In article <8B8756A.00080033FA.uuout@fotobank.nl>, w.j.markerink@fotobank.nl says... (most deleted)

>Bob, I might have hassled you before about this subject in the past, >but do you think the gain is very much greater with mirrors?, say 4 >stops? Have you or any of your friends experience with such a combo?
>2 stops wouldn't justify the cost for me, but 4 stops would!
>Even a 1000/11 would become handholdable then....;-))

The gain with ANY lens that is suitable (not too heavy or too
physically long, which would negate much of the gyro effect)
is about 2 stops with the KS-4 (the KS-6 is so much heavier that
hand-holding it plus the camera and lens becomes iffy). This may
not sound like much until you think about it, but: 500mm mirrors
are marginal at 1/500th, and as a result, are limited to bright
days and fast films. With the gyro, using 100 ASA slide film is
possible on bright days, or you can shoot reliably on grey days
with 400 ASA. Even a 35mm f1.4 is interesting on a gyro - low
light photos on slow film, or VERY low light hand-held photos
on fast film become possible. A Rollei twin-lens, which I normally
consider useless as a hand camera, works well at 1/30th with
the gyro. Also, there are many situations where a tripod set-up
is awkward, and the gyro makes shooting without it possible.
Then there are the times when where you are is none too steady
(ladder, boat, plane, etc.), and the gyro can help. I have even
used it with super-wides and PC's for architecture - speeds up
shooting a lot when you are not using a tripod, and it helps
hold the camera steady for good framing and leveling. Heck,
gyro's aren't just for telephotos anymore...;-). And, yes,
it does make a 1000mm mirror hand-holdable (400 ASA, and bright
daylight, though..., but at least it's possible!).
Hmmm..., maybe it is just too useful to sell.......!
Hope This Helps