I saw some very cooperative and camera-friendly crabs at Bickley Bay, Rottnest Island. I just learnt that to get a close-up shot, you will have to get near but not too near. Hold on there for half a minute or so just watching them. Then you start shooting. You move your camera forward after every 10 seconds or so until you get the close-up shot you want. And the reward for your patience is that these guys will not run away. Of course I am talking about the cooperative ones, especially those in rock crevices. The ones sunbathing on the surface of rocks always fled before I could get reasonably near.