In the overall history of camera technology image stabilization is a rather recent development. Image stabilized lenses did not appear up until 1995 when Canon introduced the EF 75-300mm f/4 – 5.6 IS – the first image stabilized lens. IS or Image Stabilization is the acronym that Canon uses to refer to this technology. The technology was actually first seen on a previous lens, also made by Canon, the EF 300mm f/2.8L IS USM. This lens however did not reach the market up until 1999 which made the 75-300mm the first commercially produced image stabilized lens the world has seen.
Nikon calls this technology VR or Vibration Reduction. Other manufacturers use different other acronyms to label this technology. However, at the end of the day, they all mean the exact same thing. Though, in this case it is fair to say that all technologies are not the same. In fact all lenses are not optically stabilized either. There are some manufacturers who prefer to stabilize the sensor inside the camera rather than the lens! Canon and Nikon, however, deduced that it was much easier to move the focusing elements inside the lens than moving the actual film.
Okay. Now we need to have a deeper understanding of how image stabilization works and why most professionals and serious enthusiasts prefer to pay more for image stabilized lenses.
You are photographing your kids playing in the yard along with the family pet. They are running around and are generally having a great time. You set your aperture to f/5.6, your focal length to 200mm and shutter speed to 1/100th of a second and fire away. After a few minutes you see that the images are not sharp. In fact most of them are blurry.
You are photographing the annual sports meet at the school. Your son is in the fray for the 100 meters sprint. The race starts. You pan your camera while firing away at 3-4 frames per second. After the race is over you review the images and notice that none of them are sharp. In fact all of them are moderate to extremely blurry.
The subject is walking towards you while you have AF on with your camera on a tripod. You fire away at several frames per second. Later on, while reviewing the images, you notice that most of them did not have the subject in sharp focus.
In all of the above scenarios (barring the third one, where improper AF selection could also have contributed to the blurry results) image stabilization would have helped the photographer to avoid image blur. Image stabilization is a technology that uses gyros and sensors built into the body of the lens, or in some cases inside the camera, to bring the image back on to the image plane after it has drifted away from it, either due to hand movements or due to any other reasons.
Types of Image Stabilization Systems
There are four types of image stabilization systems currently available in the market. Canon produced the first ever commercially made lens that had optical image stabilization. Their lenses feature all these four types including hybrid image stabilization. Other makes also have their own varieties of image stabilization systems which are similar.
Image Stabilization – Type 1
The first image stabilized lens only compensated for unintentional hand movements. It worked like this. Let’s say you are shooting a flower from a distance of 50 meters. You are using a focal length of 200mm. Your hands are shaking and the fact that you are using a longer focal length, the problem is getting compounded. In this case image stabilization will engage when you half-press the shutter button. Focus will be acquired. Now, if your hands move, the image stabilization system will kick-in. The gyros and sensors inside will sense that the camera is moving and will move the focusing elements in the opposite direction to bring the image back on to the image plane (sensor). Some cameras also have a focus lock button. It give you some additional leverage by allowing you to take your finger off the shutter release (while having a finger firmly placed on the focus lock button) and still have focus lock.
Image Stabilization – Type 2
In scenario 2 above we had discussed about a race where you pan while shooting. This is a classic case where the traditional image stabilization systems can get it all wrong. Lens with traditional image stabilization will try to stabilize the panning movement. In this case you want the subject of focus to be sharp whereas the rest of the frame can be out of focus. This is facilitated by the second version of image stabilization. In this, when the camera moves in a horizontal direction for a while, the lens will disengage image stabilization for that movement. However, it will engage image stabilization for any movements that are vertical to the said horizontal, or in this case, panning movement.
Image Stabilization – Type 3
Sometimes, even with image stabilization version 2 it still remains difficult for photographers to pan properly. As soon as any vertical movements (one to the direction of panning) are detected, the lens’s image stabilization kicks-in. Some professional photographers prefer to have image stabilization stay quiet until they have actually pressed the shutter release all the way. This is ideal when one needs absolutely smooth panning.
Hybrid Image Stabilization
This type of image stabilization utilizes a different technology which compensates for any movement that are parallel to the image plane. Traditional image stabilization, we discussed above, actually compensates for movements that are at an angle to the camera.
Some Bonus Tips on Using Image Stabilization
Your hands could move for a number of reasons, strong breeze, unstable platform etc. Some photographers have less steady hands than others. The lens will stabilize in all such conditions. A small tip – just in case you are reading this and don’t have a lens with image stabilization. You should never set your shutter speed to anything less than inverse of the focal length. Let’s take the example of the above paragraph yet again. Say, the focal length at which you are shooting at is 200mm. The camera is set to aperture priority and it meters the scene at 1/120th of a second (you have set the aperture at f/5.6). In this situation, invariably, there would be image shake. Now, some people have steadier hands than others, but usually if the shutter speed is less than inverse of the focal length it would be impossible to hand hold the camera and get a blur-free image. If you don’t have image stabilization and is hand-holding the camera, the best solution is to shoot at a shutter speed that is more than the inverse of the shutter speed. In the above case a shutter speed of 1/120th of second or faster would be ideal to avoid image blur.
You need to turn off image stabilization when you are using a tripod to shoot pictures. Tripods were the original tool of choice to stabilize the camera when built-in image stabilization was not around. Most nature photographers made it a point to lug a tripod at all times. A lot of them still do. However, with image stabilization, it is now possible to use shutter speeds up to 2 to 4 times slower while hand-holding the camera, making the tripod somewhat redundant. If for any reason you want to use a tripod, make sure that image stabilization is turned off. Otherwise, it will ‘imagine’ that the camera is moving and try to stabilize that imaginary movement.
Using Higher ISO
If you are using a compact point and shoot camera or a lens without image stabilization or don’t have a tripod and generally have no way to stabilize the camera, you could try tweaking the ISO number to compensate. At higher ISO, the sensor’s sensitivity to light is enhanced. This has the same effect of using a faster aperture, which in turn allows for the use of a faster shutter speed. As you are aware, a faster shutter speed freezes movement and minimizes image blur. However, at higher ISO some amount of digital noise could be involved. In that case you could shoot in RAW and adjust the noise in post processing.