Image stabilization is a great thing to have in a camera. It might even make you choose a camera with in-body-stabilization over one that doesn’t have it, even if the rest of the specs aren’t as good. Nobody likes camera shake, right? But image stabilization, whether its in-camera IBIS or lens IS, isn’t always the life-saver it seems.
Why?
1. You don’t get the stabilization they quote
Image stabilization effectiveness is quoted in EV, or f-stops. It’s meant as a guide to how much you can slow down the shutter speed without getting camera shake. So for example, one camera might have an IBIS system rated at 8EV, another might have IBIS rated at 6.5EV and so on. But will you ever achieve this figures? I never have, and I have tested a lot of cameras and lenses.
What you have to remember is that although these cameras are tested by the independent testing body CIPA, the test must be standardized in order to have any scientific accuracy at all, and you can assume the camera makers know exactly what the test involves and perhaps how to engineer their IBIS systems to do well in it.
The other thing you will notice is that the claimed figures are for very specific camera body and lens combinations and not a guarantee for all the cameras and lenses you might use. It would make sense for camera makers to put forward the gear that’s going to give the best test results.
Lastly, makers will quote shake compensation of up to xEV. Now to my cynical mind, the phrase ‘up to’ means the same as ‘less than’ in the world of marketing.
As a rule, I expect to get around half the claimed stabilization figures from the equipment I test in practical shooting scenarios. I find some brands better (OM System, Panasonic) and some extremely variable (Canon).
2. It’s not like using a gimbal
You will sometimes see IBIS systems being praised for having gimbal-like stabilization. No. Gimbals are an entirely different device working on entirely different principles. Stabilization systems are designed to compensate for unintentional camera movement and work very rapidly with tiny adjustments to the sensor position or lens elements. Gimbals are designed to smooth out long and deliberate camera movements so that they are progressive and controlled. It’s a different thing. IBIS systems do not have the range of movement needed for this. Indeed, if you try a panning shot with IBIS enabled you might find it worse than not having IBIS at all, with a series of small but distracting jump-corrections as the IBIS tries to fix the moment, then has to recenter and try again.
IBIS is only ‘gimbal-like’ when you’re filming with the camera stationary. In these conditions, the best IBIS systems can be spectacularly good. Just don’t try any camera moves.
3. You don’t always need it
Camera shake happens when the camera moves during the exposure. The longer the focal length you use, the larger the magnification and the more any unintentional movement shows up. This is why the minimum ‘safe’ shutter speed is higher for telephoto lenses.
So the faster the shutter speed, the less risk there is of camera shake. We all vary in our ability to hold a camera perfectly still. Some photographers are uncannily good, I’m terrible. This is why it’s hard to be exact about ‘safe’ shutter speeds.
In any event, all an IBIS system does is extend the range of shutter speeds so that there’s less risk of shake when they become marginal. But every often, especially in outdoor photography, you’re working nowhere near these marginal shutter speeds anyway. For myself, I would start to worry about using shutter speeds slower than, say, 1/125sec without IBIS or lens IS, but with modern cameras and base ISOs typically around ISO 200, and modern lenses that tend to be sharp wide open anyway, I don’t often find myself down at these shutter speeds anyway.
IBIS is great in low light or interiors, but then so is increasing the ISO – and modern cameras are great at high ISOs too. It’s all about the shutter speed. IBIS lets you use slower shutter speeds, while ISO lets you use faster shutter speeds. Which leads on to perhaps the most important point of all…
4. Stabilizers stop camera movement, not subject movement
Faster shutter speeds don’t just reduce camera shake – they also reduce subject movement. So let’s say you’re photographing an indoor basketball event under artificial lighting. Your problem here is controlling subject movement and blur, and the only way to do that is with a fast enough shutter speed. Image stabilization won’t help you at all. This applies in any photography scenario where controlling subject movement is important.
You could say that faster shutter speeds solve two problems, both camera movement and subject movement, but stabilization solves only one.
5. Photography and video don’t need the same things
In stills photography, IBIS and lens IS are very useful because they can counteract the short, rapid movements that cause camera shake.
In video, camera shake is not a problem in the same way because you are filming a series of frames to be viewed in quick succession and you can expect there to be a certain amount of natural movement in each. In fact, it’s this movement that can help video look smooth and natural.
The bigger issue with video is movement between frames, which does make footage look shaky – but physical IBIS and lens IS systems are not necessarily well adapted for these longer, slower movements. This is where digital stabilization comes in.
Digital IS has no relevance for stills photography, but in video it can be an important tool for smoothing out camera movements. It works by constantly adjusting the framing of the shot so that the subject isn’t jerking around uncontrollably. It does mean the video is cropped, because digital IS does need the extra space around the frame for this constant reframing, but it is very effective. You can also apply this digital stabilization very successful in video editors.
So for video, physical IBIS or lens IS will help a lot with static shots, but for deliberate camera movements, digital IS might actually be a lot better.
For stills photography I would prefer a camera to have IBIS, but I wouldn’t make it a deal-breaker. For video, I would keep an open mind. IBIS does help, but digital IS is very effective too, though for any filming with planned camera movements, a gimbal will be smoothest of all.
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