What causes swirly bokeh?

Discussion in 'Open Discussion' started by Mellow, Apr 18, 2012.

  1. Mellow

    Mellow Mu-43 All-Pro

    Aug 27, 2010
    Florida or Idaho
    I sometimes enjoy pictures with distinctive 'swirly bokeh', like the kind produced by my beloved Hobson Cooke Kinic 25mm f/1.4:
    marina-flower-small. kinic-8059093.

    Seeking this look I recently purchased a Helios 44-3, which is supposed to have the same qualities. For example, see this: Swirly Japanese maple | Flickr - Photo Sharing!. The Helios is based on an old Zeiss biotar design, and from my understanding the only differences among the different versions are the coatings and number of aperture blades. The optical design is identical.

    However the copy I received was completely unable to produce any kinds of swirls, no matter how I tried. None! So that got me thinking (always a dangerous thing) . . .

    What lens characteristic causes swirly bokeh? I thought I'd read that it is a result of astigmatism, but if this is true then shouldn't all copies of the same lens, with the same design, produce the same result? Or is it something else--a result of misalignment, so that a lens that's been knocked around might produce swirls (or not) compared to one that's in better condition? I truly don't know and am appealing to the lens experts in here (you know who you are!) for an answer.
    • Like Like x 2
  2. littleMT

    littleMT Mu-43 All-Pro

    Apr 8, 2012
    Lucille Sanchez
    I believe SLR Magic makes a Bokeh lens for us that produces the swirly bokeh... and its cheap..
  3. Minniesmum

    Minniesmum Mu-43 Veteran

    Mar 2, 2012
    Good question ! My Pentax Auto 110 70mm lens produces incredible swirly bokeh but has no aperture blades. It's a fixed f2.8. I wonder too....
  4. songs2001

    songs2001 Mu-43 Top Veteran

    Jul 8, 2011
    The NEX has a larger sensor, so if you use the same lens on the M43, a portion of the swirls will be cropped and you'll get a less swirly effect.
  5. Timos L

    Timos L Mu-43 Top Veteran

    Dec 26, 2011
    Athens, Greece
    Timos :)
    I think (without being certain) that swirling bokeh is a result of a cheap lens that misses the elements that correct this effect.

    So far I have nice results from a cheap chinese 25/1.4 cctv lens on a m43 sensor:

    6873825705_cc6db33f21_n. ... 6864991157_991fd5eb9f_n.

    6861592775_fb7aea5d69_n. ... 6860607693_17217317db_n.
  6. slith

    slith Mu-43 Regular

    Apr 4, 2012
    Dublin, Ireland
    If you google swirling bokeh the first reference comes from someone claiming swirling bokeh happening on a Noctilux, not exactly a cheap lens.

    I think it tends to happen more when you shoot wide open.
  7. Justified_Sinner

    Justified_Sinner Mu-43 Regular

    Feb 11, 2010
    Scotland, UK
    Dauvit Alexander
    Someone mentioned to me some time ago that lens designers can only have out-of-focus elements looking good in either the foreground or the background but not both. Perhaps it has something to do with this?

    Earlier this year, I took this shot with a Minolta Tele-Rokkor 135mm f2.8 and was amazed by the bizarre rendering of the foreground branches:

    <a href="http://www.flickr.com/photos/the_justified_sinner/6951929159/" title="Camelia by the justified sinner, on Flickr"> 6951929159_c96a3e6ef9. "500" height="375" alt="Camelia"></a>​
    The same lens is quite capable of a very lovely rendering of the background:

    <a href="http://www.flickr.com/photos/the_justified_sinner/6872850458/" title="Stickered by the justified sinner, on Flickr"> 6872850458_62275a7d36. "500" height="375" alt="Stickered"></a>​
    The lenses discussed in the thread above could have been designed to make the foreground rendering better. (But this is only a suggestion: I have no idea if it is correct or not!)
  8. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    See the wacky aperture blade shape here?
    I thought that's the cause of swirly bokeh.
    • Like Like x 1
  9. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    ...and the trend these days is to have circular aperture blades for the smoothest, creamiest bokeh possible.
    • Like Like x 1
  10. Crdome

    Crdome Mu-43 Hall of Famer Subscribing Member

    Sep 11, 2011
    West Central Indiana
    My immediate reaction to the photo of your Toy lens is the improperly aligned shutter leaf is not functioning correctly. It should be symmetric.


