See below:
frank theriault wrote:
On Apr 4, 2005 10:51 PM, David Oswald <[EMAIL PROTECTED]> wrote:
I'm curious. In the days of 35mm SLR's, Pentax had a few ED lenses; mostly fairly long telephotos.
Now that DSLR's are the up-and-coming thing, suddenly we're seeing ED glass in the 16-45, 50-200 (as yet unreleased), and the 12-24 (newly announced). AL elements have also become more commonplace.
So the question is, what's going on here? I see a few possibilities: * ED glass has suddenly become cheap enough to use in a broader range of lenses. * ED glass has become necessary to produce acceptible results with DSLR's. * ED glass has become enough of a recognized feature that using it pays dividends in improved lens sales. * Pentax has become committed to producing better zooms than ever before, possibly to try to close the door on 3rd party lenses (much like SMC does).
Much as I love my Pentax equipment, I can't help but wonder if the sudden proliferation of ED glass in Pentax's DA lenses is because without the ED glass the lenses on DSLR's wouldn't live up to the performance of their FA equivilants in 35mm format.
The same question could apply to the proliferation of AL elements in recent lenses, though this trend actually began back around the late 90's, so it's not as new of a trend.
I would love to hear that AL and ED elements common in recent Pentax lenses represent actual improvements to image quality, size, weight, and/or cost/value over lenses produced without these types of elements. Is this actually the case?
ED stands for what?
-frank
Egregious Dispersion.
Or, maybe Extra-low Dispersion... Yeah, that's it!
Helps solve any chromatic aberration problems that might otherwise occur, had they used regular optical glass in that particular optical design.
keith
