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Image Stabilization vs. High
Image Stabilization (also called Anti-Shake,
Vibration Reduction) is a technology present
in some digital cameras that moves either
a lens element (optical image stabilization
or O.I.S. or simply, IS) or the image sensor
(CCD Shift) to compensate for camera shake.
In doing so, it eliminates, or reduces the
likelihood of obtaining, blurred images
due to camera shake.
High ISO (also called Intelligent ISO,
Anti-Blur, Picture Stabilization, Digital
Image Stabilization, Electronic Vibration
Reduction, etc.) is a scene mode that favours
the use of a high ISO so as to permit the
camera to use a shutter speed fast enough
to eliminate, or reduce, the effect of camera
shake and/or subject movement.
There is some controversy -- and a lot
of confusion -- around the use of the term
"IS" or "Image Stabilization."
In this article we take a (calm and) detailed
look at how IS and High ISO work, their
advantages and disadvantages, and what consumers
should really be looking for.
To fully understand why we need Image Stabilization
or High ISO -- and their importance to photographers
-- we first need to understand the two main
reasons why we usually get blurred pictures.
REASON #1: CAMERA
Whenever you press the Shutter-release
button to take a picture, you move the camera,
even if imperceptibly. You may not be aware
of this slight movement and, depending on
how steady your hands are, your images may
suffer from some amount of blurriness.
If your hands are rock steady, plus you
squeeze the Shutter-release button ever
so gently, the blur may be so slight that
it is visually unnoticeable in your images.
If, however, you do not have steady hands
and/or you ram the Shutter-release button
forcibly down every time you take a picture,
chances are good the camera will "shake"
when you press the Shutter-release button
and you end up with blurry images.
The likelihood of this "camera shake"
increases as the focal length used increases
(e.g. when you zoom). As the focal length
increases, the slight movements of the camera
get magnified so that blurred images will
more easily result.
REASON #2: SUBJECT
The second reason why images come out blurred
is simply because your subject moves during
exposure (the subject moves while the shutter
is open and the camera is still recording
If you look at the individual images of
a movie of a moving subject, you will notice
that almost all the images are in fact blurred!
This is because the subject moved during
exposure. However the frames of a movie
are played back so fast (about 30 frames
per second) that our eyes cannot necessarily
register each single blurred image and so
overall the movie looks sharp to us.
Long ago, a subject would be admonished
to "sit still and do not move"
for the duration of an exposure -- which
could last a couple of seconds to minutes.
Since the camera was on a tripod, there
was little chance of camera shake. So the
only risk was that the subject moved and
a blurred image would result due to subject
SHAKE: FAST SHUTTER SPEED VIA HIGH ISO
Before the advent of Image Stabilization
technology, the "cure" for camera
shake was to:
1. Place the camera on a sturdy tripod
(or some other level surface) and use a
Shutter-release cable, a remote controller
or the self-timer to trigger the shutter.
3. Use a fast enough shutter speed to eliminate
the need for image stabilization. If the
shutter speed used is not an important photographic
consideration (i.e. you are not trying to
freeze action using a fast shutter speed
or depict action using a slow shutter speed),
then using a fast enough shutter speed means
that the effect of camera shake will not
have time to register on the picture.
If you use a shutter speed that is faster
than the movement of the camera, camera
shake will not be a problem because the
image will have been taken (shutter will
have opened and closed, and the scene recorded)
even before the camera movement can register.
Reciprocal of Focal Length Rule of Thumb
The rule of thumb here is that to be able
to handhold a camera safely (i.e. without
incurring camera shake), you would need
to use a shutter speed that is the reciprocal
of the [35mm equivalent] focal length of
the lens used. This is not complicated to
understand: For example, when you use a
[35mm equivalent] focal length of 55mm,
you would need a shutter speed of 1/55 sec.
(or faster) to be able to safely ignore
camera shake; when you zoom to a focal length
of 100mm, you would need a shutter speed
of 1/100 sec. or faster; further zooming
to (or using) a focal length of 420mm, you
would need a shutter speed of 1/420 sec.
Note that using a fast enough shutter speed
is not the same as "image stabilization."
In fact, there is no need to stabilize the
image, and hence no need for image stabilization.
Using a fast enough shutter speed eliminates
the need for Image Stabilization.
