Bokeh Question

Discussion in 'Adapted Lenses' started by Boatman, Apr 22, 2011.

  1. I took this photo with a Takumar 1:1.4/50 at f-2.0. The bokeh circles, which I recall were caused by very bright reflections off some swampy grass, are not round. They are clearly the exact shape of the 8-element diaphram in the lens and you can even see the corners where they hook a bit.

    Is this normal? How can you get a rounder image or prevent the clearly octagonal shape?

     
    • Like Like x 1
  2. Either shoot wide open when the diaphragm blades are retracted or try to avoid backgrounds with any point light sources or reflections.
     
    • Like Like x 1
  3. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    Yep, it's normal.
     
  4. mauve

    mauve Mu-43 Top Veteran

    892
    Mar 9, 2010
    Paris, France
    Yep, open up @f/1.4 ... no diaphragm to cast that octagonal reflection then !

    (I'm dead serious, that's the only solution - now you understand why some would use a ND filter sometimes too)

    Cheers,
     
  5. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    SoCal
    Many lenses incorporate a Nine Leaf aperture to a smoother ... more pleasing bokeh. (Or pick up a mirror-reflex lens for circular doughnut looking highlights.)

    Gary
     
  6. Actually you're not doing too badly to have an eight-bladed diaphragm. Five blades will really get you into trouble!
     
  7. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    I find it interesting that some of the circles are very clear, while others are more blurred. Do you have a filter on the lens?
     
  8. f6cvalkyrie

    f6cvalkyrie Mu-43 All-Pro

    Feb 12, 2010
    Brussels, Belgium
    Hi,

    the more, the merrier, and that also applies to the number of leafs in the diaphragm. I have some lenses, like the trioplan 100/2.8 that have 15, so the highlights stay nice and round, even when stopped down.

    Here's an example, if you don't mind :

    sized_P1160046.

    Have fun,
    Rafael
     
    • Like Like x 4
  9. Great comments, thank you all. I confess, I'll have to look up Trioplan - never heard of it. Lovely photo! I do have a polarizing filter that cuts a couple of f-stops. I'll remember to use it, if necessary.
     
  10. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    SoCal
    15 blades wow ... didn't know such a beast existed.
     
  11. acercanto

    acercanto Mu-43 Regular

    107
    Apr 15, 2011
    SW VA, USA
    In a similar note, is there any way to adjust the blades at all to remove that hooking? I just got my first piece of old glass, a Konica Hexanon 40mm f1.8, and on close inspection, the blades aren't perfectly aligned.
    P1050658.JPG

    Also, this lens has an Auto Exposure tab in the mount, will it still fit a normal AR mount?

    Thanks,
    Acer
     
  12. Orientator

    Orientator Mu-43 Regular

    48
    Dec 7, 2010
    effect known...

    With my old OM Tokina 28mm lens I've taken this extreme example of the effect of those blades...

    Stefan
     

    Attached Files:

    • Like Like x 2
  13. jbuch84

    jbuch84 Mu-43 Veteran

    233
    Feb 9, 2011
    Orlando, FL
    James
    Acer, that's what most lens will look like when not using with the aperture wide open, it's just the way they close. At 1.8 it should be a prefect circle
     
    • Like Like x 1
  14. Jman

    Jman Mu-43 Veteran

    475
    Apr 20, 2011
    Columbus, OH
    Ye olde Ninja Star Bokeh. Many older lenses have it, including the AE version of the classic Zeiss 85mm f/1.4 Planar T*. The nice thing on the Hexanon 40/1.8 is that it's only there at f/2.8. f/4 is fine as is f/1.8.
     
    • Like Like x 1
  15. A number of lenses display a similar "jagged" iris opening, usually at about one stop off wide-open. Offhand the OM Zuiko 50/1.4 has an extremely mild case of this, and the Industar 61 has a wild looking aperture through most of the range.
     
    • Like Like x 1
  16. acercanto

    acercanto Mu-43 Regular

    107
    Apr 15, 2011
    SW VA, USA
    Thanks for the confirmation, everyone. I was hoping I didn't get a lemon for my first piece of legacy glass. Orientator, that photo also helps, because my blades aren't exactly even all the way 'round, and it appears as if yours aren't either. I assume there's no way to tweak them into evenness? I've got an AR adapter in the mail coming my way, but I'll be sure to post some pics at different apertures in the adapted lens section.

    Acer
     
  17. theanswer03

    theanswer03 New to Mu-43

    1
    May 4, 2011
    Hi, may i ask what camera u're using the Trioplan on? Which adapter should i get to mount it on a M43? Thanks!
     
  18. Warren T.

    Warren T. Mu-43 Veteran

    338
    Mar 10, 2010
    San Francisco
    Hi Acer, good choice on your first adapted legacy lens :smile:. I'm very pleased with my Hexanon 40mm. It has a bit of a split personality. At wide open, the lens is soft and dreamy, but stopped down by one click or more, it's razor sharp. And the pancake size makes it fit very well on the M43 bodies. To answer your question, yes, it will fit on a standard AR to M43 adapter. I believe the jagged bokeh only appears at the first click (f2.8, I think), smaller apertures are smoothly rounded.

    --Warren
     
  19. David Tait

    David Tait Mu-43 Regular

    73
    Apr 29, 2011
    Hi Acercanto. You might check out this info about your Hexanon 40mm. It answers your questions.

    Konica Hexanon 40mm f/1.8 at Teeeeejirrrrr

    Dave T.
     
  20. acercanto

    acercanto Mu-43 Regular

    107
    Apr 15, 2011
    SW VA, USA
    Thanks Warren, that's exactly what I've found. I took it out for an inaugural spin the other evening, and you're absolutely right about it being sharp one stop down. Also came up with some very cool lens-flare-type-things when shot into a light.
    5682705990_7ea7550e32_z.
    Bisset Park tennis courts by acercanto, on Flickr


    Very cool link, Dave. I've got it bookmarked now, and will probably reference it often.

    Thanks,
    Acer