typical (small) motion blurring

Could anyone point me to any information on this question: If a
person is attempting and reasonably capable of holding a digital
camera steady, how many pixels of blurring, due to unintended motion,
would by typical for the image taken by the camera?

What if someone is under stress?

Thanks, J

On Mar 4, 5:43*pm, James1234567 wrote:
* * *Could anyone point me to any information on this question: If a
person is attempting and reasonably capable of holding a digital
camera steady, how many pixels of blurring, due to unintended motion,
would by typical for the image taken by the camera?

* * What if someone is under stress?

* * * * * * * * Thanks, J

That depends on the zoom and the pixels and probably a bunch of other
factors. It is fairly easy to hold a wide-angle lens steady in bright
light with a fast exposure. It is virtually impossible to hold a 300
mm lens under low light and long exposure steady by hand.

"Pooua" wrote in message
...
On Mar 4, 5:43 pm, James1234567 wrote:
Could anyone point me to any information on this question: If a
person is attempting and reasonably capable of holding a digital
camera steady, how many pixels of blurring, due to unintended motion,
would by typical for the image taken by the camera?

What if someone is under stress?

Thanks, J

That depends on the zoom and the pixels and probably a bunch of other
factors. It is fairly easy to hold a wide-angle lens steady in bright
light with a fast exposure. It is virtually impossible to hold a 300
mm lens under low light and long exposure steady by hand.

I would agree with this answer. There's also the size of the camera to take
into account. If it's a big heavy thing that doesn't have image
stabilization, it pays to check each picture straight after you've taken it
to see that the image hasn't blurred through camera shake (even in good
light).

I've often wondered whether image stabilization can degrade a picture
slightly, even though it can let you take a picture in slightly lower light
than would be the case with a camera that doesn't have image stabilization?
But even with image stabilization, it's probably not going to help much with
the example you give above about the 300mm lense in low light and with a
long exposure.

Pixie wrote:

I've often wondered whether image stabilization can degrade a picture
slightly, even though it can let you take a picture in slightly lower light
than would be the case with a camera that doesn't have image stabilization?

It usually does. That's why leaving IS running when on a stable tripod
will usually degrade the sharpness, which is why most modern IS
systems have some kind of tripod detection system and politely turn
themselves off when they think they're on a tripod. If you're lucky
:-)

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

"Chris Malcolm" wrote in message
...
Pixie wrote:

I've often wondered whether image stabilization can degrade a picture
slightly, even though it can let you take a picture in slightly lower
light
than would be the case with a camera that doesn't have image
stabilization?

It usually does. That's why leaving IS running when on a stable tripod
will usually degrade the sharpness, which is why most modern IS
systems have some kind of tripod detection system and politely turn
themselves off when they think they're on a tripod. If you're lucky
:-)

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]


Thanks Chris for this reply. I guess image stabilization is a much debated
issue, as in this discussion:

http://www.cheapshooter.com/2007/08/...e-or-a-gimmick

Your tip to turn off IS when using a tripod is most interesting. I found a
Wikipedia discussion that agrees with you:

"Most manufacturers suggest that the IS feature of a lens be turned off when
the lens is mounted on a tripod, as it can cause erratic results and is
generally unnecessary. Many modern image stabilization lenses (notably
Canon's more recent IS lenses) are able to auto-detect that they are
tripod-mounted (as a result of extremely low vibration readings) and disable
IS automatically to prevent erratic behavior by the IS and ultimately
reduced image quality."

http://en.wikipedia.org/wiki/Image_stabilization

You would think that IS would not have erratic behavior because the camera
is securely mounted on a tripod, I wonder why this happens? Would IS also
behave erratically if someone is able to handhold a small camera very
steadily? I have often rested a camera on a ledge or similar to keep it
steady, so I guess I should turn IS off then also?

When I went to buy a camera, they told me to buy one without IS if I wanted
the best image quality. But if you can turn IS off when you want to, it
might be better to get a camera with IS. However, it looks like you need to
know quite a lot about IS before using it, not everyone would think to turn
off IS when the camera is on a tripod!

