pbelarge wrote in post #11739917
Thanks for the info.
I performed this function in live mode, and mode 2 definitely makes more of a difference, but it does not really silence the shutter, it slightly reduces the vibration.
Without live view, the mirror has to slap up and the mechanical shutter opens. After the exposure both shutter closes and the mirror returns so you can see again in the viewfinder. Higher frame rates and larger mirrors (ie full frame) means more mirror mass has to move faster, so there is more sound/vibration. With Live View in the 40D, S0D (presumably 60D), 7D, 5DII the mirror stays up the entire time, so mirror slap vibration & sound are altogether missing. In this regard Live View Silent shooting will always be significantly quieter than normal (viewfinder based) shooting as the mirror slap is the largest vibration in the exposure sequence. I saw a thread recently of a high speed video of an exposure showing this mirror slap and shutter action.
In all of these cameras the LV SS exposure is terminated with the mechanical shutter, which then reopens right away in Mode 1 or when you lift your finger off of the shutter button in mode 2. Thus the sound you hear is the shutter recocking and reopening after the exposure. Mode 2 simply spreads out the sound over a longer time making it less intrusive. Note that the shutter closing and reopening occur at the end of the exposure, thus its vibration contribution to the actual shot will be nil, whereas the mirror slap and shutter opening occur just before the exposure begins.