Re: Confused about "Digital" Lens

According to Pete D <no@xxxxxxxxx>:

<plastic_razor@xxxxxxxxx> wrote in message
news:1157948422.750062.120810@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On a few occasions, I've seen references to "digital" lenses. These
are lenses that are optimized to have photons hit the digital sensor at
a perpedicular angle. Allegedly, lenses optimized to work with digital
sensors would produce better results for a digital camera than a lens
designed originally with film in mind. It seemed to make sense to my
feeble mind.

It does not seem to make much difference in reality. I'm using
a bunch of lenses designed for film on my D70, and have observed no
problems with them. I would expect the most possible problems of this
sort on extremely wide angle lenses -- but the ones most likely to
generate problems would be the ones which also need the mirror locked up
to allow the lens to mount and function (thinks like the old 8mm Fisheye
lens from Nikon stuck so far back that they would also impact the mirror
if it were not locked up.

So now I'm wodnering why I don't see Nikon or Canon lenses with these
"digital lens" designations. Is it because these companies are making
compromises for the sake of compatibility with film cameras? Or is it
because this whole "digital lens" thing is just a load of crap?


Canon have their EF-S range that is digital only. Nikon I am not sure about.
Pentax has their digital only range.

So does Nikon -- in the "G" series lenses. The 18-70mm "kit"
lens for the D70 and D200 is one example of this -- and it mounts far
enough from the sensor so there is no mirror interference problem, and
the actual angle of the light hitting the sensor is not nearly as wide
as the lens' focal length would cause you to expect. A real 18mm lens
would have to be mounted so far into the body that the mirror would be
hit. However, the design of the 18-70mm is such that this is not a
problem.

One interesting feature of the new "G" series lenses is the lack
of an aperture ring. The camera body is expected to command the lens to
the proper aperture -- which makes this lens useless on a film body --
aside from the feature mentioned in the following paragraph, which
applies to the Nikon lenses for digital as well.

They have a smaller image circle so can be made smaller and ligher and will
vignet on a larger sensor camera.

And Nikon -- so far -- has standardized on a 1.5 crop factor
for *all* of their DSLRs.

Enjoy,
DoN.

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