Why is there so much shutter noise with all 4/3s?

Started Sep 8, 2009 | Discussions thread
kenw
kenw Veteran Member • Posts: 5,347
Re: Why is there so much shutter noise with all 4/3s?

With an integrated lens camera (like a compact or a super-zoom) the "shutter" is typically part of the lens itself, most often being the same iris that sets the aperture. Since it is typically placed near the node of the lens it can be very small and thus move quite fast with little noise. There are downsides to this approach, especially in large aperture long focal length lenses (you can't open and closes the iris fast enough), but in the compact formats it is less of a problem and is thus a pretty good solution.

With interchangeable lens cameras there is no desire to have to put a very fast moving iris mechanism in every lens - if we did this the fastest shutter speed available would depend on what lens you were using and the lens would cost more money because of the requirement for a fancy iris. In addition most interchangeable lens cameras have large imagers and thus longer focal lengths and the in lens solution starts to show some warts - namely it becomes difficult to achieve very fast shutter speeds. Instead the shutter, in this case called a "focal plane shutter" since it exists near the focus of the lens rather than in the center of the lens, is right in front of the imager and needs to be the same size as the imager. The upside is that you only buy the shutter once with the camera and not with every lens. The down side is that the shutter being bigger has to move faster and has more mass and thus a lot more noise. Another upside is that you can reach almost arbitrarily fast shutter speeds like 1/8000 by having the shutter actually only expose a small slit that drops across the imager while the shutter itself moves at a more reasonable speed.

There is a final though not often used option - electronic shutters. The idea here is to use the imager to define the exposure instead of an external shutter. This is rarely done as it requires more electronics on the sensor which will cause more noise and less sensitivity. Such an approach would give you perfect quiet though. Some imagers take a halfway approach and provide a electronic reset - this allows a live view camera to leave the shutter open and start the exposure with an electronic reset of the imager and then end the exposure by closing the shutter while the data is read out of the imager.

Probably more than you wanted to know - short answer is that small compact cameras use small imagers that allow them to effectively put a tiny shutter inside the lens which is very quiet. Larger cameras with interchangeable lenses are more likely to put a larger shutter right in front of the imager separate from the lens and this will be louder on account of its bigger size and mass...

At least with micro four thirds there isn't a loud mirror slap on top of it...
--
Ken W

Rebel XT, XTi, Pany LX-3, FZ-28, Fuji F30, and a lot of 35mm and 4x5 sitting in the closet...

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