Re: In-lens VR/I.S. must be eliminated

David J. Littleboy wrote:

>> the problem is that as the focal length of the lens increases, the
>> distance the sensor must move to compensate also increases and
>> there's a very real limit to what can be done.
>
> The _distance_ that the sensor has to be moved is the same whatever
> the focal length.

Totally incorrect!  Your statement would only be true if *ALL* lenses had
its final element set at exactly the same distance from the sensor plane,
which they do not!

> That's because IS is advertised to give you a fixed number of f stops
> improvement at any focal legnth.

Which is bogus and nothing more than marketing hype from both Nikon and
Canon.  And what is this "improvement" you speak of?  What scientific
measure is used to quantify a standard between all manufacturers?

> What has to increase with focal length is speed.

Yes, that is why you will see all future dSLRs caught up in a high-ISO
performance race.  The next Canon dSLR will s****t a 12,800 ISO for its
high
advertised usable ISO without much of an addition of more pixels.  It
wouldn't surprise me if the 1D Mk IV will top out at 12MPs.





Rita