Hotshoe question

[kry10]

I am just wondering, what does a hotshoe actually do, just hold the flash, or, does it pass any signals to the flash in any way ?

 

[DazJW]

A coldshoe just holds the flash, a hotshoe has at least a firing signal though on modern cameras they pass other information too.

 

[mortimerhill]

The first hot shoes just had an electronic contact to fire the flash. As flashes and cameras became more sophisitcated, more info was passed between camera and flash. On Canon SLRs there is a main contact to fire the flash and four other contacts for the data transfer between camera and flash. With E-TTL the camera decides the flash duration and signals this to the flash. Other info passing between camera and flash will include flash ready signal, the lens's focal length and probably 101 other things.