Originally posted by Judd For a digital (not full-size format), is it reasonable to assume that one would need to also use the reciprocal of the crop factor as a multiplier if using an older film lens (for instance, if using an older 50mm film lens on a dSLR, the minimum shutter speed would be 1/50 x 1/1.5 = 1/75 sec)?
Yes, to the extent that even the 1/50" was anything more than a rough approximation of a speed that was "likely" to give a person of "average" steadiness "acceptable" results "most" of the time, on prints of a "typical" size viewed at a "comfortable" viewing distance. Did I put enough quotes in there to suggest that this number is really just a rough rule of thumb?
Shooting digital, you might actually tend to want to go with an even *higher* shutter speed, because a picture that looked sharp enough in a 4x6" print from film (all that most people ever did) is unlikely to do so in a 100% view on your computer monitor. On the other hand, as mentioned, SR helps a lot too. Plus, being digital, it doesn't cost me anything to just shoot a bunch and toss the ones that are blurry. So I have no problems regularly shooting at well below 1 / focal length.
Quote: Would that second multiplier be needed if using a made-for-dSLR lens in manual mode?
Not sure what you mean here. A 50mm lens is a 50mm lens, period. Doesn't matter is it was made for a DSLR or not, doesn't matter is you use it in manual mode or not. 50 = 50; bank on it. Whether the lens was made for film or digital does not affect a single aspect of the image or the picture taking experience in any way whatsoever.