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Discussion in 'Open Discussion' started by PeterPrism, Sep 6, 2013.

  1. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    This is a Jpg File done with my beautiful, loved and hated X-Pro1 & 18mm original fujifilm at:
    f 3.6 - 1/160 sec - 800 ISO.
    This pic shows a strange (very ugly IMO) bokeh (see the enlargement below)
    Can you please explain in optical terms:
    (1) why it is present,
    (2) what is it,
    (3) if it is only a result of a digital camera or can be obtained also in an analog camera
    (4) if it is a problem referred to the lens or to the sensor,
    (5) if it is referred to the lens: do you think the zoom 18 --> 55 has the same problem?
    (6) if it is referred to the lens: what do you think if I replace 18 & 35 for a new 23?
    (7) how to prevent a future similar bad result ? [(obviously, don't tell me to reduce F-stop, I wish use the bokeh feature taking advantage of this fast (f 2) aperture lens)]
    Thanks to you all X-Friends!
    Peter

     

    Attached Files:

  2. bobmielke

    bobmielke FujiXspot Regular

    98
    Aug 25, 2013
    Portland, Oregon USA
    You've got bigger issues to solve before you need concern yourself about bokeh. Obviously your photo is not level. The lamp post is leaning like the Leaning Tower of Pizza. Your exposure has no dynamic range of highlights and shadows. You used a very wide angle lens that would have been better served filling the frame with the main subject, the cats. The rest of the composition is not only too busy but doesn't contribute anything to the subject. Attempting to blur such a huge uninteresting area is futile.

    When you use a wide angle 18mm lens you need to understand barrel distortion when composing before shooting. The cat to the right appears to have a white rear leg much bigger than his head. Moving to a side view would have reduced this effect. restrain from using a wide angle lens for human facial close-ups as the nose will appear gigantic. It's all about knowledge, of your camera and of your lens intent and shortcomings.

    Bokeh, the Japanese term translated as "blur" refers to the quality of out of focus areas of a photograph caused by a shallow depth of field. Everything in this photo that isn't sharp is distracting and serves no real purpose. Try cropping much closer, eliminating all that stuff. Be sure to straighten the photo first. Sample below:

    [​IMG]
     
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  3. jloden

    jloden FujiXspot Top Veteran

    708
    Mar 9, 2013
    Hunterdon County, NJ
    Jay
    Bokeh is a character of a lens mostly, so this may be partially to do with the 18mm. There are however a few things that would affect the bokeh look here:

    1) You're partially closed down to f/3.2; most lenses do best with smooth bokeh wide open, and the shape of the blades/aperture setting affects the shape and pattern.

    2) High ISO noise; the higher the noise, the more obvious any objectionable pattern is in the bokeh, in my experience.

    3) What's in the background; this looks like some kind of small pattern foliage being thrown out of focus. Sometimes foliage and other patterned backgrounds can look really weird when rendered OOF.

    4) You *might* be seeing a bit of CA or purple fringing in that upper right corner? It looks purplish to me, and that will look hazy and ugly. Not sure if that's the case but it looks unusual.


    Unfortunately I have barely used mine but I did dig up one quick example with the 18mm wide open and the bokeh looks fine to me:

    DSCF5780.
     
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  4. WT21

    WT21 FujiXspot Regular

    166
    Feb 1, 2013
    Based on PeterPrisms work (see here: https://www.fujixspot.com/f14/just-share-you-1334/) I would say his vision is not about proper proportions and straight lines.

    I actually rather like the picture, too.

    The blur, as jloden points out, is mostly due to the lens, but also exposure. It's very bright up there, perhaps triggering CA and other things. Overall, the bokeh looks nervous all around. Do try stopping it open a bit more. Also, I find the upper right hand corner a minor piece of the picture, so I wouldn't pixel-peep at it too much. I am not sure the 18-55 would be any better, as zooms tend to have nervous bokeh, too. Maybe try the 14mm lens, or a non-native prime, if you're not happy with the 18?
     
