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Thread: Vignetting effect

  1. #41
    Member lennyl's Avatar
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    Default Re: Vignetting effect

    This is getting ridiculous. What you said:

    Quote Originally Posted by Nenjia View Post
    just try. if in spot mode, see vignetting, try to switch to matrix, it might be improved -- but no guarantee, depends on light condition you are facing
    Of course there's no guarantee. If you're lucky, and the camera's AE happens to pick a smaller aperture, vignetting goes away.

    The dpreview thread talks about metering accuracy and how vignetting affects it. In fact, in the first thread, if you look at the images in the first post, it shows very convincingly how vignetting is reduced drastically when lens is stopped down.

    http://forums.dpreview.com/forums/re...ssage=21716396

    Ignore the text, just look at the aperture setting for each image. At f/2, vignetting. At f/5.6, no vignetting.

    You have displayed a lack of understanding of the issue, and then proceed to go about trying to ridicule everyone who has tried to correct you. If it makes you feel better, continue to do things your way. But please refrain from trying to mislead others.

    Edit : I continue reading your posts, and decide you can't possibly be serious. Now you're dragging in white balance? Quoting pages from the CODE V optical design software? What next? CF card type? Sunspot activity? Should I consult my astrology chart? Mars in Libra means vignetting might occur when I shoot within 500 km of Tom Cruise.
    Last edited by lennyl; 5th October 2008 at 05:51 PM.

  2. #42

    Default Re: Vignetting effect

    Quote Originally Posted by Nenjia View Post
    as your post is new, he is NOT talk about metering with vignetting, he is talking about how metering works, all another people talk about something!
    my post is connected to my previous post, #27... and what Octarine was talking about was your idea that vignetting and metering modes were related... which in post #27 I have tried to point out they are not related as you have stated... and in post #37, and again here, I urge you to re-read John Hedgecoe's books regarding metering and vignetting
    Quote Originally Posted by Nenjia View Post
    so if someone wants to win, I am OK -- I already said if i am mis leading you, i am sorry!

    I am wrong, you are right, that will improve you skill on photography/ feel better now?
    this is not about winning or losing... its about not misleading the TS who asked a question, or others who might have the same query
    Quote Originally Posted by Nenjia View Post
    does anyone know sometimes white balance is also possible to link with vignetting?

    people normal do not mention the metering and white balance highly because they know when and where, what to be chosen.

    hehe, hope helping you not confusing you!

    we are talking about vignetting effect on final result of picture without post processing/filter and hood!

    the factor might be F stop, metering and even white balance!
    if this is as lennyl suggests a purposeful effort to mislead the TS, then its a pretty sad thing to do to the TS who had a genuine question... if this is not purposeful, I apologize for suggesting that it is but recommend that your facts need to be checked...

    and to the TS, neither white balance nor metering mode will affect vignetting
    Last edited by theRBK; 6th October 2008 at 02:29 AM.

  3. #43

    Default Re: Vignetting effect



    hmm, I feel much better now, please don't go crazy, let go back to basic:

    someone defined 4 kinds of vignetting :

    Mechanical vignetting
    Optical vignetting
    Natural vignetting
    Pixel vignetting( digital only)

    when people discuss hood/filter caused the vignetting, they may take off the hood/filter or even file off the hood/edge of filters or using a up size filter, even stopping down the aperture can improves too, but lesser mentioned

    when people discuss the lens quality caused the vignetting, they may focus on F number, stop down the aperture ( by the way, for large F number, actual is prolong the shutter let same amount light flows in by longer time) by fix other conditions

    these 2 cases appear in most of lenses review, so people only see F number/hood/filter....

    when light condition not even, or nature affect, you have to change metering or even white balance to have better result ot improving

    in this case, the picture shown in this thread, might be due to larger aperture and fast shutter, and also the spot/center metering caused under exposure!

    to come out a good picture, you need using a right way, not only lens, not only filter/hood, even not only the set of equipment, you need think of all factors.

    hope this helps!

  4. #44
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    Default Re: Vignetting effect

    All bloody misleading. To no end. And it doesn't help that one has his head so bloody high in the clouds.

    If my lens has inherent vignetting, no matter how I meter, the corners will still damn well be darker than the center. How can metering affect the light coming from one particular plane (such as the corners of the image)?? When light is not even, it is not even. Just by changing the way the camera reads and registers exposure does not even out the light for you.

    In the same way, an uneven road will not be evened out by changing which car you use and which direction you drive over the uneven road; it only changes when the road itself is repaired.

    No need to belittle all of us, mislead everyone, and then continue to insist on your point when you do not even fully understand what you are blabbering about.
    Last edited by calebk; 6th October 2008 at 11:00 AM.

  5. #45

    Default Re: Vignetting effect

    ok, ok, i give up

  6. #46

    Default Re: Vignetting effect

    Quote Originally Posted by Nenjia View Post
    when people discuss the lens quality caused the vignetting, they may focus on F number, stop down the aperture ( by the way, for large F number, actual is prolong the shutter let same amount light flows in by longer time) by fix other conditions
    actually, stopping down the aperture does not reduce optical vignetting (or any other forms of vignetting) by forcing a longer exposure... increasing exposure duration would merely let in more light throughout the image... thus the vignetting-shaded area might receive more light, but the area not shaded by vignetting would also receive an increase of light, possibly overexposing the image, and still the difference in brightness between centre and periphery would remain...

    optical vignetting is caused by the shading of the light entering the lens due to the length of the lens structure... reducing the aperture reduces the appearance of optical vignetting by restricting the angle at which light enters the lens, such that there is a reduction of shading caused by the length of the lens... this reduces or eliminates the occurrence of optical vignetting...

    natural vignetting is not caused by the natural illumination of the scene but by the design of the lens... it is due to the simple fact that as light spreads, the intensity of light decreases as the angle (as measured from the exit pupil) from the centre increases... thus, within the cone of light hitting the sensor, the light at the centre is more intense than the light at the periphery, all other factors being constant... lenses that project light on the sensor at a relatively steep maximum angle for its cone of projection would thus be more prone to natural vignetting than one that is less steep, all other factors being equal... this cannot be eliminated by stopping down the aperture...

    to read more about optical and natural vignetting, and also mechanical vignetting, this is a great article that unfortunately can get pretty technical...
    Quote Originally Posted by Nenjia View Post
    when light condition not even, or nature affect, you have to change metering or even white balance to have better result ot improving
    could you perhaps explain the mechanism by which metering and white balance can reduce vignetting?

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