"David Littlewood" wrote in message
In article , Tony Polson
Perhaps my comments were a bit harsh. I just took offense to the
suggestion that it was ignorant to use the widely accepted and
understood term "prime lens".
But "prime lens" is NOT a "widely accepted and understood term".
Because of the history of its use, it is essentially ambiguous. It
has only been used as a descriptor for all fixed focal length lenses
in recent times, and only by people who are unaware of its prior
usage, which was as a descriptor for a "high quality" subset of fixed
focal length lenses. You might be too young to recall this.
There was no accepted definition of which fixed focal length lenses
were "prime" and which were not. It was merely an attempt by
marketing people to promote some lenses as being "better" than others,
the implication being that one brand was "better" than another because
of the "high quality" of their "prime" lenses.
The terms "high quality", "better" and "prime" are all essentially
meaningless unless backed up with something more objective, repeatable
and reliable. As we all (should) know, comparisons between lenses are
qualitative at best.
The most commonly used "objective" comparator - MTF - was never
intended for making such comparisons. It was intended as an aid to
lens designers and nothing more. As a result it misleads far more
than it ever informs, and those who claim it is of any real value when
comparing photographic lenses are suffering from delusions.
I agree with the first part of the above. The only point in which my
understanding differs is that the traditional use of the term "prime" was
in the sense of "primary" as opposed to secondary or auxiliary optical
components such as tele-converters, wide angle attachments, close up
lenses and the like. Thus prime as in the Latin "primus", first or
This is the interpretation given in the more rigorous works on photography
I consulted on this issue when the point was debated here (ad nauseam)
several years ago. (Anyone remember Neil Harrington?)
I see him every time I shave. :-)