Hi Fran,
Didn't wan't to sound to bully. I'm not always quite clear in mails myself. Yes, the latest new designs have benefitted of new glasses, ED and AL, however the computerization is equally important in the design. Today any feature of the lens, sharpness, contrast, flare,... can be quite thouroughly modelled. This is field I know some things about since the tools are basically the same as in my field of sounding the Earth with so called elastic waves. The tools where actually first developed within my field (geophysics and seismology) and two pioneers were Dziewonski and Gilbert and Gilbert was one of the very first (if not the first - havent checked it for a while though) to fomulate the problem. It all stems to the basics that waves whether elastic (in solid media), acoustic or optic all behave the same way for practical reasons when it comes to modelling.
Cheers,
Ronald
Ronald Arvidsson wrote:
Re: Pentax's sudden infatuation with ED glass.
Frantisek Tue, 05 Apr 2005 09:04:09 -0700
RA> I'm not sure you got my point. Design of optics is not necessarily a
Perhaps not :-) I am sometimes not sure if I even understand my point... <g>
Personally, I don't care much if the lenses are Fuji design or Hassy specified or Schneider or whatever... as long as they are good, which they are. I would be glad to own any Hasselblad :-)
One example of good lens is the Cosina 4/25mm - it is small and has that Leica look in pictures, at a fraction of the price.
RA> However, AL and ED designs are important to make more compact and RA> sometimes sharper optics, of course just the name is not worth anything
RA> but with modern computer technology the mix of different lenses with
RA> different refraction indexes make it much easier to make better and more
I am no expert here. But definitely we lately saw many extreme lenses not done before, full frame 12-24 zooms, 12mm rectilinear rangefinder lenses, etc. Most probably because of the things you mentioned. Aspheric surface is said to count as two normal surfaces regarding the designers' freedom, IIRC.
RA> compact optics with minimal input in the design. The best and sharpest
RA> optics is however a combination of good design and minute exactness.
RA> This last point is where the best glass is achieved from e.g. Pentax -
RA> also quality control.
I definitely agree. Even though I am no expert :)
In the end, it comes to good lenses or bad lenses, no matter what designations they have.
Frantisek
