--- Bob <[EMAIL PROTECTED]> wrote:
> I may be wrong, but it is my understanding, and
> opinion, that all of
> these lenses that are designed for digicams are
> marginal at best in full
> frame applications like film or full frame sensors.
>
> Since the typical digital image sensor is in the
> center of the "frame"
> little has been done to keep sharpness at the edges
> as with non digital
> lenses.
I don't think you can make a blanket statement like
that. First off, many, if not most, of the lenses
designed specifically for DSLRs don't even cover a
full frame image. They're designed with an image
circle large enough to cover a 1.5 - 1.6 crop factor
sensor. So the corners are used in the image, and the
vendors take as much care with the sharpness there as
their design and market philosophy, and price point,
dictate.
For the "Digital" lenses that do cover a full frame,
again, sharpness at the corners is going to vary,
depending on the manufacturer and price point. Sigma's
DG lenses, for example, are described as "ideal lenses
for digital SLR cameras." I think the quality at the
edges is as good as or better than any of Sigma's
"non-digital" lenses at similar price points. (Sigma's
DC lenses, on the other hand, are specifically
designed for the smaller format sensors.
Similarly, Tamron's Di II lenses are for smaller
sensor cameras only. Their Di lenses are full frame,
and I've seen no indication that they're any worse at
the edges than Tamron's similar "non-digital" lenses.
If you have any test reports or other evidence to
argue differently, I'd be interested in seeing them.
Bob Meyer
I don't suffer from insanity... I enjoy every minute of it.
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