If your camera meters the need for a slow
shutter speed which will cause camera shake,
there are two ways to switch to a faster
1. Open up the aperture. Opening up the
aperture (makes the hole bigger and therefore)
allows more light to come in and so reduces
the time the shutter needs to stay open.
["Shutter speed" is simply the
time the camera keeps the shutter open.]
2. Often, especially in low-light situations,
this will not even give you a fast enough
shutter speed to hand hold the camera, so
the second way is to use a higher ISO.
At a fixed aperture (let's say the aperture
is already opened to its max.), a higher
ISO allows the camera to use a faster shutter
speed. If that shutter speed is fast enough
for safe hand holding the camera (using
our reciprocal of focal length rule of thumb
mentioned above), then there is no need
for image stabilization. This is the premise
upon which High ISO, Intelligent ISO, Picture
Stabilization, Anti-Blur, Digital Image
Stabilization and Electronic Vibration Reduction
(to list only the most common High ISO terms)
rely on to do away with the need for equiping
the camera with an image stabilization technology.
So, before the advent of IS, photographers
were already manually upping the ISO so
that they could use a fast enough shutter
speed that will counter camera shake. The
High ISO scene mode simply automates this
process, i.e. by selecting this scene mode,
you are telling the camera to go ahead and
select a high ISO.
High ISO vs. Auto ISO
High ISO scene mode favours a high ISO.
Contrast this scene mode to Auto ISO which
always favour a low ISO.
Typically a camera will restrict the ISO
values it will use in Auto ISO to those
that will give an acceptable level of image
quality. So, for example, even if your camera
has ISO range from 100 to 1600, Auto ISO
may be restricted to ISO 100 to 400 only.
Favouring a low ISO means that the camera
can deliver lower noise, retain more image
details, and therefore better image quality.
High ISO, on the other hand, will typically
start with the highest ISO (in our example,
ISO 1600), and couldn't care less about
the noise issue, leaving it to the in-camera
noise reduction software (really, firmware)
to reduce the noise.
Noise & Image Detail Loss
There is currently one problem with the
High ISO scene mode: noise (*1).
The noise introduced at high ISOs is exhibited
as ugly blotches of colours you see in your
images. Now, you know where these come from!
Also, in trying to remove the noise, the
noise reduction software in your camera
also unfortunately removes fine details
in your images. Now you know why some of
your high ISO images also have this "watercolour
So while photographers gain a benefit (reduction
of camera shake, hence less blurry pictures),
they also pay a heavy price to use High
ISO: noisy images and loss of image details
However, if you only print 4x6 in. images,
or display small size for the Web, then
the noise present at high ISOs might not
be too apparent at these small sizes, and
you may get away with using it.
More advanced photographers typically use
digital cameras with manual modes and rarely,
if ever, use scene modes, preferring to
set the exposure (shutter speed, aperture
and ISO) themselves. And when they use a
high ISO, they expect noise and typically
post-process their images in a Noise Reduction
software to remove the noise (to a certain
extent, still subject to image detail loss).
High ISO is a scene mode. It is not Image
Stabilization technology, and it is incorrect
to use the term IS when referring to it.
Marketers do that all the time, so it is
incumbent upon us as informed consumers
to be able to tell the difference between
To summarize: High ISO is a welcomed and
useful scene mode, especially for the point-and-shoot
crowd who do not know -- or care to know
-- how to manually select a fast shutter
speed or manually select a high ISO; or,
as is often the case, they use a digital
camera where there is no manual mode to
enable them to do so. The benefit is reduced
camera shake; the price is noise (*1).
SHAKE: IMAGE STABILIZATION
As we mentioned earlier, Image Stabilization
is a technology that moves a lens element
(Optical Image Stabilization, or O.I.S.)
or the image sensor (CCD-shift IS) to compensate
for slight movements of the camera.
So, say we are using a focal length of
60mm, the reciprocal of focal length rule
of thumb says we should be using a shutter
speed of 1/60 sec. to eliminate camera shake.
But if there is not enough light, the camera
might need to use a slower shutter speed,
say 1/15 sec., for a correct exposure.
At this slow shutter speed and without
using a tripod, we will obtain a blurred
image if we hand hold the camera. But, with
Image Stabilization, we are now able to
hand hold the camera without worrying about
camera shake (1/15 sec. is 2 stops slower
than 1/60 sec.).
