About expensive lenses

On Tue, 30 Jan 2007 14:38:18 -0500, M-M wrote:

A Nikon 85mm 1.8 is $400.; an 85mm 1.4 is $1100.

Is the extra stop really worth all that extra expense? Why not just up
the ISO to compensate for those shots that really need the speed?

Am I missing something?

As others have pointed out, it's not a whole stop difference... it is
2/3 stop.

The 85 mm is often used as a portrait lens (on the old 35 mm cameras)
and for portrait work, the extra half stop can reduce depth of field a
bit. This way one eye can be in focus and the other out of focus...
just what some people want.

There could be quality of construction differences. Plus, the extra
glass requires additional compromises in optical design, usually
requiring extra elements. That increases the cost, and may (or may
not!) improve performance at equivalent f stops.

But in the end, it's only 2/3 stop. IMHO lots of people, especially
some amateurs, buy them for bragging rights. Why spend $400 if you can
spend $1100?

KS