E-P5 and "shtter Shock"

Started Oct 6, 2013 | Discussions thread
Anders W
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Re: E-P5 and "shtter Shock"
In reply to Simon Cowell, Oct 10, 2013

Simon Cowell wrote:

Anders W wrote:

Simon Cowell wrote:

Anders W wrote:

OK. But even if the Panasonic OIS worked perfectly, that wouldn't help if the sensor moved uncontrollably. The OIS system doesn't expect and can't even know about any sensor movement. It assumes the sensor to stay perfectly put and if it doesn't, you'd see significant blur even if the OIS worked perfectly. Hence, the fact that the OIS on the 14-45 reduces the blur to a significant extent indicates that uncontrollable sensor movement (due to the magnets not being able to hold the sensor rigidly in place) is not a factor or at least not a major factor.

OK, I get it, this reasoning sounds plausible. But have you thought about the possibility that the shutter causes a shock to the whole body including the lens and this is what makes the OIS work?

Sure. That's exactly what I think happens.

The vibration/shock (call it any way you want) may cause proportionally more uncontrollable movement to the sensor if the IBIS is unable to rigidly stabilize the sensor. And this may explain why using an OIS lens may reduce the blur but not completely eliminate it. All hypothetical of course.

No that wouldn't explain it. This is exactly the scenario we've already talked about. The OIS accounts for the shock and provided that the sensor stays put, the image is fine. If the sensor wouldn't stay put, the result would be blurred even if OIS did the job right.

I think we say the same thing here.

Good.

Of course, the more samples the better, but since a digital camera is an electronic device (or micro-electro-mechanical one) don't you think the blur should be reproducible even after taking into account some error tolerances and copy-to-copy variations?

In hand-held shooting, absolutely not. In tripod-based shooting, the variation would be significantly smaller but still there to at least some extent.

Yes, no system can be absolutely perfect but when DPR is talking about 60% of shots being blurred this variation is too much IMO (even if this is for handheld shots). Of course we knew IBIS is not perfect anyway.

I was speaking about the extent to which the magnitude of the blur varies from one shot to another. You are speaking about the overall percentage of blurred shots. Two different things.

In the test of Falk Lumo that I linked to, there is virtually no blur at these shutter speeds when the camera is placed on a heavy tripod (see section 4.2, the one I already referred to). I don't have such a tripod to test with but get the same result when placing the camera on something still heavier and rigid: a concrete floor.

So what is left to explain?

Hmm, DPR though say that there was blur even when they used a tripod.

Note that I said "heavy tripod".

I think it would be good to have an explanation as to why shutter shock is proportionally higher for shots in this range of speeds (1/80-1/250s). Cameras are instruments that should work in predictable ways and the average user would like to know why the variation of blurred shots may be higher for this speed range rather than, say, for the range 1/20-1/60s (or you think this is not the case?).

The peak tends to be about 1/125 and the problem declines gradually on either side of this peak. The reason there is gradually less blur at shutter speeds lower than 1/125 is that the short-lived shock affects a gradually smaller proportion of the total exposure time. The reason there is gradually less blur at shutter speeds higher than 1/125 is that the exposure will cover a gradually smaller proportion of the total camera movement due to the shock.

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