If the light level falls further and the
camera now needs an even slower shutter
speed, say of 1/4 sec. (that's 4 stops slower
than 1/60 sec.: 1/60 sec., 1/30 sec., 1/15
sec., 1/8 sec., 1/4 sec.), Image Stabilization
will not help us eliminate camera shake
in this case. It will, however, reduce its
Note that IS works irrespective of the
ISO used. Whereas High ISO forces you to
use a high ISO (with resulting high noise
and image degradation issues *1), IS allows
you to keep at a low ISO while still reducing
camera shake (thus keeping maximum image
quality). That is, it does not mess with
your selected exposure settings (you keep
the shutter speed, aperture and ISO you
want to use).
So, as you can see, IS is a wonderful technology
worth having in any digital camera. It can
make a big difference in being able to hand
hold a shot either in low-light or when
using long focal length. You can gain up
to 2 or 3 stops. You can, of course, combine
the use of High ISO and IS.
Let's look at some practical considerations:
- If you take mostly landscape photos
and your camera is almost always on a
tripod, then image stabilization will
not help you nor is it needed (in fact,
most digital cameras require you to turn
image stabilization OFF when placing the
camera on a tripod).
- If you take pictures mostly outdoors
in sunny situations, or in studios with
controlled lighting, you will almost always
be using a shutter speed appropriate for
the focal length -- and so image stabilization
is not needed.
- If you like to take pictures at long
focal lengths (telephoto shots) and hand
hold your camera, image stabilization
is very useful to help reduce the likelihood
of blurred images due to camera shake.
- If you like to take pictures indoors
in low-light situations where the subject
is not moving, image stabilization is
- However, Image Stabilization will NOT
negate the effect of subject movement.
Since IS only counters the effect of camera
shake, it does not counter blurriness
caused by subject movement.
Either a digital camera is equipped with
this IS technology or it is not. Anything
else is a misuse of the term.
IS is a technology worth having in any
digital camera, and worth the extra cost.
There are a number of ways to counter subject
1. Use a shutter speed faster than the
movement of the subject -- fast enough to
"freeze the action."
This shutter speed would be dependent on
the type of movement in question: for example,
to freeze a runner in action, a shutter
speed of 1/125 sec. might be adequate; to
freeze a racing car in action, a shutter
speed of 1/1500 sec. or faster might be
2. Another way to freeze a moving subject
is to use flash. Nothing is faster than
light and so using flash will always freeze
the subject in action (as long as the subject
is within the flash coverage). But flash
is not allowed in all venues, nor is it
always desirable because the result of using
the on-camera flash is often images that
do not look very pleasant.
MOVEMENT: FAST SHUTTER SPEED VIA HIGH ISO
Most photographers will first open up the
aperture to use a faster shutter speed.
If this still does not give a correct exposure,
they will then use a higher ISO.
As we have seen, using a high ISO allows
us to use a faster shutter speed. By boosting
the ISO high enough, we may be able to use
a shutter speed fast enough to freeze the
action and thus eliminate blur caused by
the movement of our subject.
So, say our subject is a toddler running
excitedly around the room and we need a
shutter speed of 1/125 sec. to freeze the
action. But indoors, there may not be enough
light and the camera needs a shutter speed
of 1/30 sec. for a proper exposure.
This slow shutter speed is a double problem:
not only is it too slow to freeze the action
of our toddler, it may also be too slow
for us to safely hand hold the camera (assuming
we are using a focal length of 60mm and
thus require a shutter speed of at least
1/60 sec. to eliminate camera shake).
If we can boost the ISO up by 2 stops (say
we are currently using ISO 100, so ISO 200
would give us 1 stop exposure gain, and
ISO 400 would give us a 2 stop exposure
gain). At ISO 400, we can now use a shutter
speed of 1/125 sec. (1/30 sec. to 1/60 sec.
= 1 stop; 1/60 sec. to 1/125 sec. = another
stop; total = 2 stops). Now not only will
we be able to freeze the action, but we
have also eliminated camera shake! All without
the need for image stabilization!
Some photographers will read this and conclude
that High ISO is better than IS. That is
what many marketing messages surreptitiously
try to get across. What they do not tell
you is that using a high ISO introduces
noise in your pictures.
Unless your digital camera has a low-noise-high-ISO
characteristic (and to date only one camera
manufacturer can truthfully boast to have
achieved this *1), any use of a high ISO
will result in either unwanted noise and/or
unacceptable loss of image detail.
