om-d sound even when IBIS off??

Started Apr 16, 2013 | Discussions thread
Anders W
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Re: om-d sound even when IBIS off??
In reply to Ron Outdoors, Apr 17, 2013

Ron Outdoors wrote:

Second, the motion sensors wouldn't have to work when IBIS is turned off. Yet, the noise is of equal strength regardless of whether IBIS is on or off.

On my OM-D there is a quite noticable difference in the sound level between the IS being turned on and turned off. I have no idea why you are hearing otherwise.

When do you hear this noticeable difference? When you half-press the shutter button in stills mode? If so, sure, because in that case IBIS will go into full power only if it is a) set to on and b) you have set the option to activate it by means of half-pressing the shutter button. If either condition is not met, it won't go into full power until you make the exposure.

Have you tried making long exposures (several seconds)? In this case, you will hear a clear noise from the IBIS system regardless of whether it is on or off.

When making these exposures, try first with the camera perfectly still during the exposure. In this case, the sound will be identical with IBIS on and off. Now try again but move the camera around quite a bit during the exposure, preferably with a reasonably long FL. In this case, the sound with IBIS off will be the same as before, but with IBIS on it will become more irregular since the electromagnets are no longer just keeping the sensor in place but move it around to compensate for your movement.

How do you know that it is gyros you are hearing in that case? I would rather think it is the mechanism moving the IS lens group.

The gyro sound with Canon lenses is there even if the lens/camera is held stable. The gyro spinning sound continues several seconds after the shutter is let go, when no lens correction movement would be taking place.

I don't claim to know exactly how the Canon system works because I haven't used it myself. Nor have I read a whole lot about it. How the Canon IS works, however, does not really tell us anything about the way the E-M5 IBIS works.

At any rate, how do you know that it is gyros you are hearing in the case of your Canon equipment? It might just as well be the mechanism holding the IS lens group in place. As soon as the IS lens group is unlocked, which may be what happens when you activate the system by half-pressing the shutter button, some force must keep it in place even if the camera isn't moving at all. The same is true about the sensor on the E-M5. Without power, the sensor isn't kept in place at the proper position. The "thunk" you hear when you turn off the camera or it goes into sleep mode is from the sensor falling down when the electromagnets lose power.

Note that the causes of the E-M5 IBIS noise were discussed in considerable detail on this forum about the time the E-M5 was released. Some people advanced your hypothesis already at that point but it was quickly shot down for the reasons spelled out above.

I had googled older posts. One of the big theories originally was fan noise.

If so, it would be a fan cooling the electromagnetic system. It is difficult to distinguish by means of testing between the electromagnetic system itself and any device used to cool it. Both may be presumed to go on and off at the same time.

I don't see where the gyro theory was disproved.

I gave you no less than four major points that disprove it. Did you miss all those? If not, how would you explain the observations I made at the beginning of my previous reply based on your gyro theory?

If it sounds like a gyro and acts like a gyro, I would suspect it's a gyro. Maybe someone will take the camera apart and prove otherwise.

It doesn't sound like a gyro (far too irregular when actively stabilizing the sensor). And, for the reasons listed in my previous post, it (the sound) doesn't act like a gyro either. So no reason to think it is caused by one.

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