Quote Originally Posted by Common Rose
The book is talking about slr. For dslr, I think that will translate to 160-180mm?
Whilst the field of view may translate into the 1.5x or 1.6x crop factor, the lens essentially still behaves like the original focal length. So if a 180mm lens becomes a 270mm lens on a DSLR, the handholding speed can still remain at 1/180s via the reciprocal f-length rule of thumb for the shutter speed.