Understanding 'rattlesnaking' and the EVF of the E-M1

Started Oct 26, 2013 | Discussions thread
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Danielvr Veteran Member • Posts: 3,188
Understanding 'rattlesnaking' and the EVF of the E-M1

Several users of the SHG Zuiko lenses are concerned that the aperture mechanism in their expensive lenses may wear out if they switch to the E-M1.

Apparently the E-M1 tries to keep the brightness of its electronic viewfinder constant by adjusting the aperture when the light in the scene changes. And so, under some circumstances, the diaphragm may open and close so often that an unnerving 'rattlesnaking' sound can be heard. Some post suggest that the problem won't present itself very frequently in real world shooting, but it's still a concern.

I'm opening this thread so we can investigate the problem and discuss possible workarounds and solutions. I have an E-M1 myself, but can't use it for now because I have yet to receive my 4/3 mount adapter. So, I hope other E-M1 users will be willing to help investigate and experiment so we get a better understanding of the problem. Here are a few opening thoughts:

• First of all, how about this EVF? I was always under the impression that EVFs offer a WYSIWYG presentation of the scene that you're shooting - in other words, I had assumed that the mirrorless camera would keep the aperture fixed at whatever value you'd set in order to show you the real depth of field (contrary to OVF where you look through a wide-open aperture). Apparently that isn't true, or maybe there are multiple modes of EVF operation. Could someone clear this up for me - and is this really the cause of the rapid aperture changes?

• Secondly, p.97 of the english E-M1 manual says: "Brightness is automatically adjusted when [EVF Auto Luminance] is set to [On]." Doesn't this suggest that one could end the rattlesnaking problem simply by disabling [EVF Auto Luminance] ?

• Thirdly, I can imagine that when the light in the scene is constantly changing precisely around a certain threshold (eg clouds passing by or tree branches moving in the wind), the camera may be adjusting the aperture all the time. But I think it could as well change the exposure (read out) time or the ISO to accomplish the same thing, and Oly could solve the problem in firmware simply by giving higher priority to these other adjustments, so the aperture is left alone.

In closing, please keep this thread productive and use it only to examine and explain the technical issue at hand - we already have several different threads running for those who prefer to just vent their frustration or mourn their $10K lens investment.

 Danielvr's gear list:Danielvr's gear list
Olympus E-330 Olympus E-510 Olympus E-M1 Olympus Zuiko Digital ED 12-60mm 1:2.8-4.0 SWD Olympus Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD +2 more
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