And the biggest change was the ADI, which is a substantial thing to
add, an encoder had to be added, which is what drove the barrel and
distance window changes, and the circuitry. And yes, ADI is
documented as being part of the stabilization. The Sony service
manuals for the bodies cover how ADI is factored in. In default
mode, the body uses the accelerometers to do some stabilizing, this
is how it provides a stop or so of improvement to lenses like M42
lenses that have been mounted with no FL info or anything, you get
some results (this bit I don't think is covered much, but has been
pretty well determined through experimentation by folks).
The camera most likely defaults to a focal length and at this focal length,
you get full stabilisation. Using a lens at twice the default focal length,
you'll get 50% stabilisation, i.e. if you shake it four pixels, it will correct
two pixels. Using a lens at less than half the default focal length should give
better performance with SSS turned off, since the compensation will add
more net shake than the original shake (you shake it one pixel, the systems
corrects more than two pixels).
Maybe something for a rainy day, to find out by experimentation what the
default focal length approximately is. Unless it's written in a "service manual"...
If a lens has ADI it will
use the focus distance info too, this provides even better
improvement, it's just not required to get some improvement. But
still it is called out in the service manuals, and might be in some
of the books that come with the body or their website too, have to
dig for that. But still, it does get factored in.
I find that highly unlikely. First, to use the distance information at all,
it needs to establish the camera translation relative to the subject.
But you can only measure the acceleration. When you integrate the
acceleration, the constant velocity component is unknown. The camera
would have to make some wild guesses as to what constitutes zero
velocity. I don't see how it can do that in a generally reliable way.
Secondly, considering how aggressively Sony have advertised their
in-body stabilisation, would they really miss the opportunity to
tell everyone how they've made revolutionary breakthroughs in
camera stabilisation and hide it away in some "service manual"?
Anyway, the way to test this is shooting at close distances, say at
0.5x magnification with lenses with and without ADI and see if
there is a consistent difference over a large number of shots.
A peculiar characteristic would be that the subject in the centre of
focus is sharp but the subjects outside the plane of focus exhibit
motion blur. Not just single cases by chance, but fairly consistently.
Just my two oere
Erik from Sweden
