Re: slightly OT - lenses and closeup

Lenses can focus at any close distance you want as long as the lens
barrel can extend enough. The required extension is determined by the
focal length of the lens and the distance. As the photosensitive image
transducer size shrunk from 35mm to digital (most consumer digital
cameras have image sensors smaller than the image size of 35mm
format), required focal length to achieve the same angle of view is
much reduced. This in turn reduced the required lens extension
required to focus on a close subject, thereby allowing greater closeup
focusing capability with a limited physical dimension. It's more
analogous to the fact that 35mm cameras can usually focus at objects
much closer than what 8x10 cameras are capable of, rather than
advancement of optical technology.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)