Pixie wrote:
[]
You would think that IS would not have erratic behavior because the
camera is securely mounted on a tripod, I wonder why this happens?
Would IS also behave erratically if someone is able to handhold a
small camera very steadily? I have often rested a camera on a ledge
or similar to keep it steady, so I guess I should turn IS off then
also?

Of course, unless....

When I went to buy a camera, they told me to buy one without IS if I
wanted the best image quality. But if you can turn IS off when you
want to, it might be better to get a camera with IS. However, it
looks like you need to know quite a lot about IS before using it, not
everyone would think to turn off IS when the camera is on a tripod!

... unless the camera reliably senses a zero-vibration environment, and
turns the IS Off for you.

I have a number of cameras with IS, and find it helps me a lot,
particularly on the compact (small-sensor) cameras where you need to keep
to ISO 100 for the best images (otherwise noise intrudes), and hence
exposures are longer than you might otherwise want. Having in-lens IS for
my DSLR makes it easier to use as well.

Where IS may not help as much is where you need a fast shutter speed to
stop subject movement, although when photographing racing cars I find that
panning with the resulting blurred background produces images I like.

Cheers,
David

On Thu, 6 Mar 2008 09:09:21 +1300, "Pixie" wrote:


"Pooua" wrote in message
...
On Mar 4, 5:43 pm, James1234567 wrote:
Could anyone point me to any information on this question: If a
person is attempting and reasonably capable of holding a digital
camera steady, how many pixels of blurring, due to unintended motion,
would by typical for the image taken by the camera?

What if someone is under stress?

Thanks, J

That depends on the zoom and the pixels and probably a bunch of other
factors. It is fairly easy to hold a wide-angle lens steady in bright
light with a fast exposure. It is virtually impossible to hold a 300
mm lens under low light and long exposure steady by hand.

I would agree with this answer. There's also the size of the camera to take
into account. If it's a big heavy thing that doesn't have image
stabilization, it pays to check each picture straight after you've taken it
to see that the image hasn't blurred through camera shake (even in good
light).

I've often wondered whether image stabilization can degrade a picture
slightly, even though it can let you take a picture in slightly lower light
than would be the case with a camera that doesn't have image stabilization?
But even with image stabilization, it's probably not going to help much with
the example you give above about the 300mm lense in low light and with a
long exposure.


On the contrary. If your hand-held skills are admirable. I have obtained
1-second long tack-sharp exposures often with a 430mm lens. But you must turn
off IS from "continuous" mode and put it on "shoot only" mode. This way you can
stabilize your camera as much as possible on your own with the instant visual
feedback before the shot. You can't see how much you are shaking the camera with
IS turned on. Only during the actual exposure should you let the camera take
over.

The reason so many people get blurry images in low-light and longer shutter
conditions is that they are relying on IS to do all the work for them. Your
common and typical snap-shooters that are wanting an auto-everything camera.
With IS in continuous mode they might be shaking the camera more than the IS can
compensate for during the actual exposure. If you remove as much shake as you
can on your own the IS will gladly smooth out the rest. If you can't see the
shake you can't correct for it. Turn IS to "shoot only" mode to see the shake
and manually correct for it before you press the shutter release.

Blurry images are rarely ever the camera's fault. It's the person pretending to
be a photographer that's always the problem.

"David J Taylor" -this-
bit.co.uk wrote in m:

Where IS may not help as much is where you need a fast shutter speed to
stop subject movement,

It is still valuable in those situations, because what you wind up with is
blur only where the subject is moving, and not the whole frame. The former
is usually preferable. Whole-frame blurs (unless they come out looking
interesting, regardless) are more likely to be throw-aways than ones where
the background is stable but the moving subject is blurred. Sometimes a
little blur works nicely to emphasize the motion of the single object.

--


John P Sheehy

On Fri, 07 Mar 2008 23:03:17 GMT, John Sheehy wrote:

"David J Taylor" -this-
bit.co.uk wrote in m:

Where IS may not help as much is where you need a fast shutter speed to
stop subject movement,

It is still valuable in those situations, because what you wind up with is
blur only where the subject is moving, and not the whole frame. The former
is usually preferable. Whole-frame blurs (unless they come out looking
interesting, regardless) are more likely to be throw-aways than ones where
the background is stable but the moving subject is blurred. Sometimes a
little blur works nicely to emphasize the motion of the single object.

