Olympus E-410 anti dust

The Olympus E-410, like all Four Thirds models so far, employs a SuperSonic Wave Filter to combat the problem of dust entering the body and casting annoying shadows onto the sensor. The SSWF system is widely regarded as one of the best in the industry, and in our tests it has certainly proven far more effective than rival systems.

The SSWF vibrates a special filter in front of the sensor in an attempt to shake-free any foreign particles which have entered the body. Unlike rival anti-dust systems though, the Four Thirds standard allows the vibrating filter to be positioned much further from the sensor itself. This helps a great deal, as any dust particles which remain are normally so far from the focal plane, they’re essentially rendered invisible at all but the smallest apertures.

When developing the E-400, Olympus had to design a brand new SSWF system to squeeze into the constraints of the smaller body. The filter also employed a higher frequency than earlier models, although Olympus wouldn’t disclose the details. In our E-400 review we put the new system to the test and were relieved to find it was as effective as previous E-Series DSLRs. While the E-410 shares the same SSWF system as its predecessor – and therefore should be equally effective – we’ve repeated our tests here to verify whether this is indeed the case.

At this point it’s important to note the evaluation of anti-dust dust systems can never be as controlled or consistent as other tests. After all, there’s no way of counting the number or type of dust particles which currently lie within a body, nor any way to introduce a consistent number of test particles for it to subsequently get rid of. As such it’s impossible to conclude one system is categorically better than another at eliminating dust.

Just because something can’t be scientifically measured though, doesn’t mean it should be glossed-over or ignored in a review. Dust is the number-one complaint for many DSLR owners and anti-dust systems have become some of the most talked-about and desirable features in new bodies. As such even anecdotal evidence is valuable and by gathering it from a number of sources over time we can build up a picture of how effective, or ineffective a system performs. That’s our belief at Camera Labs, so for the record here’s what we found.
 
First things first: like its predecessor, the E-410 performs the SSWF anti-dust process every time the camera’s switched on and there’s no way to override it. And like the E-400, there’s no animation advertising the SSWF to slow down the startup time – although if you do want to see it, just power-up without a memory card inserted. Under normal conditions, the only indication the cleaning process is taking place is a small blue light by the shutter release which flickers for just under a second during power-up.

Now to our anecdotal evidence. When examining our test shots with the E-410, there were no obvious dust marks, so like the E-400, we deliberately took much less care when changing lenses to see how the system would cope.

We removed the lens from the E-410 and left the body open and face-up indoors for five minutes. We then repeated this outdoors on a blustery day, again for five minutes. Again while there’s no way of knowing exactly how much dust got into the body, we’re pretty confident such activity would have resulted in many visible dust marks on other DSLRs.

The easiest way to spot dust marks is to manually focus the lens to infinity and shoot a plain white surface from about 30cm away. It’s revealing to try this at different apertures, as the bigger the f-number, the sharper and more defined any dust marks will become. So the ultimate torture test would be at, say, f22, although to be fair it’s important to also test at the more common apertures used day-to-day.

We photographed the white surface as described with each aperture setting, then opened the images in Photoshop and zoomed-in to 100% for close examination using a calibrated Eizo CG210 monitor. While our earlier E-400 results revealed no dust marks under these conditions, a couple of stubborn particles made it onto our E-410’s filter and refused to be shook free. These were however only visible at much smaller apertures, and even then, only faintly.

Below left you can see a 100% crop showing the dust mark, faintly visible in the middle; to make it more obvious we severely compressed the Levels in Photoshop to produce the result you see below right.

Olympus E-410 dust example at f22
100% crop measuring 282x212 pixels		100% crop measuring 282x212 pixels with Levels

We noted the exact position of the mark on the f22 image then looked for it in the other images. We’ve reproduced the same section of the image, taken at f5.6 below left, and shown the same area with the levels compressed in Photoshop below right. Even with severely compressed levels though, the mark remained essentially invisible up to around f8-f11, where it only became barely visible as a large but very faint patch. Closing the aperture further saw the mark become smaller and better defined as expected.

Olympus E-410 dust example at f5.6
100% crop measuring 282x212 pixels		100% crop measuring 282x212 pixels with Levels

These tests confirm dust settling on the filter even after it had vibrated several times, but equally prove they’d essentially remain invisible on your photos unless shooting at the smallest apertures.

So while not quite as impressive as our results from the E-400, it's still a great result for the SuperSonic Wave Filter - although its resistance to dust is as much to do with the distance between the filter and sensor as it is with the actual vibrating process itself. Either way, while the E-410 isn't totally immune to dust, it still does a better job than its rivals at getting rid of it, or at least making it hard to spot.