OK, I have a question and google has not provided me with an answer I understand yet, so I thought I’d ask here in case someone knows.

When choosing a shutter speed I’m told to beware of the reciprocal length of the lens as anything slower than that may introduce shake in the finished picture. Thus a 50mm lens has the reciprocal of 1/50 and so the ideal shutter speed for a shot should ideally be more than that.

But, and here’s my question.

What about on a digital camera? I mean, I assume the rule applies to a standard full frame digital, but since my Canon 400D has a magnification factor of 1.6 (that is a 50mm lens on my camera is effectively the same as an 80mm lens on a 35mm – full frame – body), does that mean I actually need 1.6 stops faster?

So, does a 50mm lens on my camera needs 1/80sec?

OK, I know my mileage will vary and some people have remarkably steady hands (not me) but does this make sense?

If it does, it would explain away a lot of disappointing shots I’ve taken that I blamed on me being Mr Shaky Hands man.