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Pany 25mm rattlesnake syndrome, explain please.

Discussion in 'Native Lenses' started by Dave in Wales, Apr 16, 2012.

  1. Dave in Wales

    Dave in Wales Mu-43 All-Pro

    Nov 5, 2011
    West Wales
    I've got one arriving tomorrow, a lens not a rattlesnake that is, I wondered what this noise was and what I should be ready for.....is it a fault with the lens or are they all like that.
  2. drewbot

    drewbot Mu-43 Top Veteran

    Oct 21, 2011
    Toronto, ON
    It's the body you use; not the lens. Oly bodies seem to rattlesnake it. Panny bodies do not.
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  3. Olympus bodies use precise control of the lens aperture to maintain a constant exposure preview. Panasonic bodies adjust the aperture in much larger steps when faced with variances in exposure and as a result don't always provide a true representation of the final exposure but do manage to avoid the persistent rattlesnake noise.

    The problem is a combination of Olympus' live view philosophy and a lens that has a very noisy aperture mechanism. Virtually every live view camera exhibits rattlesnaking to a degree but the Olympus body/PL25 lens combination is one of the most prominent examples. You might be interested to know that the more expensive Fuji X-Pro1 also exhibits noticeable rattlesnaking, so we're in good company.
  4. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    It doesn't happen on all m4/3 cameras. Like Drewbot wrote, it happens primarily when the PL25 is used on an Oly camera. Although some have reported it on Pany cameras. While others have reported that there is no rattle snaking on their Oly camera. The rattle snaking or chatter is the aperture blades opening and closing, because the camera is metering the scene to display the view on the LCD or EVF. It's an annoyance for me, but some folks aren't bothered by it.
  5. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    I'm not sure if "preview" is the correct term to describe what the Oly cameras are doing. I no longer have any Oly bodies (for now, but that'll change when I get the OMD). But if I recall correctly, the Oly camera is showing an optimally exposed image on the LCD (or EVF), as opposed to what the final exposure will be. If the camera was showing a true representation of the final exposure, it shouldn't be constantly opening and closing the aperture blades right?
  6. gsciorio

    gsciorio Mu-43 Top Veteran

    Dec 29, 2011
    Miami, FL
    So if the noise comes from metering I'm assuming that the camera is in autoexposure mode and thus would not happen in manual exposure correct?
  7. I can't recall having taken an image with an Oly and seeing the image playback look different to what I was seeing on the LCD or EVF prior to the shutter release. This has not been the case with both of the two Panasonics that I have used, which seem to operate on a near-enough-is-good-enough basis. I think that to provide a faithful representation of the final exposure the Olympus bodies need to exercise greater control over the amount of light hitting the sensor.

    I think that the Olympus philosophy is correct to make the most of having live-view available, but it does have consequences.
  8. I don't use M mode normally, but I just did a quick-and-dirty test with my E-PL1/20mm by moving it from a light to a dark scene and the rattlesnaking appeared to stop when switched to M mode. In P mode it was trying to adjust the screen exposure (as it should) everytime I moved the camera.
  9. krugorg

    krugorg Mu-43 Hall of Famer

    Jul 18, 2011
    Minnesota USA
    If you are using an Olympus E-P3, it may sound something like this:

    <iframe frameborder="0" scrolling="no" width="425" height="240" src="http://api.smugmug.com/services/embed/1502501653_967SNwP?width=425&height=240"></iframe>

    I could never figure out why (all settings seemed the same), but the PL25 did not do this on my E-P2. I know others with that body did report the problem, though. :confused: 

    What a great explanation! :bravo-009:
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  10. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    Nic, I'm just confused ... and perhaps because I'm trying to think things from a logical standpoint ... and sometimes there's no logic!! I am/was disappointed with Pany's rendition of the exposure preview as well (and white balance preview too) on the GF2 and GH2. But it just sounds logical that for a true exposure preview to occur, the aperture blades should not be opening and closing. Assuming that the user is using aperture priority, the aperture ought to stay at whatever the user set it on.

    Kyle, I had the rattle snaking on both the EP2 and EP3. On the EP3, the chatter lessened significantly on manual exposure mode. But it made no difference on the EP2. Figure ...
  11. Dave in Wales

    Dave in Wales Mu-43 All-Pro

    Nov 5, 2011
    West Wales
    That's a relief I use Pany bodies.
  12. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    I got the GF2 just because I wanted to avoid the rattlesnaking. Otherwise, I'd have kept the EP3.
  13. D@ne

    D@ne Mu-43 Top Veteran

    Feb 23, 2012
    My experiences - I can use my camera (epm1) with the 25 for a while before the sound begins...then it doesn't really go away...I never hear the noise for the first 10 minutes or so of using the camera.

    When the noise begins, it doesn't matter what mode i"m using...manual...A...P, etc. All make the noise.

    Once the noise does begin, if I turn the camera off and back on instantly, it will continue. If I turn it off for a few minutes, then turn it back on, it will be gone (for at least few minutes).

