light a subject in the foreground.   But most likely you will need to play with the strobe positions to get the correct effect, and it is likely that the strobe power will need to be lower on wide angle than macro.

Categories that seem to work well – quick wins: 

  • Eye level macro with a clean black background, shoot upwards.  
  • A pattern with no horizon or reference e.g., close up of a star fish or turtle back  
  • Wide angle scenes with a hint to the surface
  • Wrecks shot with ambient light 
  • Rule of thirds matching movement on the 3 x 3 gridlines
  • Diagonal movement in the frame 

In-water adjustment to suggested settings

When starting out (especially in UK waters), make life easy for yourself by shooting Macro with one strobe on top of the housing using the settings above. You can get some great results with this set up, and avoid the problems of having too much flash light in the image, with associated compositional issues when using two strobes.  

Start your experimentation by taking photographs of anything you want, but remember to practice getting closer than normal to the subject, shooting with an upwards feel.  Take time to control your breathing, compose the shot and press the shutter.  

When you think you are close get closer still!  

Review your LCD screen first, and look to see if it is over or under exposed (when you feel more confident you can check the histogram as the LCD screen doesn’t always give a completely accurate picture).  Using the table below, change one setting at a time, and try again.  Eventually experimenting with Wide Angle.

Changes to suggested settings above should LCD review suggest it's needed

Best practice

  • Shoot RAW (or equivalent for Compact Cameras) as there is more information to manipulate in processing
  • Charge your batteries at the end of each day
  • If you break a seal, clean it and lightly grease again
  • Back up your photos as soon as possible and store your hard drive in a different place to your laptop.

Post processing

  • Your RAW files will come out of the camera needing some adjustments to bring back what couldn’t be achieved underwater.  Adobe Lightroom works for most of what we do, and common tweaks are adjusting exposure, spot removal, dodging and burning, white balance and cropping are all common before exporting to your hard drive as a JPEG.
  • There are online courses available about how to use Lightroom better.
How I Edit Photos in Lightroom and Photoshop 2021 (Complete Tutorial) - YouTube

Further help

… including books and personal tuition can be found here: Learn (bsoup.org.uk)

And finally, from Alex Mustard ...

1 – Diving skills are the most important

2 – Get closer. All pictures should be taken within arm’s reach

3 – Use the right lenses

4 – Get the lighting right

5 – Dive with other photographers

Here are a selection of tips on Underwater Photography recommended by Dr Alex: