For a start, they never stop moving. Worse still, if you’re pursuing them in a RIB, neither do you. Then there’s the problem of reflected light, both from white shiny plastic surfaces and the sea itself. Having watched the way some of the best professionals go about it, I’m constantly impressed by their humility. I remember Alastair Black telling me how he always ‘bracketed’ his exposures with a range of different settings because, with so many variables, you never really knew in advance which one would work out best. I found that hugely reassuring. Another veteran ‘hot shot’ conceded that the most amazing pictures he’d ever taken were the ones that emerged, incomplete, on the perforated section of film at the end of the roll. That, of course, was before digital photography – something that Patrick Roach embraced with enthusiasm long before most of his peers.

This forward-looking approach is evident in this graphic guide, which demonstrates his truly expert grasp of current technology. In that respect, because Patrick is so comfortable with the medium, he makes it all sound, if not simple, then certainly seductive. Cleverly, he leads us in gently, saving the more detailed stuff, such as fill-in flash, custom settings, aspect ratios, toning and printing, for later chapters, by which time he hopes we’ll feel sufficiently confident to absorb it. However, this book is rooted in practice rather than theory, for while the author constantly encourages us to read and re-read the relevant instruction manuals, it’s through the numerous pictures on display that he tries to explain precisely what’s going on. He also bangs the drum for progress and innovation, insisting that modern zoom lenses are every bit as good as their fixed equivalents and that IS or image stabilisation has completely revolutionised the use of larger lenses at sea.