    I have no scientific explanation for any of this...only observances.
  14. iau

    iau Mu-43 Regular

    Dec 19, 2009
    I have it on the GX1 and the aperture rattles or clicks in bright light. Helps to stop down to about f8 sometimes. It's a little annoying but I've learned to ignore it.
  15. Armando, you may be getting confused with the depth-of-field preview. When I say exposure preview I am referring simply to the relative brightness of the live-view image compared to the image that is taken and displayed after releasing the shutter. I find that Olympus bodies provide an accurate preview all of the time, and Panasonic bodies most of the time.

    I have found that my E-P2 is better behaved than my E-PL1 but not perfect. On my GH1 you'll only hear the occasional single click compared to the rattle on the Olys.
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  16. David A

    David A Mu-43 All-Pro

    Sep 30, 2011
    Brisbane, Australia
    I haven't used a Panasonic M43 camera so I don't know what they do.

    On my E-P3 the brightness of the LCD/viewfinder image is maintained at a standard constant level unless I engage depth of field preview or exposure compensation in which case the brightness changes in accordance with that selection. Whether the lighting I'm working in is bright or dim, the image is set at a standard brightness level. From what I understand, that means that the camera stops the lens down a bit in brighter light and opens it up a bit in dimmer light to some degree, and that means the aperture blades are opening and closing at times other than when the image is being made.

    The camera responds automatically to changes in the level of light falling on the sensor while doing this, and that means that if the amount of light falling on the sensor changes by more than a set amount the aperture setting is changed. If you have noisy aperture blades you can hear this.

    For some reason with the PL25 the change in aperture when this occurs seems to take a bit of "hunting" to get right so you get the rattlesnake noise of the blades opening and closing a bit until the camera seems to get it right and the noise stops. That tends to take at most a few seconds on my E-P3 with the PL25 unless I keep moving the camera and changing the amount of light entering the lens. I can keep the noise going by continuing to change where I'm pointing the lens from somewhere dark to somewhere bright but if I simply point at one place and don't move the camera the noise settles within a few seconds. In addition the noise isn't loud with my camera and PL25 and can even be covered by background noise around me.

    If I have the camera turned on and the lens cap off, I get the noise occasionally as I move around because the lens is always pointed somewhere and if I'm moving, what the lens is pointing at is changing and that means that every now and then the amount of light falling on the sensor changes enough to trigger this process.

    And I get the noise when I've got the camera set to manual mode. I believe this occurs because the camera still maintains a constant image brightness on the screen/viewfinder. The image doesn't go darker if I set the aperture to f/16 and brighter if I set it to f/1.4 in manual mode, just as it doesn't in P, A or S modes, unless I engage depth of field preview or exposure compensation. That's why the noise still occurs in M mode—it's got nothing to do with the mode you're shooting in, it's related to the camera's behaviour in keeping your screen/viewfinder image at a constant brightness level.

    I first thought of getting the PL25 months ago and was put off by the reports of this noise which, based on my reading of various posts, I thought was both extremely loud and also constant in bright light. When I finally decided to try the lens on my camera in a shop, I discovered that the noise wasn't particularly loud at all, and almost impossible to hear when I walked outside the shop onto the footpath with people and light traffic noise around me, and that it also stopped after a few seconds unless I kept changing where I was pointing the camera. What I thought would be a definite no factor for me turned out not to be a problem for me. I bought the lens. I can only suggest to others that they try it on their Olympus body before making a decision because, like me, they may not find it the problem they think it is.

    Having said that there's a wide range of variation in the reports of the level of this noise and whether or not it occurs with certain Olympus bodies and I don't think all of that variation can be accounted for by differences in what different individuals believe is an acceptable noise level and what isn't. I wonder whether they may not be some variation in noise between different copies of this lens, and some variation in the behaviour of different Olympus camera models. I think it's possible that some people have cameras that may be more prone to this problem than others or exhibit the problem more severely than others. Once again that's an argument for trying the lens on your camera first, and even possibly trying a couple of different copies of the lens on your camera if you can.
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  17. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    I'm often confused! :smile: But on this particular topic, I am with you, and definitely not thinking about DOF preview. It seems that Oly and Fuji are using the aperture to control the amount of light irrespective of the aperture that the user may have set the camera at.

    David wrote it down much more eloquently than I could ever have!

  18. Lawrence A.

    Lawrence A. Mu-43 All-Pro

    Mar 14, 2012
    New Mexico
    But until the shutter is actually released for the exposure, the only variable the camera can work with for live view in any of the auto modes is the aperture, right. So the variable aperture as you view auto live view does not necessarily indicate the the taking aperture I assume. Having heard the video about, and being about to get a PL25mm, I'm glad I shoot manual most of the time. That would drive me crazy!
  19. dhazeghi

    dhazeghi Mu-43 Hall of Famer Subscribing Member

    Aug 6, 2010
    San Jose, CA
    Precisely. It's also not that hard to fix - they could simply apply digital gain to the image in cases where the fluctuations in light-level are small.

    The exposure mode is a red herring, unless it disables the EVF/LCD's auto-brightness.

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    • Agree Agree x 1
  20. rstrader

    rstrader Mu-43 Regular Subscribing Member

    Apr 12, 2012
    Colorado Springs
    I shoot mine in manual with studio strobes and never have any "rattlesnaking". I've never heard it rattlesnake outside either as I usually shoot in manual mode.
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