Final word on OMD + PL 25mm "Rattlesnake"?

Started Apr 27, 2012 | Discussions thread
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Travis Veteran Member • Posts: 3,188
Final word on OMD + PL 25mm "Rattlesnake"?

I performed a search and read through some of the other comments regarding this issue, but I have not been able to reach a firm consensus on this issue. I'm specifically referring to the Panasonic-Leica 25mm F1.4 lens used in conjunction with the Olympus OM-D E-M5 digital camera.


A fairly loud clicking "rattlesnake" noise can be heard coming from the lens when used on the Olympus body. It does not negatively affect still image quality or performance, but I do believe it may be affecting video performance. Specifically, when I shoot video with the 25mm on my OMD, I get a "flickering" phenomenon that may or may not be related to the noise.

Here's a Youtube video (not mine) that clearly demonstrates the sound that is heard. Take note that no press of the shutter is needed for the lens to make this sound; it can clearly be heard simply by moving the camera around. Indeed, I initially thought that it was the Olympus IBIS making the noise when I first put the lens on my camera. But you can clearly hear it coming from the lens itself.

And since the lens has no IS itself, one can suspect that it's either 1) the sound of the aperture changing or 2) the focusing system. Since the issue happens even when the shutter is not being pressed (and no focusing is being done), it might be logical to suspect that it's the aperture changing as the camera communicates with the lens to determine exposure. This would also explain the "flickering" I'm seeing when shooting video because the aperture changes would reflect a change in brightness of the recorded video.

However, the phenomenon can occur even if I change to Video mode on the camera and use M-Manual mode. If I set my own aperture and shutter speed, I can still get the sound and flickering. However, sometimes the lens doesn't click at all and sometimes it clicks over half of the time I'm using it. I can not at this time determine a pattern, nor can I find a repeatable test to differentiate when it does it and when it does not.

I'm no technician so I don't know how the lens physically changes aperture and obtains focus. But it sure seems like it does it sometimes when it is focusing and other times when it's changing aperture. During the actual video recording, I do not hear the sound but certainly see the flickering. When half-pressing the shutter to obtain focus, the noise is definitely noticeable most of the time.

So as you can tell, I'm really confused by this issue! So here's what I know for sure, followed by my questions:

  • I know that it doesn't affect still image quality. The photos turn out great and in perfect focus. Sometimes it does seem to affect focus speed, however. Not all the time, and the lens is generally fairly quick to focus. It also seems to do it more outdoors than indoors (probably because the aperture stays at F1.4 most of the time indoors?

  • I know that something is affecting video quality, causing a "flickering" effect, somewhat like I saw on my Panasonic bodies previously when the aperture changed during recording (which was improved by the stepless aperture feature of lenses like the 14-140). However, it's really pronounced on this lens and body combination under certain circumstances (particular when moving around while recording video).

Here are my questions:

1) Can someone plain explain what this issue is and what causes it? Why does it happen on Oly bodies but not Panasonic? A communication problem between the camera and lens?

2) Why are some users reporting NO rattlesnake sound with this combination while others ARE? Has there been a firmware update to the lens? Would the Oly OMD firmware update (1.1) address this issue (I'm still on 1.0).

3) Are Panasonic and/or Olympus aware of the issue and promising a fix? Do we have a time estimate?

I am greatly enjoying the camera, and I was hoping this lens would be the one I used most (I love fast primes and 25mm is just the right FL for most of what I do). And while the rattlesnake is annoying when using it for stills, it's almost a deal-breaker for me with video unless I'm just shooting a steady scene with little to no focus/exposure changes.

Thanks for the input, suggestions, and explanations. Please educate me!


 Travis's gear list:Travis's gear list
Panasonic Lumix DMC-LX7 Panasonic LX100 Canon EOS 550D Panasonic Lumix DMC-GH3 Canon EF-S 15-85mm f/3.5-5.6 IS USM +4 more
Olympus OM-D E-M5
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