underwater Photo Course :: (2) Equipment Guide :: Underwater Camera Housings :: Digital Underwater Cameras :: Metering

It is an understatement that exposureRecording light onto photo sensitive devices and materials is something of an obsession for underwater photographers. Accurate exposure depends on accurate metering, which in turn depends on the quality of your camera. As a basic rule the more you spend the better your metering system is!

You will hear the acronym TTL a lot in underwater photography. It stands for Through The Lens. TTL gets used in a number of contexts, which can be confusing. TTL can be used for viewfinders that show you the image without any cropping. Its other main use is to describe the most common and accurate method of metering for exposure.

Although not foolproof, TTL metering yields the highest percentage of successful exposures in the majority of circumstances underwater. The current generation of cameras are even 'clever' enough to automatically handle the chore of balancing flash with ambient light. Nearly all underwater pictures are lit this way, which partly explains our obsession with exposure!

Digital cameras are at an advantage in that you can preview your image on your LCDLiquid Crystal Display. Such displays on the back of a digital camera allow you to preview images. These usually use TFT technology. Also used to display info on film cameras.. However, accurate first-time metering is still critical unless the shot can be retaken. And judging exposureRecording light onto photo sensitive devices and materials from LCD is tricky at the best of times. If you have the luxury, you can always look at the HistogramA graph of brightness along the horizontal axis (black to white) and the number of pixels at each brightness level on the vertical axis.. Later in our photo course you will learn how to interpret histograms and set up your Workflowthe process from taking your digital images downloading them onto a computer and color managing them through to printing and archiving them to optimize success.

Of course you can always go the route of a housingA casing or box with waterproof seals designed to contain a camera or other equipment in such a way that it can be used underwater. for a flash meter. If you have a medium format camera in a housing this is your only option but is regarded too cumbersome by other users.