If you have to have a shutter speed fast enough to stop fast action in
sports like football, soccer, basketball, etc., then it's probably
going to be fast enough to stop your hand shaking also. That is,
unless your using a very long focal length lens and not just your
average 200mm or 300mm zoom. You're probably gonna want to use
something like 1/500 sec or even faster to freeze the subject in
action with those sports. So you're well under the reciprocal rule.
Even on a small sensor DSLR, the 300mm is around 450mm or so, which is
still under the reciprocal rule for 1/500 sec. So your odds are
pretty good of getting a sharp picture without IS or VR at those fast
shutter speeds.

Don't get me wrong, I love VR/IS. It expands the envelope of where
you can get an acceptable shot. But it doesn't really expand it very
much in the fast action direction. People have been taking great
pictures without it for years.

Steve

"dale_78" wrote in message
...
On Thu, 6 Mar 2008 09:09:21 +1300, "Pixie" wrote:


"Pooua" wrote in message
...
On Mar 4, 5:43 pm, James1234567 wrote:
Could anyone point me to any information on this question: If a
person is attempting and reasonably capable of holding a digital
camera steady, how many pixels of blurring, due to unintended motion,
would by typical for the image taken by the camera?

What if someone is under stress?

Thanks, J

That depends on the zoom and the pixels and probably a bunch of other
factors. It is fairly easy to hold a wide-angle lens steady in bright
light with a fast exposure. It is virtually impossible to hold a 300
mm lens under low light and long exposure steady by hand.

I would agree with this answer. There's also the size of the camera to
take
into account. If it's a big heavy thing that doesn't have image
stabilization, it pays to check each picture straight after you've taken
it
to see that the image hasn't blurred through camera shake (even in good
light).

I've often wondered whether image stabilization can degrade a picture
slightly, even though it can let you take a picture in slightly lower
light
than would be the case with a camera that doesn't have image
stabilization?
But even with image stabilization, it's probably not going to help much
with
the example you give above about the 300mm lense in low light and with a
long exposure.


On the contrary. If your hand-held skills are admirable. I have obtained
1-second long tack-sharp exposures often with a 430mm lens. But you must
turn
off IS from "continuous" mode and put it on "shoot only" mode. This way
you can
stabilize your camera as much as possible on your own with the instant
visual
feedback before the shot. You can't see how much you are shaking the
camera with
IS turned on. Only during the actual exposure should you let the camera
take
over.

The reason so many people get blurry images in low-light and longer
shutter
conditions is that they are relying on IS to do all the work for them.
Your
common and typical snap-shooters that are wanting an auto-everything
camera.
With IS in continuous mode they might be shaking the camera more than the
IS can
compensate for during the actual exposure. If you remove as much shake as
you
can on your own the IS will gladly smooth out the rest. If you can't see
the
shake you can't correct for it. Turn IS to "shoot only" mode to see the
shake
and manually correct for it before you press the shutter release.

Blurry images are rarely ever the camera's fault. It's the person
pretending to
be a photographer that's always the problem.


Thanks for this helpful information. I think camera owners need to know
whether or not image stabilization (referred to by Sony as "steady shot" or
"anti-blur) turns itself off automatically when zero movement is detected.
This point has been discussed he

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00D0Ik

It seems that not all IS systems can detect when a camera is on a tripod
(perhaps not all older systems turn off automatically when zero movement is
detected). How do you know for sure whether your IS system turns off
automatically when your camera is on a tripod if the instruction manual
doesn't tell you (as is the case with some compact cameras)?

Perhaps the only way is to run a few tests with your own camera, both with
IS on and IS off when your camera is on a tripod and compare the results. In
my case, I found that having IS turned off produced slightly better results
than when IS was on (when the camera was on a tripod). So, I will turn IS
off in future when the camera is on a tripod.

Another point, even when the camera is on a tripod, it may pay to use the
self timer function, I have found using this improves the clarity of
pictures slightly.