Image Stabilization in Olympus E-M1
Measured and Discussed
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The new Olympus wunderkind, the E-M1 is, indeed, a camera I like a lot — almost all of it. Like other Olympus μFT cameras (and FT ones before), it uses a body-based image stabilization system, compensating for the camera shake with small movements of the image sensor. We have seen this system work in the past, so it should work here just fine, too. No doubts about it.
In the promotional literature about this model, Olympus says it is "equipped with the world’s first 5-Axis image stabilization system with IS-Auto" which "compensates for vertical, horizontal and rotational camera shake that conventional 2-axis systems could not". Hey, not bad! We beat the competition by 150% in number of dimensions — this system must be better than others (including those we had in our older cameras).
Let me digress a bit more: the promotional passage was composed so that you cannot tell if  this is the first 5-axis system and it also has IS-Auto (whatever that is, probably a proprietary name), or  it is the first system having both a 5-Axis design and IS-Auto. Clearly, the follow-up suggests , but the company may say they meant just . Go figure.
Back in 2007 I developed a statistically and numerically sound procedure for defining and measuring the benefits of image stabilization in cameras. Indeed, having worked in areas of numerical and statistical analysis for forty years, I felt qualified for that. The procedure retains one of the most unreliable elements of the process: the human behind the camera, but I tried to minimize the impact of that, and the results turned out quite reproducible.
The procedure — briefly
Before we get to the results, I owe you some information about what they mean, lest we go the "four legs good, two legs bad" way (very much like most of the Web nowadays).
Briefly and roughly, the procedure (at a given, fixed focal length) involves shooting a number of frames (here: 20) at every whole-stop shutter speed in a wide interval, and then anonymous image evaluation to count the number of "good" frames at each speed. Finally, a numerical algorithm is used to determine the values of two parameters:
50 mm (12-50/3.5-6.3)
The effect of image stabilization is
After going through all this data, I can say the following:
Note of 2017: A dramatic change was, however, introduced by the recent IS lenses, as shown in our 100 mm case. Looks like this dual-IS system works very nicely with the E-M1 (updated firmware?), expanding handheld exposure range by (close to) 2 EV, close to the results on the E-M1 Mk.II.
Last but not least, remember that each EV in usable ISO settings replaces one EV in AF effectiveness. With at least two EV gained in ISO since the last E-series SLRs, we already experience an effect equivalent to 2 extra EV in image stabilization. While the hard-tech market, driven by specs and marketing blurb, may be hard to convince, I still think that image stabilization in still photography may be a transitional technology, going soon the way of the dodo.
The values of v0 and v100, and v50 are as described above and, in more detail, in the separate article on the method I'm using. The improvement (IS versus no IS) in v100 or in v50, which can be used to describe the benefits of image stabilization is shown in the last two columns.
Updated 2017/02/28: added data for 100 mm, obtained with the MZD 12-100 IS PRO lens — for comparison with the Mark II results.
|IS OFF||IS ON||Δv100||Δv50|
Note: The 100 mm, IS ON value of v100=1.455 is a bit surprising, bring better than 2.062 reported for the
This cannot be helped; the only way would be decreasing the spacing between tested shutter speeds to 1/3 EV; this, however, would be quite prohibitive.
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|Posted 2013/12/15; last updated 2017/02/27||Copyright © 2013-2017 by J. Andrzej Wrotniak|