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Questions regarding G1 with 14-45 lens

Discussion in 'Panasonic Cameras' started by mircea81, May 11, 2010.

  1. mircea81

    mircea81 New to Mu-43

    3
    May 11, 2010
    Hello everyone.

    I own a G1 camera together with 14-45 kit lens since december. There are some things I don't understand / like.
    I hope I'm not saying anything stupid, so please excuse me if so.

    1. It seems like at wide angle, the images produced have some distortions.
    You can see what I mean in the 2 pictures below:
    P1020747.
    P1020747_pp.JPG

    First one is straight out of camera, where you can clearly see distortions on the persons in the left.
    Second one is corrected using Lens Correction in Photoshop CS4 by -10.

    From what I read, the camera automaticaly removes distortion and chormatic aberations when shooting JPEGs.
    But I'm not sure this happens. Is this normal? If yes, than do I have to correct every wide image I shoot?
    How does your G1 do in this respect?
    Unfortunately, I don't have other wide (28 mm) camera to compare with.

    2. I noticed that the autofocus is not so good in low light. AF strugles a lot or doesn't focus at all if there are no contrasty objects.
    I compared the focus agains a Canon A590IS pocket camera that I have.
    The pocket camera focuses with no problem on a plain wall, in low light, while G1 doesn't focus at all.
    I tested this in a room with a desk lamp in one corner while trying to focus onto the oposite wall.
    The camera focuses very well in good light, no problem at all.
    Does anyone noticed this? How does your G1 do when focusing in low light?

    Thank you in advance
     
  2. tam

    tam Mu-43 Regular

    107
    Apr 12, 2010
    See here

    https://www.mu-43.com/f43/raw-processing-interesting-2553/

    for lens correction musing. Jpegs are indeed corrected. Shoot a grid like i did and you can easily test.

    With no contrast on a plain wall it cannot focus - it's a limitaiton of the focussing method. In practical use I've had no low light focus issues. Be careful not to cover the assist light with your left hand.
     
  3. mircea81

    mircea81 New to Mu-43

    3
    May 11, 2010
    Thank you for your reply. In your topic, you are talking about RAW files, which are uncorrected.
    The example above (first picture) shows JPEG file straight out of camera, not RAW. JPEGs should already be corrected. Maybe they are corrected but as you can see, the result is not nice.

    Regarding focusing in low light, I am being careful not to cover the assist beam. It's not that I had any issues in practice, but the thing that bothers me is that a pocket camera, a quarter of price compared to G1, focuses better in low light. :frown:
     
  4. tam

    tam Mu-43 Regular

    107
    Apr 12, 2010
    i have the jpegs too from my grid test, and they seemed corrected fine. i'll go back and recheck them though when i ge the chance and repost them.
     
  5. mircea81

    mircea81 New to Mu-43

    3
    May 11, 2010
    Distortion Article: 1. Page 1: Digital Photography Review

    Well it's not Panasonic, they are comparing an Olympus DSLR with an Olympus Micro 4/3. But the results are probably similar for Pana.
    As you can see, even with the in-camera correction, the final image still has distortion (1.8%) , and it's even worse then DSLR (1.38%).
    This is really annoying, as you can see in the above pictures.
     
  6. rst

    rst Mu-43 Regular

    109
    Jan 25, 2010
    Germany
    Yes it is correct, Panasonic does some corrections of lens errors in the jpgs and also stores parameters in the raw files so that the raws can be corrected in the raw converter (if the converter takes the stored data into account).

    Well, that being said, it has nothing to do with the effects you are seeing here. What you realize in your image is a different effect (and I am glad that this is not corrected automatically). It has to do with perspective distortion when using wide angle lenses. This effect has to do with angle of view and you will see it with all wide angle lenses. I do not want to go into much detail about this here since it is much better described than I can do here: Perspective Distortion

    Cheers
    Ruediger