Advertisements and specs boasting about
the availability of high ISOs in a digital
camera without this low-noise-high-ISO characteristic
are therefore to be read in its proper context.
The availability of a high ISO can mean
the ability to get a shot where otherwise
you might not be able to do so because of
the low light level. The average photographers
using a Point-and-Shoot digital camera may
never print beyond 4x6 in. and noise (and
loss of image detail) may not be as big
an issue as it is for more advanced photographers.
DOES HIGH ISO
REPLACE IMAGE STABILIZATION?
So, is High ISO better than Image Stabilization?
It looks like it on paper, doesn't it?
If you boost the ISO and use a fast enough
shutter speed, you can counter the effect
of both subject movement and camera shake.
Image Stabilization can counter only camera
shake. So, maybe after all, we do not need
If High ISO sounds too good to be true,
that's because it is!
We mentioned 2 problems with using a high
ISO and we'll repeat them here for emphasis
(because the marketing ads won't), and add
2 more reasons why High ISO is not all the
solution it promises to be:
1. Using a high ISO introduces noise in
your photos. Noise shows itself as unwanted
and ugly blotches of colour all over an
Compact consumer digital cameras use very
small image sensors that are characteristically
prone to lots of noise when using high ISOs.
[Most Digital SLRs use large image sensors
which usually have a low-noise-high-ISO
characteristic and therefore the use of
high ISOs do not result in unacceptable
level of noise.]
2. In-camera noise reduction is too often
accomplished at the expense of detail: we
remove noise by smoothening out the pixels
and in doing so we also smooth out details.
The result is a watercolour-effect image.
3. You may not want to use a high ISO and/or
a fast shutter speed. Say, you are trying
to depict motion (e.g., a waterfall) and
require a slow shutter speed for that. In
this case, you want the water of the waterfall
to look blurred and cloudy (depicting motion),
but want the rest of the scene to be tack
sharp. High ISO wants to give you a fast
enough shutter speed -- and it may be too
fast to depict motion.
4. In very low light situations, you may
be using the largest aperture, highest ISO
and still end up with a shutter speed too
slow for safe hand holding the camera. In
this case, IS may well save the day.
Remember, High ISO is just a scene mode
and, like all scene modes, can be manually
set on [almost] any digital camera. In other
words, it is -- and has always been -- available
in digital cameras. Simply set a high ISO
yourself manually. After all, there's not
much more effort required to select "ISO
800" as opposed to selecting "High
ISO" in the MENU, is there?
WHAT'S ALL THE
Some readers may wonder, "What is
all the fuss about? As long as the use of
IS or High ISO results in images that are
not blurred, why worry about the correct
use of the term IS? Why worry at all which
is being used? After all, doesn't the average
consumer only care about the final results,
however they are achieved?"
For arguments' sake, we'll grant you 50%
of that reasoning.
However, note that margarine is not called
butter, though consumers use both interchangeably
to "butter" their bread.
Bottled spring water is not the
same as bottled distilled water,
even though consumers ingest both without
fully understanding the difference.
You could use a wrench to hammer nails
in [guess who has shamefully done this only
just recently?], but it is not sold as a
There are differences in these "similar
use" products that are important enough
that their respective industry requires
that a distinction be made in their labelling.
Likewise, High ISO is not IS. High ISO
is simply using a high ISO. This in turn
may or may not result in the use of a shutter
speed fast enough to eliminate the need
for IS. But, in this writer's opinion, it
is not IS, does not replace IS, and should
not be marketed as IS.
HOW ABOUT HAVING
Isn't the ideal digital camera then one
that has both IS and High ISO capability?
Yes, but hold on a minute. We have been
discussing the wrong issues so far. Because
marketers lead you through this garden path,
we have also followed it so as to clarify
But now, it's time we come to the crux
of the real issue.
Remember, High ISO is simply a scene mode
and all digital cameras offer high ISOs,
so there is really no issue here. All digital
cameras today offer a High ISO mode (though
maybe called one of the other variations);
not all digital cameras offer IS.
So, if all digital cameras offer High ISO
scene mode, all we have to decide really
is whether we want our digital camera to
have IS or not. Right?
Though, there's something else to consider:
since IS handles only camera shake, we still
need the possibility to use a high ISO (for
a fast enough shutter speed to counter subject
movement). But at high ISOs, noise is too
high and image quality degrades, so depending
on what kind of photographer you are, High
ISO may be a useful or useless feature.
