To Flash or Not To Flash – That Is the Question

Posted in Photography Tricks, Under the Sea on October 19th, 2009 by MadDog
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Yes, you have guessed it. I am going to bore you once again with the topic, “Whether to Flash or Not?” This is a matter of little import to those who do not regularly submerge their precious cameras in high-pressure saltwater, something which surely violates fundamental laws of nature and sanity.

The vast majority of people snapping away today depend on their cameras to decide whether to flash or not. I am against this notion, since it produces countless nasty-looking photos Alas, I am a voice crying in the wilderness. My word on the matter is simple:  Learn how to make the flash on your camera submit to your will and then learn when you need it and when you’d get a getter image without it. Many people have thanked me for this entirely unsolicited advice. Your mileage may vary.

So, what’s the big deal underwater? Who cares?

Well, you do care, if you are interested in seeing what a given critter actually looks like underwater. If you just want a pretty picture with bright colours, then you turn on your flash and you will have far less work to do on your computer to get a usable, if misleading image. I usually want my images to display to you what I saw. Here is (yet another) example, a Divaricate Tree Coral (Dendronephthya roxasia):

Divaricate Tree Coral (Dendronephthya roxasia)

I think that it is quite pretty as it is. Moreover, it is exactly as it appeared to  me when I saw it at about 25 metres at Barracuda Point,  which is lousy with the things.

From the same position, I took this image with the flash turned on:

Divaricate Tree Coral (Dendronephthya roxasia)

Well, that too is a pretty image, but it’s not what I saw. One has to remember that, the deeper you go, the less of the spectrum is left. Only blue and a little greenish light penetrate more than a few metres. So, everything looks blue. Your eyes magically adjust to most of this and restore some balance. However, when you add the sunlight colours of the flash, which is designed to mimic sunlight (its colour temperature), then you completely upset the colours which are displayed in the resulting image. In effect, you have shown the object as it would appear at the surface.

Here’s another one:

Palm Coral (Clavularia sp.) - Available Light -

That’s a Palm Coral (some species of Clavularia)  which has appeared here before. It was shot in with the natural lighting. Check the delicate green shades in the centres, especially around the edges of the clump, where the exposure is a little less. This is a very pretty coral with delicate nuances of colour.

In this flash shot that I got last Saturday for comparison, the nuances are overpowered by the sunlight-white light of the flash:

Palm Coral (Clavularia sp.)

All of the pretty greens are lost.

Here is one more example. This one is a little harder to justify. This is our old friend and regular on Madang – Ples Bilong Mi,  the Spotted Shrimpgoby (Amblyeleotris guttata):

Spotted Shrimpgoby (Amblyeleotris guttata) - Available Light

For comparison, I made one exposure with natural light and one with flash. By now, I’m sure that you can see the difference. The shot above is flash-less.

This one is with the flash turned on. Again, it is not an unpleasing effect. In this case, it does score some points. Because it intensifies the colours that are the distinctive markings of the fish (primarily the orange spots and the dark pectoral fins, not to mention the clown-like eyes), it helps one to remember the primary identification features:

Spotted Shrimpgoby (Amblyeleotris guttata) - Flash

If you memorise the image above, you’ll have no trouble identifying the species when you are cruising over the sandy bottom.

You just have to remember that the first example image, without the flash, is how it is actually going to appear.

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