On 5/28/2015 4:48 PM, Mike Gordon via olympus wrote:
...
Or I. S. Moose writes:
<Sure - but - different IS systems do best at different FLs, or may level the
difference between FLs. It's possible for IS to trump geometry. I have shots of flowers
where <the same flower, shot at 43 mm and 1/320 in 12-50 macro mode is
indistinguishable in this regard from 252 mm (500 mm FF eq!) at 1/125. Neither has any
visible <motion blur.
Point of factoring in the IS ability is well taken--but---Longer FL magnifies
the effect of some cam displacments so IS would have a harder time taming them.
You make an assumption of inadequacy without evidence.
In round numbers the EM-5 11 IS provides about 3 stops stability over 1/FL rot
(rule of thumb) on dpreview test at 24mm and 200mm.
That the effectiveness is the same at both FL extremes should be a clue that its design is sufficient to deal with long
FL magnification of camera movement. My own experience says it is certainly up to 300 mm. That the camera allows setting
FL up to 1000 mm, it's not an unwarranted assumption that that is the design end point. Certainly a couple of quick
tests shots with the 500/8 look like the IS worked, but how to tell which parts, I don't know.
One may speculate forever on whether a particular engine will propel a particular car through the 1/4 mile in less than
a particular time. But none of that matters after the test has been made. The theoretical speculation must adjust to the
experimental results.
It is certainly possible in theory, given adequate motion sensing, sensor movement speed, accuracy and travel, for IS to
fully compensate for geometry up to any given design FL. Have you looked at the comparative shots PiitP Moose posted? I
suggest that they show a triumph of IS over geometry up to at least 300 mm. I didn't do anything special when I took
them, just some shots wandering around an Asiatic botanic garden.
Of note sony does NOT stabilize non system lens that does not report focusing
distance to cam in x/y planes--thus only 3 axis stabliization. X/Y displacment
especially imp't for macro. Any idea if Oly has
5 axis stabilization for lenses on adapters? I have wondered about that for
ages. Anyone? Speculation welcome.
The OM-Ds have CD AF, so it has the capability to know what parts are in focus. I can imagine a computational system
that knows both the actual FL of the lens, and thus the on sensor movement to be expected at infinity focus. By
comparing that to the actual movement, your frequently referenced friend, geometry, makes it possible to calculate a
focal distance.
What they are actually doing, I have no way of knowing. They say nothing about IS being limited in any way with adapted
lenses.
Non Euclidean Moose
--
What if the Hokey Pokey *IS* what it's all about?
--
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