Beginner image stabilization

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S.F Simelane

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hello everyone am new here, i would like to know what is image stabilization and why is it important? thank you
 
Exactly what it says. The lens or camera in some cases stabilises motion in incurred from movement of the device.
It's done by moving the sensor or lens elements.

It's important as you can take photos handheld and much slower shutter speeds than without as your bodies movement is counteracted.

Of course it cannot affect the movement of the subject. You still need a fast enough shutter speed for that.
 
If you are holding the camera up to your eye (rather than using a tripod), the camera will naturally 'wobble' a bit (you can't hold it perfectly still).
The 'rule of thumb' is that this will be significant enough to make the image blurred if the shutter speed is in the region of 1/(lens focal length) or slower.
So if you are using a 50mm lens, you would want to have a shutter speed faster then 1/50th s (EG 1/100th second).
Image stabilisation detects the camera 'wobble', and reduces the blurring it causes, allowing you to have a longer shutter speed and still get a sharp image.
So for the 50mm lens, if you had image stabilisation you might be OK with a shutter speed of 1/20th second, for example.
As Tom mentions, this does NOT help with blur caused by objects in the scene moving. So you might get a nice sharp building at 1/20th, but if you also have someone walking past the building, they would be blurred due to the amount they physically move in that time.
 
I think it's easier to think of as a system that corrects for motion of the camera. Some systems do this by moving a group of elements in the lens, others move the sensor within the camera body & the best can use both systems together.
I don't think lens based stabilisation can correct for rotation around the lens axis, but it can usually manage to correct for more tilt in long lenses.
In body stabilisation can work with any lens that can be mounted on the camera, can in some designs correct for rotation around the lens axis, but doesn't stabilise the viewfinder of DSLRs (a significant drawback when using long lenses on my Pentaxes).
 
Faldrax said:
So for the 50mm lens, if you had image stabilisation you might be OK with a shutter speed of 1/20th second, for example.
As Tom mentions, this does NOT help with blur caused by objects in the scene moving. So you might get a nice sharp building at 1/20th, but if you also have someone walking past the building, they would be blurred due to the amount they physically move in that time.
Click to expand...
Most stabilisation systems will allow considerably more improvement than this 1/20s is only ~1 stop slower even back in 2006 when my K100d was released 2 to 3 stops slower was generally practical. Today's cameras often give more than 5 stops stabilisation - giving a reasonable chance of getting a sharp image with a half second exposure. Good technique has always allowed hand-holding successfully at speeds slightly below the rule of thumb combined with IS & a bit of luck can allow really impressive exposures, I think I've seen a few shots taken with exposures around 2 seconds.
 
Petrochemist said:
Most stabilisation systems will allow considerably more improvement than this 1/20s is only ~1 stop slower even back in 2006 when my K100d was released 2 to 3 stops slower was generally practical. Today's cameras often give more than 5 stops stabilisation - giving a reasonable chance of getting a sharp image with a half second exposure. Good technique has always allowed hand-holding successfully at speeds slightly below the rule of thumb combined with IS & a bit of luck can allow really impressive exposures, I think I've seen a few shots taken with exposures around 2 seconds.
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I'd agree - but I'd much rather under-estimate how slow a shutter an IS system might allow, particularly to a beginner who might not have the best technique for hand holding to begin with.
 
I think we are doing someone else’s homework :(
 
S.F Simelane said:
hello everyone am new here, i would like to know what is image stabilization and why is it important? thank you
Click to expand...


very simply :)

Application in still photography
In photography, image stabilization can facilitate shutter speeds 2 to 5.5 stops slower (exposures 4 to 22+1⁄2 times longer), and even slower effective speeds have been reported.

