Personal View site logo
12-35mm F2.8 Panasonic lens topic
  • 492 Replies sorted by
  • LPowellLPowell

    I've observed aperture glitches in most of the Panasonic and Olympus zoom lenses I've tested. My conclusion is that none of these lenses are built with a mechanically constant aperture - they all use electronic iris control to simulate the aperture you select. This includes the following lenses:

    Olympus 35-100mm f2.0

    Olympus 14-54mm f2.8-3.5

    Olympus 9-18mm f4-5.6

    Panasonic 14-50mm f2.8-3.5

    Panasonic 14-45mm f3.5-5.6

    Panasonic 45mm-200mm f4-5.6

    Panasonic 14-140mm f4-5.8

    Panasonic 45-175mm f4-5.6

    What happens when you zoom is the camera detects the altered focal length and electronically adjusts the iris to dynamically maintain the aperture you've selected. But in practice, the iris is not stepless and occasionally clicks when adjusted. What's worse is that since the camera is unable to track continuous zooming in real time, dynamic iris adjustments often lag behind the zoom.

  • MikhailKMikhailK

    @Vitaliy_Kiselev, thanks for the advice. I'll do it.

  • Vitaliy_KiselevVitaliy_Kiselev

    sorry, I don't get your point. What do you mean?

    I mean - cover the lens contacts and film zooming in.

  • MikhailKMikhailK

    @Vitaliy_Kiselev sorry, I don't get your point. What do you mean? Anyway, is my opinion correct that this is a "fake" constant f/2.8 lens?

  • Vitaliy_KiselevVitaliy_Kiselev

    Does it really mean it's a fake constant f/2.8 lens?

    You can cover the contacts and check :-)

  • MikhailKMikhailK

    @Vitaliy_Kiselev, would you be so kind to comment your thoughts on the thing I sad:

    "Yesterday I looked at the front mount of my lens and noticed the following. I set f/2.8 and started zooming in. The more I zoom in, the more the aperture squeezes".

    Does it really mean it's a fake constant f/2.8 lens?

  • nomadnomad

    Maybe sample variation? I was just commenting on divergent commentaries here, I didn't test it myself (yet).

  • MikhailKMikhailK

    @nomad I didn't get it - if your comment relates to me or not. Anyway, even with your method I can say it's parfocal.

  • nomadnomad

    Sorry, it's not about zooming in and out.

    Just focus at tele very carefully (wide open, of course) and zoom to widest, check if it holds focus.

  • MikhailKMikhailK

    @sam_rides_a_mtb it's very easy to find it out.

    You gotta zoom in and after that focus on some object. Then zoom out (and remember to stand on the same place). Then (standing on the same place) zoom in onto the same object. If this object is still in focus then your lens is parfocal.

  • sam_rides_a_mtbsam_rides_a_mtb

    @Mikhailk How do you know this lens is parfocal? From doing your own tests or did you read this somewhere?

  • MikhailKMikhailK

    @nomad, this lens is parfocal.

    @stonebat, Yesterday I looked at the front mount of my lens and noticed the following. I set f/2.8 and started zooming in. The more I zoom in, the more the aperture squeezes. Maybe I'm wrong but I have a conclusion that @Vitaliy_Kiselev was right:

    "As issue can be just with lens firmware error. It tries to keep F number during zooming, but fail to do it properly. ------- So, it can be non-constant F number zoom with electronic adjustment. ------- "

    Also you should keep in mind that during zooming with this lens while taking photos, you clearly hear the lens' motor and see this flicker effect. When you zoom in the cinema mode (without pressing the REC button) you also here this sound and see the same flicker effect. When you press the REC button this sound almost disappears, but this flicker effect is still there (it's getting less noticable but it's there).

  • stoneystoney

    As zoomin in, the aperture opening should get wider to keep the constant f-number. The f-number is a ratio :)

    I wonder if it's simply a firmware bug that doesn't sync the zooming and aperture opening. But I wouldn't believe it before seeing a test clip though.

  • chazzmoechazzmoe

    Does anyone know if when mounted on a Af100 and you adjust the iris if it's "hard" click like steps or is it smooth like a built in lens? I had the 14-35mm f2 which optically was great but if you were outside and the sun was moving in and out and you had to adjust the iris it pretty much killed the take.

  • nomadnomad

    If it's not parfocal, you can't film when zooming anyway…

  • gamebgameb

    Sounds like a real defect. Hmmm. But as long as it happens only during zooming... I am not a fan of zooming anyway. Its not really very filmic.

  • HillTop1HillTop1

    @Mikhailk wow, thanks for pointing this out. I was gonna place an order for this lens this Thursday. This is a bummer, panasonic didn't think people will notice?

    So could this be something that could be fixed via a firmware or some design flaw?

  • Vitaliy_KiselevVitaliy_Kiselev

    Those who wanna have a true "cinematic" zooming (without the brightness change) while shooting a movie/video, may forget about this lens.

    This thing needs carefully testing to understand why this happens.
    As issue can be just with lens firmware error. It tries to keep F number during zooming, but fail to do it properly. So, it can be non-constant F number zoom with electronic adjustment.

  • MikhailKMikhailK

    @bkmcwd,

    Thanks a lot for the confirmation. I also forgot to say that this effect (brightness changes in step) comes with a sound, as you said.

    I don't know about you or others who have this lens, but I'm very disappointed 'cause this lens is not a cheap one.

    @Vitaliy_Kiselev, yes, it's a bad sign. Those who wanna have a true "cinematic" zooming (without the brightness change) while shooting a movie/video, may forget about this lens.

  • bkmcwdbkmcwd

    @Mikhailk

    "I would appreciate if you could confirm my words, since you do have the same lens already."

    Yes, I also noticed the effect. Although I do not know how it should explain in English, brightness changes in step with a sound of an iris(?) operation.

  • nomadnomad

    We may need to treat it as a variable prime then, but it's not the fastest lens compared to real ones…

  • Vitaliy_KiselevVitaliy_Kiselev

    Unfortinately I can't upload a file for you to see it but trust me, this lens has it.

    This is quite bad sign.

  • MikhailKMikhailK

    Hi everybody,

    I've just tested my new Panasonic 12-35mm and I'd like to share with you some things I didn't like about this lens...

    The good points are for video-shooters:

    1. yes, it's very sharp.
    2. light in weight.
    3. nice bokeh.

    But, since most of us here on Personal-View are interested in video/cinema shooting, there are several things you won't like about this lens:

    1. it has some breathing - but it's not a problem, I suppose.
    2. while you zoom in/out during shooting a video you clearly see some "small' change in the scene in terms of lighting. The light changes a little bit but then (almost instantly) it goes back to the initial condition.

    This effect reminds me the same thing when you zoom in/out using a non-constant aperture lens. Of course, this effect is not that huge but you'll notice. Unfortinately I can't upload a file for you to see it but trust me, this lens has it.

    @bkmcwd, I would appreciate if you could confirm my words, since you do have the same lens already.

  • stoneystoney

    Sure it could... I mean all of m43 zooms could... in a million years.

  • everoevero

    @Vitaliy_Kiselev that would be a huge thing :) do you speak in terms of panasonic implementing it, or do you see a potential for investigating it?

Add a Comment