Advice requested please
 

I am using the SIGMA EF-530-ST Flash and want to start venturing into using Off camera flash. This flash is ETTL so can I buy a cable to achive off camera flash.

Hello lapcharlie, fistly, welcome to WPF. Secondly, yes, you can buy a cable to achieve off-camera use. You can either buy the cable sold by the manufacturer of your camera (Canon presumably as you said ETTL) and use the ETTL mode , or you can buy a very much cheaper "dumb" cable and a pair of adaptors with only a single contact for triggering, and use the manual settings on the camera and flashgun to achieve the results you want. The second option is much harder, takes lots of practice, but ultimately you'll learn more, oh, and it's a lot cheaper. Take a deep breath and have a chair handy before you look at the price of the dedicated ETTL cables.