But wait, there is a digital camera that
has a low-noise-high-ISO characteristic
image sensor! Now High ISO suddenly becomes
practically useful! With such a digital
camera, you can up the ISO and take low-light
pictures without suffering image degradation.
Alas, currently this digital camera (*1)
is not equipped with IS.
So now we see the real issue: do we choose
a digital camera with IS (but where the
image quality degrades at high ISOs) or
one with a low-noise-high-ISO characteristic
(but no IS)?
Adding IS to a digital camera is not a
difficult matter. More and more digital
cameras (even from obscure brands) now has
this technology and it is only a matter
of time before IS becomes widely available
in all the major brand digital cameras.
More difficult is designing and building
an image sensor with low-noise-high-ISO
characteristic. This is the problem of using
a high ISO; the question that consumers
should be asking is: how is the image quality
at high ISOs?
(*1) Currently in the compact consumer
digital cameras, only Fujifilm digital cameras
with their Super CCD HR image sensors have
low noise at high ISOs, making them the
undisputed king of low-light photography.
We can divide digital cameras as falling
into one of 3 (IS/High ISO) categories currently:
- Have High ISO with unacceptable high
noise and image detail loss; no IS.
- Have IS, plus High ISO with unacceptable
high noise and image detail loss;
- Have High ISO with very low noise; no
Here are the categories summarized in a
table, with a fourth one added and highlighted
Cameras in Category #1 are good for sunny
shots (since the use of a high ISO is then
not required and shutter speed will almost
always be fast enough to eliminate camera
Cameras in Category #2 have IS but don't
try to use their High ISO feature too much
because the resultant images are too noisy
for many photographers. For small prints
and Web display, they are more than adequate.
Cameras in Category #3 do not have IS but
have low-noise-high-ISO image sensors that
give you low noise at high ISO values. They
are perfect for low-light photography.
What we want are digital cameras in Category
#2 and #3 to combine their respective strengths
and create a new Category #4: i.e., be equipped
with IS and image sensors with low-noise-high-ISO
characteristics (i.e. produce very low noise
when high ISOs are used).
So, look out especially for new digital
camera models in the 3rd category [Fujifilm]
coming out with IS; and, more difficult
to achieve, cameras in the 2nd category
[Panasonic, Canon, Kodak, Nikon, all the
rest] using a low-noise-high-ISO image sensor.
WHICH ONE TO BUY?
So the real question is not whether to
choose between IS or High ISO. It is to
choose between IS and Low-Noise High
ISO. Most every digital camera now offers
High ISO, but only one offers low noise
And, the answer will depend on your type
Image quality is most important to me so
I favour a digital camera with low-noise-high-ISO
characteristic (Category #3). I have a pretty
steady hand, and I can always use a tripod
or other level surface for image stabilization.
At least, I can be confident that each image
I get is low noise, highly detailed, and
of the best quality.
If you only print 4x6 in. images, or display
small size for the Web, then the noise present
at high ISOs might not be too apparent at
these small sizes. Cameras in Category #2
may be more appropriate for you in this
Hopefully, the whole argument will soon
be moot because it is just a matter of time
(isn't it always) before we see compact
consumer digital cameras with both capabilities.
This will go a long way in allowing us to
take low noise, highly detailed, and high
quality indoors low-light shots without
the use of a tripod or flash.
High ISO is a scene mode that allows the
camera to select a fast enough shutter speed
- may eliminate, or reduce, the need for
image stabilization to counter camera
- may be fast enough to freeze action
and thus counter subject movement.
Most every digital camera today offers
the High ISO scene mode, so the presence
of High ISO in itself is not an advantage.
Furthermore, the use of high ISOs introduces
noise and image detail loss that are usually
unacceptable for advanced photographers
but may be unimportant to the average Point-and-Shoot
photographers. The only exception to this
are the Fujifilm digital cameras that are
equipped with the Super CCD HR image sensor
that has low-noise high-ISO characteristics.
Image Stabilization technology may be optical
or image sensor based, and counters the
effect of camera shake only. IS does not
mess with your exposure settings (again,
this may be more important to advanced than
The ideal digital camera is one that is
equipped with both IS and a low-noise high-ISO
Digital SLRs usually use a large image
sensor with low-noise high-ISO characteristics.
Some have an image sensor CCD-shift IS built
into the body that gives them the advantage
of having IS irrespective of the lens used;
others require you purchase IS-equipped
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