Image stabilization

Sony A900, Sony 70-200/2.8&160mm. A-1/13sec, shutter speed is really slow in order to achieve the effect of having a combination of moving and still objects. Even with a focal length of 160mm, you can see image stabilisation in action – the still face of the ballerina on the right is sharply defined.

Ever since the beginning of the 20th century film sensitivity has been on the increase. When the first compact cameras Leica appeared, equipped with sensitive black and white film, they became the favourite ‘weapon’ of choice of wartime reporters during the Second World War. Colour films had already been invented but they were still not in wide use, again because of their low sensitivity.

When single-lens reflex cameras appeared with their specially designed powerful telephoto lenses, photographers were faced with a new problem. In many cases light conditions allowed for shooting at speeds within the 1/100 – 1/200sec range. At such speeds, one could take a sharp image without the object having to stand still and pose for the camera, but if you are shooting with a telephoto lens, often the photo ends up being blurred because of an involuntary shake of the photographer’s hand. The viewing angle of telephoto lenses is much smaller and even the slightest shift in angle because the photographer moved is enough to cause a significant shift in the image. There is an unwritten rule, which is applicable only for photography with 24x36mm frames, which is that the denominator of the shutter speed equation must be equal to or greater than the focal length of the lens if we want to have some guarantee that the photo will not end up blurred. To apply this ratio to larger or smaller format we need to look at their 24×36 format equivalents. This is so because in reality the required shutter speed does not depend only on the focal length of the lens itself, but also on its angle range, which is different for the different frame formats. For example, when the frame is 24x36mm, a 50mm lens is normal (its focal length is equal to the diagonal of that frame) but when the format is 6x9mm, the same lens will already be considered wide-angle (with very big angle view), i.e. If we use a telephoto lens with a focal length of 400mm for a 35mm film, shutter speeds must be at least 1/400sec when we shoot with the camera in hand and not on a tripod. Of course, this is a rather relative rule which depends on how stable the hand of the photographer is.

The problem with blurred photos due to the wrong shutter speed is conventionally solved with the use of a tripod, a monopod or simply by propping the camera steadily in another way. Of course, the use of a tripod is related to additional inconveniences, caused by its weight, bulk and slow manipulation.

With the advances in electronic technology at the end of the 20th century we also saw the emergence of the first optical stabilisation systems which in many respects provided a solution to the problem of camera stability when shooting at low speeds or using a telephoto lens. The optical stabilisation system is based on a floating optical element controlled by a sophisticated system of sensors which register vibrations and micro motors shifting the optical element in accordance with the signals submitted by the sensors in order to compensate for the shakes of the photographer’s hand. The pioneers who introduced that system were Panasonic for their video cameras and Nikon for their cameras. In 1993 Nikon launched on the market their first compact camera with the VR sign (vibration reduction). Two years later the Japanese giant Canon created a similar system called IS (image stabilizer) for zoom lens 75-300mm designed for single-lens reflex cameras Canon EOS. With the popularisation of digital photography many companies developed their own optical stabilisation systems. It turned out that it was especially necessary for compact digital cameras with telephoto lenses whose small sensors were still not sensitive enough and rarely allowed for quality images above 100-200 ISO. In addition to the popular and well known VR by Nikon and IS by Canon, own systems and signs were also introduced by the brands Panasonic – OIS (optical image stabilizer), Sigma – OS (optical stabilizer), Konica-Minolta – AS (AntiShake), Sony – SSS (Super Steady Shot), Olympus, etc.

Sensor stabilisation by Sony
Double stabilisation of lens and sensor for Panasonic – Lumix
Double stabilisation of lens and sensor for Olympus

How important is optical stabilisation?

First of all, it is worth noting that optical stabilisation is not a 100% guarantee for a good image. It helps a lot, but it cannot replace a tripod for night photography with long exposure times, nor does it compensate for extensive shaking of the photographer’s hand. It is also important to know that this system compensates only for camera vibrations, so even at low shutter speeds static object will be sharp without any blurring, but they are not a replacement for high shutter speeds when it comes to freezing the movement of the object… Generally speaking, the optical stabilisation system gives you the opportunity to shoot at shutter speeds which are 8 times lower than normal (or 3 points lower exposure). Thus, if you use a lens with a focal length of 400mm, normal speeds should be 1/400sec. When the stabilisation system is on, this speed can be reduced to approximately 1/50sec, which allows us to achieve good quality photos with a telephoto lens even under unfavourable light conditions. The optical stabilisation system, however, helps to achieve sharper images even under good light conditions and small focal lengths, when we would think that the shutter speed is high enough to prevent image blurring. The shake of the photographer’s hand affects the quality of the image no matter the shutter speed and stabilisation neutralises and minimises these negative effects.

The following two portraits were taken at very poor light on the street at night with a 135mm lens. The inbuilt stabilisation system in the body of the camera is especially helpful in such situations. At speeds of 1/100sec without stabilisation nearly 50% of the photos will be blurred. The success rate for this photo shoot was over 90%.

Sony A99, Carl Zeiss 135/1.8, S-1/100sec, F-1.8, 6400ISO
Sony A99, Carl Zeiss 135/1.8, S-1/100sec, F-1.8, 6400ISO

Cameras with optical stabilisation give us the opportunity to achieve some interesting effects.

One such effect is panning at low shutter speeds while image stabilisation works only along the vertical axis. With this technique the object remains sharp while the background is blurred in the direction of the motion. Stabilisation is invaluable when shooting with a flash and we want to keep the effect of the present ambient light. In this case the main object is illuminated by the flash while the background retains its natural light and remains sharp. Another interesting effect can be produced when we shoot a moving object at low shutter speeds. This creates impressive artistic photographs where moving objects leave trails of their movement on a still background.

Sony A7Riii, Sony 24-70/2.8 S-1/3sec, F2.8, 200ISO . Even at shutter speeds as slow as 1/3 sec stabilisation can do an effective job. The relatively still audience is sharply defined while the fire dancers are drawing interesting figures in the air.
Sony 900, Carl Zeiss 24-70/2.8, S-1/15sec. F-2.8. Water sprays also leave traces at such shutter speeds.
Sony a99mk2, Carl Zeiss 24-70/2.8, S-1/13sec. F-2.8 A combination of still and moving objects.
Sony a99mk2, Carl Zeiss 24-70/2.8, S-1sec. F-2.8 .Evet with exposure times of 1 sec we can produce some good results.
Sony A7Riii, Sony 24-70/2.8G, S-1/10sec, F-4

And so, should we absolutely at any cost look for models with optical stabilisation when buying a new camera?

Some will probably respond negatively, but I will take the liberty to quote a famous stuffed fictional character and his legendary phrase ‘the more, the more’, which I believe nicely sums up my answer to this question.