  5. jloden

    jloden FujiXspot Top Veteran

    708
    Mar 9, 2013
    Hunterdon County, NJ
    Jay
    I can attest that the 18-55 can also do perfectly smooth bokeh wide open:

    9654459641_cef15aef0c_c.
    Lake Maligne, Jasper National Park, Alberta Canada by jloden, on Flickr
     
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  6. Luke

    Luke FujiXspot Top Veteran Subscribing Member

    865
    Jan 31, 2013
    Milwaukee, WI USA
    Luke
  7. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    Ehm, i'm searching a tech answer to the problem, if you cut away the problem you will have a better photo but this was obviously not the fulcre of my thread. Thanks.
     
  8. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    Thanks really to you all ! But I don't still understand the white fringes on the green section of the enlargement. It is as a white rough paint. Thanks again.
     
  9. jloden

    jloden FujiXspot Top Veteran

    708
    Mar 9, 2013
    Hunterdon County, NJ
    Jay
    I'm with you, I do think there's some CA going on. Wonder if cleaning it up in LR would help?
     
  10. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    Perhaps the answer is in the middle and we have more factors in game.
    Now I think that the CA is strongly present (see the yellow trees in the enlarged pic).
    Second, the nervous bokeh is a reality with this lens (see this picture in normal condition to the left-up corner with the same 18).
    Third the contrast is very high so the white is completely blown out and this makes the contour more "cutted"
    Thanks.
    WHS_DSCF5438.
     
  11. bartjeej

    bartjeej FujiXspot Regular

    139
    Mar 31, 2013
    Bob, since it's all about knowledge, please allow me to make a few comments.
    1. It's the tower of Pisa. (ok this is just nitpicking, sorry!)
    2. The difference between the size of the cat's leg and its head isn't due to barrel distortion but due to perspective "distortion" (it's simply a logical result of differences in relative distance as portrayed using correct rectilinear perspective; one could argue it isn't actually distortion, but alas). I see no obvious barrel distortion anywhere in the image.
    3. Boke(h) simply means blur(riness), and you can have lots of it, little of it, nice bokeh, unpleasant bokeh (such as here). In any event, the term bokeh is not limited to just the quality of the out-of-focus areas.
    4. (and this is not so much a knowledge / factual issue), the quality of art is subjective, and therefore, art doesn't have to follow rules :smile:
     
  12. Luke

    Luke FujiXspot Top Veteran Subscribing Member

    865
    Jan 31, 2013
    Milwaukee, WI USA
    Luke
    I would selectively remove all color in the sky since some areas are so blown out already anyways. At least it would be consistent, then. Because the same problem exists in the upper left corner as well.

    And in reference to the "nervous" bokeh in the second example, that's just going to happen with busy patterns of bright colors. We love lenses that are contrasty, but we also want lenses that give us smooth, buttery bokeh. You just can't have it both ways. By the way, I love that little robot. Does he have a cassette in his belly?
     
  13. bartjeej

    bartjeej FujiXspot Regular

    139
    Mar 31, 2013
    I don't think LR allows you to desaturate just the blue or purple parts of a certain selection, but I'm pretty sure the GIMP does. If you make a feathered selection of the parts containing CA and then just desaturate those colours, that should get you a long way, shouldn't it?
     
  14. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    Thanks for your thought. Yes it shows a cassette!
     
  15. Luke

    Luke FujiXspot Top Veteran Subscribing Member

    865
    Jan 31, 2013
    Milwaukee, WI USA
    Luke
    The Gimp would certainly do it. I rarely use my Lightroom anymore...is there no smart selection tool?
     
  16. bartjeej

    bartjeej FujiXspot Regular

    139
    Mar 31, 2013
    In LR4 at least, there isn't. You can make "selections" by using adjustment brushes, but the range of edits you can make locally is somewhat limited - no colour curves or HSV, unfortunately...
     
  17. PeterPrism

    PeterPrism FujiXspot Regular

    45
    Feb 16, 2013
    Italy
    Thanks to you all for the contribution.
    Cheers, Peter