Shutter Shock: My ep5 is bad. Would an em5 do better?

Started 10 months ago | Discussions thread
DonSC
Contributing MemberPosts: 975
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Too much religion not any science
In reply to Anders W, 10 months ago

Anders W wrote:

First, the E-P5 has a max flash-sync speed of 1/320. This in turn means that the slowest shutter speed at which the first and second curtain move simultaneously (for a fraction, not the whole, of the exposure time) is 1/400.

Second, the first curtain does not close the shutter after exposure. It opens it for exposure. The second curtain then closes it.

Third, the exposure is never finished when the first curtain comes to a halt, regardless of which shutter speed we are talking about. It is finished when the second curtain comes to a halt.

Fourth, your reasoning presumes that the blur is due solely to one specific step in the sequence of shutter action: that when the first curtain comes to a halt. I don't know that we know that. On the contrary, we have a fair amount of evidence suggesting that even shutter movements before the exposure begins, such as that of the first curtain closing the shutter to prepare the sensor for exposure, has an impact. If it didn't, the anti-shock delay would be of no help whatsoever since all it does is to introduce a delay between that first phase of shutter action (the shutter closing to prepare the sensor for exposure) and subsequent phases (those involving the actual exposure).

This doesn't follow at all from the Imaging Resource findings and in fact flatly contradicts them. Apart from the fact that you've mis-stated -- either intentionally or not -- the X-Sync speed of the E-P5 (it's 1/250 NOT 1/320, the latter higher number being due to the flash pulse not the curtain speed), a reference to the X-Sync speed is meaningless. Imaging Resource found the blur from speeds of 1/100 to 1/200. At all those speeds the blur was more pronounced at the top of the image than at the bottom. In fact the article says that IF the blur was uniform across the image this would be DEFINITIVE PROOF that the blurring was not related to the shutter. This makes sense because at all shutter speeds the bottom of the sensor will be exposed longer to any vibrations caused when the first curtain opens. The article provides:

Accordingly, if we saw equal blur at the top and bottom of the image within the critical shutter speed range, that meant we could safely discount it as user-caused blur, rather than anomalous blur caused by the shutter mechanism.

Given that the X-Sync speed of the EP-1 is 1/180, a speed which is more or less smack in the middle of the shutter speeds at which the blur was observed but well ABOVE most of them, the fact that the E-P5 has a slightly higher X-Sync speed would not affect the basic conclusions, which would be that blurring due to vibrations from the first curtain should be non-uniform and the non-uniform blurring should be evident at all speeds at which blurring occurs. Since the OP never saw anything but uniform blur, according to your own authority the odds of the blur being caused by the shutter mechanism is asymptotically approaching zero.

Most likely it's hand holding technique. Rather than post about it why not put the camera on a tripod and see what you get?

This advice is based on the same "logic" as that of the man who looked for his keys under a street light because it was too dark where he dropped them.

If you want to know how the camera behaves with regard to shutter shock when shooting hand-held you need to test hand-held. If you suspect that hand-holding technique makes a difference, the proper course of action is to test different hand-holding techniques rather than put the camera on a tripod. Putting the camera on a tripod rather than holding it in your hands changes the situation in a large number of potentially important ways and can in no way isolate the effect of the cause you suggest: the particular way the camera is held in your hands.

Whatever. Putting it on a tripod is the simplest way to eliminate hand shake. In fact that's why tripods were invented. But yes, we wouldn't want to eliminate hand shake as the source of the problem because that would might create cognitive dissonance in the minds of the shutter shock faithful. Better to whine about the pressing need for an electronic curtain (be careful what you ask for).

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