How Important Is Image Stabilisation in Street Photography?

Most photographers pride themselves on their ability to hold the camera steady. It’s a prerequisite of the job, just like getting the subject in focus and using a suitable exposure time.

However, the shooting style of the street photographer is very different from those of the portrait, landscape, fashion, sports or travel photographer. Sometimes you need to get a shot “on the hoof” because stopping would attract the attention of the subject and ruin the composition.

Even using a wide angle lens and making a perilous semi-pause to minimise the movement of the camera, I find it all too easy to blur the image in normal light. Whereas, on an intensely sunny day I can set the shutter speed to 1/1,000th sec., I have to work at slower speeds in overcast conditions. Failure to do so reduces the depth of field. All those trade-offs! They’re the bane of photography, even though figuring them out successfully can be a joy.

Image stabilisation made its first appearance in 1995 and found a ready market in camcorders where it was needed most. From the start it was a hugely promising technology, solving the problem of camera movement by providing an opposing movement inside the lens. It smoothed out the jerkiness from one frame to the next, even though it didn’t quite get rid of all the micro-movements which plague the stills photographer.

Putting image stabilisation (IS) into the lenses of stills cameras became high priority at Canon, where the development team produced a special IS lens module controlled by an on-board microcomputer that could be fitted to the longer, telephoto lenses.

Partially pressing the shutter button starts up two gyro sensors (one for yaw and one for pitch) which detect the speed and angle of camera movement. The on-board microcomputer analyses the data, calculates the degree of correction required, and sends a command to the lens group to make the opposing movement. The system repeats this entire sequence continuously, giving you constant protection against camera shake.

As you can guess, the IS module is quite large and there’s not much room for it on wide angle lenses. Users like street photographers had to wait for the technology to be developed further. Today, Canon offer IS on wide angle lenses, including the EF24mm f/2.8 IS USM; EF28mm f/2.8 IS USM; and the EF35mm f/2 IS USM.

There was another giant step taken when in-body image stabilisation came along. Today, many up-market cameras, like the Sony A7RII, have sensor-shift stabilisation which can be applied at any time, regardless of the lens being used. Sensor-shift IS has also become a “must have” feature on mobile phone cameras, where is relatively easy to implement on account of the tiny size of the sensor.

What’s the Difference?
Personally I find IS a real benefit when shooting with my Canon f/4 24-70 zoom. I don’t normally use this lens for street photography on account of its slowness, size and weight, but the quality is so good I can’t resist it for set-piece events (like parades and carnivals) where photography is expected.

My featured shot (above) was taken at f/16, 1/160th sec., ISO 800, and I was thankful for the IS which allowed me to work with a small aperture and fairly slow shutter speed. I needed all the depth of field I could muster as the subjects were standing at an angle to the camera.

The IS compensates very well for the slowness of the lens, although it brings its own kind of slowness to the job. IS is not instantaneous. The delay, after you press the shutter button, was once a full second but has now been reduced to around half a second. If a week is a long time in politics (as the saying goes), a half second is a long time in street photography. I hope this delay can be reduced further.

As regards it effectiveness, the official Canon documentation states: “Image stabilisation is effective with movement from 0.5Hz to 20Hz (1Hz is one movement cycle per second). This will cope not only with situations from simple camera shake (0.5Hz to 3Hz), but also the engine vibrations encountered when shooting from a moving vehicle or helicopter (10Hz to 20Hz).”

Manufacturers measure IS performance in “shutter steps” (the shutter equivalent of aperture stops). A typical 4-step gain means you can obtain the sharpness expected at 1/250th of a second (without IS) while using a shutter speed of 1/15th of a second (with IS). The three wide angle Canon lenses mentioned above all have a 4-step gain.

Canon no longer has a monopoly on IS as other manufacturers have recognised its importance and have developed their own versions. Nikon has installed it many lenses while others have concentrated on in-body stabilisation.

One of the most remarkable examples of in-body stabilisation can be found in the Olympus OM-D E-M1 Mark II. The 5-axis Olympus IS system enables you to take hand-held photographs with exposures as long as one or two seconds. When you switch the camera to video the results are even more spectacular. For example, it virtually eliminates the typical up-down camera movement caused when you walk. The IS is so efficient many viewers may think you were wearing a complete rig to achieve such a smooth effect.

Should you rush out to buy the E-M1 Mark II on account of its stunning image stabilisation? It depends how high you place IS in your list of priorities.

I think some form of IS is necessary if you have difficulty keeping the camera steady, otherwise you’re limited to shooting on bright days. It’s a boon if you have a shakey hand or if you want to take pictures without breaking stride.

Just remember: it only counteracts your own movements, not those of the subject!

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