Sigma 18-200 & OS

Have just replaced my Sigma 18-125 with an 18-200 with Optical
Stabilisation. When I go walkabout I always have a mono pod with me but
the Sigma manual suggests switching off the OS when on a tripod. Does
the body of the lens/camera/hand absorb some of the vibration as a
cushioning effect ? Would love to know if it is only a suggestion by
Sigma or if one can damage the motors when switched on while on a 'pod.

I do a fair amount of mountain bike and soccer photos of my two children
& the mono pod is almost permanently attached to the D70.

The main reason for the 'pod is that I adjust the camera for height &
then just have to rotate the camera to pick up the shot

I must add that this particular lens feels far more solid, rugged &
responsive than my Sigma 18-125. ( Also a great carry lens for the price )
The only schlep is that I have to replace the polariser & my infra red
filter with 72 diam. units.

I now have to find buyers for a boxed Cosina 17-35 AF, Tamron 70-300 AF
& the Sigma 18-125 .... all Nikon mount & in mint condition with UV
cover glass & Hoya polarisers.

Bernard.

On Nov 19, 10:04 pm, Bernard Rother
wrote:
Have just replaced my Sigma 18-125 with an 18-200 with Optical
Stabilisation. When I go walkabout I always have a mono pod with me but
the Sigma manual suggests switching off the OS when on a tripod. Does
the body of the lens/camera/hand absorb some of the vibration as a
cushioning effect ? Would love to know if it is only a suggestion by
Sigma or if one can damage the motors when switched on while on a 'pod.

I do a fair amount of mountain bike and soccer photos of my two children
& the mono pod is almost permanently attached to the D70.

The main reason for the 'pod is that I adjust the camera for height &
then just have to rotate the camera to pick up the shot

I must add that this particular lens feels far more solid, rugged &
responsive than my Sigma 18-125. ( Also a great carry lens for the price )
The only schlep is that I have to replace the polariser & my infra red
filter with 72 diam. units.

I now have to find buyers for a boxed Cosina 17-35 AF, Tamron 70-300 AF
& the Sigma 18-125 .... all Nikon mount & in mint condition with UV
cover glass & Hoya polarisers.

Bernard.

It's not a question of damage, it's a question of the stabilization
'working' to compensate for movement which is not actually occurring.
It can cause the mechanism to move when the camera is in fact still,
resulting in lower quality images.

I can't speak any more technojabbery than that, but the same principle
apparently applies to my Canon lenses, as I was given exactly the same
advice.

On Mon, 19 Nov 2007 22:14:59 -0800 (PST), BD wrote:

On Nov 19, 10:04 pm, Bernard Rother
wrote:
Have just replaced my Sigma 18-125 with an 18-200 with Optical
Stabilisation. When I go walkabout I always have a mono pod with me but
the Sigma manual suggests switching off the OS when on a tripod. Does
the body of the lens/camera/hand absorb some of the vibration as a
cushioning effect ? Would love to know if it is only a suggestion by
Sigma or if one can damage the motors when switched on while on a 'pod.

I do a fair amount of mountain bike and soccer photos of my two children
& the mono pod is almost permanently attached to the D70.

The main reason for the 'pod is that I adjust the camera for height &
then just have to rotate the camera to pick up the shot

I must add that this particular lens feels far more solid, rugged &
responsive than my Sigma 18-125. ( Also a great carry lens for the price )
The only schlep is that I have to replace the polariser & my infra red
filter with 72 diam. units.

I now have to find buyers for a boxed Cosina 17-35 AF, Tamron 70-300 AF
& the Sigma 18-125 .... all Nikon mount & in mint condition with UV
cover glass & Hoya polarisers.

Bernard.

It's not a question of damage, it's a question of the stabilization
'working' to compensate for movement which is not actually occurring.
It can cause the mechanism to move when the camera is in fact still,
resulting in lower quality images.

I can't speak any more technojabbery than that, but the same principle
apparently applies to my Canon lenses, as I was given exactly the same
advice.

There's no cut and dried answer for this one. Some DSLR IS lenses and P&S
systems dampen the stabilization to nothing when it can't detect any motion.
Others sit there "testing for it". Moving on occasion to see if there's any
motion in the air, so to speak. Earlier models of the same lens may not have the
same type of IS in them as later models.

The best way to tell in a P&S camera or a dSLR with live-view is to mount the
camera on a very sturdy tripod. Zoom the lens to the absolute max, even using
max digital zoom on your P&S if you have it, then focusing on some distant
object with high contrast details. You're trying to magnify any motion as much
as possible if and when it occurs. Allow the camera to settle down for at least
2 seconds (I have found that most self-dampening systems need a 2 second delay
to quiet down). Then watch in the LCD or EVF for the slightest signs of any of
that detail shifting over any of the display pixels over a minute of time. If
the camera is setting on a wooden floor be careful to not even shift your
weight, as this might be enough motion imparted to the tripod, to camera, to
wake-up the IS and then it'll have to settle down again. If you detect no motion
in the view then there's no reason to turn it off. If your live-view or EVF
image occasionally jogs to the side or is very slowly drifting all the time then
remember to turn yours off when tripod mounted.

If you don't have the advantage of real-time feedback of live-view or an EVF
then you can always take a 30-second or one minute exposure and see if there's
any blurring in your image. Again, being careful to not even shift your weight
when near the tripod. And use a self-timer release with at least a 2 second or 5
second delay so all tripod shake can die down as well as the IS servos.

Luckily my latest P&S super-zoom has the kind that goes to sleep after 2 seconds
of no motion. I think this is by far the best way to have it implemented. Then I
don't have to worry about it when tripod mounted. And if by chance the tripod is
disturbed by a breeze, or the ground shifts from a heavy truck rolling by on a
nearby road (yes, their passing can cause that much motion in the ground, go
read up how holographers have to deal with traffic a block away), or I
accidentally bump into it, then it's great if it kicks into gear as a quick
stabilization backup plan.