It’s all about the light – but just how much do you need underwater?

It’s all about the light … how many times have you heard that reply when you ask someone about taking underwater photographs?  What kind of light?  Light from above, light from the camera’s own ISO, aperture, shutter speed, from a torch, video light, flash light, someone’s else’s flashlight or maybe the camera’s own flash – or maybe none at all.

Light can be so confusing for a beginner when it comes to underwater photography.  It is so different from land where we just have the sun or daylight without it to deal with.  When we are underwater there are so many more options, and also not forgetting the deeper we go, the less of it we have to contend with, as well as losing the ability to see beautiful lush underwater colours.

From the first kind of Painted Frogfish ……… through to different kinds of the same Frogfish ….. They were all taken with a simple Canon Ixus on Programme Mode using the camera’s own flash.  Which one do you prefer?

So this is just a quick introduction to get you off the ground with understanding the basics, how it works and how to get up and running in a fast, easy-to-understand way to keep your colours vivid and punchy.  We will go through using external light sources very soon.

ISO, in an octopus shell, basically means light – how much light does the camera’s sensor need to keep the subject sharp, in focus and nice and colourful.  If there is insufficient light, you will end up with either a very dark subject, or a blurry one ….  Let in too much and it will be completely washed out and you won’t see your subject either.  Get it right and you’re smiling!  So how do you choose?

Well, firstly it all depends on your subject.  Is your subject still?  Is it near the surface as if so, there will already, hopefully, be some nice ambient light shining above you.  If so, a low ISO of 80/100 is ideal to keep your subject and its colours nicely crisp and therefore colourful.  This is the setting that the first picture of the Painted Frogfish was taken with.  As it was still and in about 5 metres of water in Egypt, where pretty much every day is a glorious shiny day, a low ISO was all I needed to use, particularly as I was using the camera’s built-in flash to light it up.  You can see that as I increased the ISO to 200 in the second picture and then to 400 in the third one, more light has crept into the image, leaving Little Miss Froggy looking mighty washed out.

However, if I had not been so shallow and instead of a flash I was using a red filter or the camera’s own custom white balance, I would maybe have to increase my ISO to maybe 200 to keep the picture sharp and in focus.  I say maybe, because the amount of light you will need to use to keep your image trip all depends firstly on where you are (if you are diving in cooler waters you will usually need a higher ISO to capture a decent image), secondly how deep you are, the deeper you go, the more light which is needed to keep your image sharp and thirdly, whether you are using an external light source such as a dive light, external strobe or maybe someone’s else torch.

It can all get rather confusing when starting out, so the best thing to do is if your overall image appears too bright to simply make sure that the ISO is lower and if your image is too dark, to simply increase it.

A fabulous way to get started is to focus on macro/close-up photography of subjects, set your camera on P mode, use the camera’s Macro Setting or Microscope setting on the Olympus TG4 model, a low ISO (if your subject is moving fast (i.e. dolphins) or  you are doing night dives, then a starting ISO of 200 is a better choice) and voila …. all fins crossed  you will have a nice, sharp, colourful subject.

Hope that this helps you to see the light a bit easier and am looking forward to sharing more tips with you soon 🙂






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