    I thought that's the cause of swirly bokeh.[/QUOTE]
  11. kinlau

    kinlau Mu-43 Top Veteran

    Feb 29, 2012

    It's the lens formula or design that causes the swirls, and for the kind of heavy swirling you're looking for, a lens meant for a smaller format like CCTV, 16mm, 110, will likely be your best bet. The large format guys use old projector lenses, and they're rather sought after.
  12. Mellow

    Mellow Mu-43 All-Pro

    Aug 27, 2010
    Florida or Idaho
    That would make sense, though I would have thought I'd be able to see a HINT of swirling when I tried to create it. Do you if the lens defect is astigmatism that causes the swirls?

    Thanks for the reply.
  13. kinlau

    kinlau Mu-43 Top Veteran

    Feb 29, 2012
    Can't really remember the terms any more. It was a few years ago when I spent some time checking out large format.

    Can you post a few shots with the Helios?
  14. nueces snapper

    nueces snapper Mu-43 All-Pro

    I have seen that exact same effect (the rose) using a Nikon D3 and f/2.8 70/200 L lens. Not often however.
  15. Crdome

    Crdome Mu-43 Hall of Famer Subscribing Member

    Sep 11, 2011
    West Central Indiana
    Mellow, I understand your desire, but I think you are trying to compare apples with oranges here.

    The lenses attributes and sample photos are too dissimilar. The Hobson Cooke Kinic 25mm f/1.4 is a 16mm film lens thats image just covers the sensor. In the m4/3 format it has a normal 50mm FOV, with a huge aperture. As a small center focused lens the vast portion of the image is "peripheral field" shot through lens' edge curvature.

    The Helios 44-3 is a 58mm F/2, 35mm film lens with an equivalent 108mm telephoto DOV and a decent aperture. Shooting wide open the portion of the image circle that falls on the sensor is from the center of the glass, not the extreme center-to-edge convex as the 25mm's. Since only about 1/4 of the image circle falling on the sensor, I don't think you can expect the same bokeh.

    Your comparison photos are also too dissimilar to compare bokeh. The Hobson Cooke Kinic photo is a closeup with a background of less than feet away. The Helios back ground is many feet to hundreds of feet away. The Helios shows does display some nice 'swirly bokeh' thought not as distinct here. Try shooting a nearly identical composition as possible to the Hobson, and I think you may find the more concentrated swirl.

  16. Mellow

    Mellow Mu-43 All-Pro

    Aug 27, 2010
    Florida or Idaho
    Thanks for the reply. I think you're absolutely right about the image circle/sensor thing. Much of what I see in my Kinic wasn't even designed to be captured on the format it was designed for. In contrast, the 3/4 of what the Helios WAS designed to capture falls outside the m43 sensor.

    However, with regard to the Helios, I did really try to produce swirls--using all sorts of combinations of aperture, distance, background, etc.--and I couldn't. At least as far as my copy is concerned, it doesn't 'swirl'. Nice and sharp, with interesting bokeh, but not swirly bokeh.
  17. kinlau

    kinlau Mu-43 Top Veteran

    Feb 29, 2012
    I think the point Crdome is trying to make, is that the swirly bokeh doesn't occur in the center part of the image, it always along the outside part of the image, and that's exactly where m43 sensors crop away.
  18. Crdome

    Crdome Mu-43 Hall of Famer Subscribing Member

    Sep 11, 2011
    West Central Indiana

    I see overall swirl from the Helios on my monitor. But your subject content is mostly solid, vertical lines, i.e. trees. Shoot a closeup of a bush like object and the bokeh will be much easier to see. -Chrome
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