A rule of thumb to determine the slowest shutter speed possible for hand-holding without noticeable blur due to camera shake is to take the reciprocal of the 35 mm equivalent focal length of the lens, also known as the "1/mm rule"[a]. For example, at a focal length of 125 mm on a 35 mm camera, vibration or camera shake could affect sharpness if the shutter speed is slower than 1⁄125 second. As a result of the 2-to-4.5-stops slower shutter speeds allowed by IS, an image taken at 1⁄125 second speed with an ordinary lens could be taken at 1⁄15 or 1⁄8 second with an IS-equipped lens and produce almost the same quality. The sharpness obtainable at a given speed can increase dramatically.[3] When calculating the effective focal length, it is important to take into account the image format a camera uses. For example, many digital SLR cameras use an image sensor that is 2⁄3, 5⁄8, or 1⁄2 the size of a 35 mm film frame. This means that the 35 mm frame is 1.5, 1.6, or 2 times the size of the digital sensor. The latter values are referred to as the crop factor, field-of-view crop factor, focal-length multiplier, or format factor. On a 2× crop factor camera, for instance, a 50 mm lens produces the same field of view as a 100 mm lens used on a 35 mm film camera, and can typically be handheld at 1⁄100 second.

However, image stabilization does not prevent motion blur caused by the movement of the subject or by extreme movements of the camera. Image stabilization is only designed for and capable of reducing blur that results from normal, minute shaking of a lens due to hand-held shooting. Some lenses and camera bodies include a secondary panning mode or a more aggressive 'active mode', both described in greater detail below under optical image stabilization.

Astrophotography makes much use of long-exposure photography, which requires the camera to be fixed in place. However, fastening it to the Earth is not enough, since the Earth rotates. The Pentax K-5 and K-r, when equipped with the O-GPS1 GPS accessory for position data, can use their sensor-shift capability to reduce the resulting star trails.[4]

Stabilization can be applied in the lens, or in the camera body. Each method has distinctive advantages and disadvantages.

Hope this clears things up ???

Les :)
 
Hi @S.F Simelane - maybe I can offer you and all your friends who have signed up to this forum a little bit of advice...

if you sign up, and your first post is a single sentance question asking "what is...." - you're going to get a few of the members pushing back or saying "just do your own homework/google it".

However, if you go into the beginners forum, introduce yourself, give a quick "biography" or details of what you do, what you like shooting, what you feel you'd like to learn from being here, and how you think you could maybe help others on here" then you'll get a far more welcoming response.

If you then proceed to share some of your photo's in one of the photo sharing sections that'd be brilliant. Same thing if you apply your knowledge of photography to giving critique and feedback on other peoples images,

What I'm saying here, is that this is a community, not just a reference library staffed by people for your assitance. Join, participate, give something to the community, and it'll be reciprocated many, many times over.

Don't be offended if people post links to various websites in answer to a question, very often these posted links ARE the best resource that the person knows to explain it - it's a "curated" link if you will. I've posted many links to your college compatriots questions already - because, frankly, the best info I know was in them, and not only was I not going to plagiarise the other site, I wasn't about to re-type 5000+ words and source multiple photos and diagrams in illustration.

You may notice a marker against my name stating that I'm a Staff Member here. As such, what i've stated above would probably be a good thing to take on board, and to pass onto your friends who may also be posting on here - and perhaps also feed back to the lecturer who pointed you at this forum in the first place...

Enjoy your time within our community :)
 
S.F Simelane said:
hello everyone am new here, i would like to know what is image stabilization and why is it important? thank you
Click to expand...

Image stabilization is a feature that is found in some cameras and lenses. Its important because it helps avoid the blur of a camera shake.
 
S.F Simelane said:
hello everyone am new here, i would like to know what is image stabilization and why is it important? thank you
Click to expand...


You can use the Image Stabilisation option if you want to, to help take a steady looking photo.

But I would strongly suggest that you should still need to learn how to hold a camera correctly, practise holding it still, breath out and squeeze the shutter button. Practise, practise, practise.

Remember that the Image Stabilisation option, like any other piece of technology, can fail.
 
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