Optical image stabilization (OIS) is a very useful feature. It allows you to shoot handheld video without shaking, as well as take photos at long shutter speeds without blurring—for example, at night or in a dimly lit room. However, not all OIS is equally effective—some compensate for shake less effectively than others. But how do you measure OIS effectiveness?illustration by Samsung

This is precisely what the CIPA standard, developed by the Japanese Camera & Imaging Products Association, exists for. They have many standards, including one for screwdrivers, but we’re interested in CIPA DC-X011—a standard for measuring and describing the performance of optical image stabilization in digital cameras. It allows OIS effectiveness to be described in a single number: the higher, the better.

So, CIPA image stabilization isn’t some special technology. The standard doesn’t really care how the manufacturer achieves the required OIS quality. It’s simply a benchmark for OIS, and the more points a camera can achieve, the better. Honor, for example, scored six and a half points, and that seems to be a record for smartphones so far. That’s enough for a basic understanding, but let’s dig a little deeper and try to understand what these numbers actually mean.

How is CIPA calculated?

As I’ve already mentioned, OIS allows for handheld video shooting without shaking, as well as long-exposure photography without blur. The CIPA standard is entirely focused on the second scenario—after all, it was developed primarily for still cameras, not video cameras. In this case, OIS’s purpose is to allow longer shutter speeds and avoid blur. The measure of OIS’s effectiveness, then, is how many times longer shutter speeds it can compensate for.

This is exactly what the CIPA standard measures. The measurement procedure is rather complex, but I’ll explain it.One-picture testing procedure

The camera is placed on a shaking stand in front of a static image. First, the shutter speed is set to 1/eq s (e.g., 1/24 s for a smartphone’s main camera, 1/120 s for a 5x telephoto lens, and so on). Why this? For no reason at all, it’s not important right now. With the shaking stand turned off (i.e., without shaking), a dozen or more photos are taken, and the average blur level is measured. This creates a baseline for how blurry the camera takes photos when held on a tripod. This is necessary to account for other possible sources of blur.The red dot is the result of a shake-free blur measurement. The line is the baseline we’ll use for our calculations.

After this, they turn on the shaker, set a slow shutter speed, take a bunch of photos with OIS enabled, and calculate the average blur level. If the blur level is higher than without shake (which is likely to be the case), they reduce the shutter speed by half and take another bunch of photos. This continues until the average blur level is lower than the same baseline blur level without shake. This determines the maximum shutter speed at which the camera, even with shake, shoots as if it were on a tripod with OIS enabled.The green line is the result of measurements with OIS enabled.

Now, ideally, we should compare this result with how the camera shoots without OIS. Unfortunately, most optical stabilization systems are designed in such a way that it’s physically impossible to completely disable them. Therefore, instead of testing without OIS, the standard requires calculating blur levels without stabilization theoretically, using formulas. This determines the maximum shutter speed at which the camera shoots as if it were on a tripod, even with shake, when OIS is disabled.The blue line is the theoretical calculation for the OIS turned off.

Now, to evaluate the effectiveness of OIS, simply divide the maximum shutter speed with OIS by the maximum shutter speed without OIS. Let’s say we found that with OIS, a sharp image can be achieved at a maximum shutter speed of 1/4 s, while without OIS, calculations showed a maximum shutter speed of 1/115 s. The difference is 57.5 times. All that’s left is to take the base-2 logarithm of this number (5.85) and round down to the nearest halves (5.5). This gives us a CIPA stabilization rating of 5.5.The red band is how much you can extend your shutter speed without blurring the image, thanks to OIS. The longer it is, the more effective the OIS is!

Here’s a list of how many times longer the shutter speed each CIPA level extends:

  • CIPA 0.5 – from 1.4 to 2 times
  • CIPA 1.0 – from 2 to 2.8 times
  • CIPA 1.5 – from 2.8 to 4 times
  • CIPA 2.0 – from 4 to 5.6 times
  • CIPA 2.5 – from 5.6 to 8 times
  • CIPA 3.0 – from 8 to 11 times
  • CIPA 3.5 – from 11 to 16 times
  • CIPA 4.0 – from 16 to 23 times
  • CIPA 4.5 – from 23 to 32 times
  • CIPA 5.0 – from 32 to 45 times
  • CIPA 5.5 – from 45 to 64 times
  • CIPA 6.0 – from 64 to 90 times
  • CIPA 6.5 – from 90 to 128 times
  • CIPA 7.0 – from 128 to 181 times
  • CIPA 7.5 – from 181 to 256 times
  • CIPA 8.0 – from 256 to 362 times
  • and so on

The standard, of course, describes this entire procedure in much more detail than I’ve described. It describes precisely how to answer the question “how blurry are the photos a camera takes” (in microns!), what kind of shaker the camera should be, what vibrations it should generate, what the camera should capture, from what distance, how it should be mounted on the shaker, and so on. If you’re interested in all these nuances, you can read about them at the link . But I think these details will only be of interest to those who actually test cameras against the standard.

Conclusions

Although the CIPA test is very complex, I find it quite reasonable, and its extremely precise wording leaves no room for manufacturers to cheat during testing. So, if you’re concerned about the quality of optical image stabilization and want to take long-exposure photos or shoot handheld video, you can certainly use the CIPA numbers as a guide when choosing a smartphone. Hopefully, over time, more manufacturers will begin to include these numbers in the specifications, so buyers can use this parameter as a guide when choosing a smartphone. Until then, you’ll have to choose whatever’s on sale, right?