July 29, 2014, 07:52:02 AM

Author Topic: Bokeh confusion.  (Read 5841 times)

Studio1930

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Re: Bokeh confusion.
« Reply #15 on: December 27, 2012, 03:10:02 PM »
Use a tilt shift lens or an easier way would be to use the Brenizer method.  I do this with my 85L.  Google it.

http://www.ryanbrenizer.com/category/brenizer-method/


btw, studio1930, thanks for sharing that link!  I've considered doing something similar in the past without being able to determine why it made sense, but now it's super obvious.  I do think that the OP's shot is a perfect opportunity for using the Brenizer method since it's mostly a still-life where the model only takes up a small portion of the overall image and is holding a pose than can easily be held still for a half a dozen frames or so.


No problem.  I also agree that the Brenizer method is perfect for the OP.  I love the way it simulates what medium format can often do.  I actually have a project coming up that will use this method. 

Happy stitching.
-Darrin
Studio 1930
www.studio1930.com

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Re: Bokeh confusion.
« Reply #15 on: December 27, 2012, 03:10:02 PM »

sdsr

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Re: Bokeh confusion.
« Reply #16 on: December 27, 2012, 03:33:16 PM »
bokeh isn't just about focal length and aperture, it's about the relationship between the distance from backdrop to camera and subject to camera.

in the first image, the backdrop is very far away, but so is the subject.  thus the backdrop->camera vs subject-> camera ratio is very small.

in the second image, the backdrop is probably moderately to very far away, but the subject is very close to the camera.  the backdrop->camera vs subject->camera ratio is very large, giving big, soft blur.

when you're trying to hit a certain amount of separation, always think in terms of how far your background is versus how far your subject is.  it's equally as important as what the absolute focal length of the lens is.

That all sounds about right, but even then different lenses respond, well, differently, and it matters what the background is.  I've noticed that if leaves/branches/twigs are in the background at a certain distance in relation to the subject and the camera (I've not tried measuring it), some lenses emphasize the lines and angles.  It was true of a Pentax 55-300 I used to own and is true of the 100-400L and 70-200 2.8 II I fairly recently rented, especially the former which, in almost every photo I took one afternoon, created extremely busy backgrounds that I disliked quite a bit; it's perhaps the main reason why I bought a Sigma 50-500 OS instead - it's much smoother.  Nor have I noticed busy bokeh from my 70-200 f/4 IS, even if it doesn't throw backgrounds out of focus to quite the same extent as the 70-200 2.8 II at 2.8.  And I was very pleased (and somewhat surprised) by the blur that my 24-105L created at 105mm in some silly photos I took while wandering around a kitchen supply store the other day; objects merely a few inches away from the subject (pepper mills, in one case)  blurred away very nicely.  It's no surprise that I've never seen busy bokeh from my 135L....

sanj

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Re: Bokeh confusion.
« Reply #17 on: December 27, 2012, 10:28:51 PM »
Infared: Yes it helped, thx! I will watch out for more bokeh issues with the 70-200 your point in mind that this lens does not have a 'creamy smooth' bokeh.

Packlight: Thank you.

Studio 1930: I will find time to go through the link asap. Thank you for it, am looking forward to discovering something new..


sanj

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Re: Bokeh confusion.
« Reply #18 on: December 27, 2012, 10:35:49 PM »
Ray2021: Yeah I agree about the top corner distortion. I do not like it at all.. I will experiment with your suggestions. Thx..

Rj79in: Thx for commenting and I believe that you find confusing OOF areas as the shot is taken from an angle. Perhaps..

Orangutan: Yeah, the dirt does not make good bokeh. Perhaps that is the main problem. Agree about the blue idea, it occurred to me too. :)

Scrappydog: Thanks for introducing me to term 'radical bokeh'. Going by the bathtub shot, 70-200 seems to suffer from it. Or is that a radical statement? :)


RS2021

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Re: Bokeh confusion.
« Reply #19 on: December 27, 2012, 11:36:51 PM »
I think he meant "radial" but your version works too  :P
“Sharpness is a bourgeois concept” - Henri Cartier-Bresson

Nishi Drew

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Re: Bokeh confusion.
« Reply #20 on: December 28, 2012, 12:06:56 AM »
I like radial/swirly crazy bokeh, as long as it's smooth enough, and as the above shot isn't bad at all.
While if anything, the overexposed table top on the second shot is rather unpleasant IMO

Aglet

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Re: Bokeh confusion.
« Reply #21 on: December 28, 2012, 12:39:47 AM »
I find a practical solution is to NOT USE THAT LENS.
Choose something else when you know you'll have somewhat fine textures in the focus transition zone.

For all it's fabulous sharpness and great IS it has too much CA and horrid bokeh in such situations.
Have a look at a recent shot I put in the lens gallery as an example.

Since I got this lens last year I've been amazed at the sharpness and dismayed by the bokeh, often in the same shot.
I preferred my old, non-IS 70-200mm for better bokeh.  Might still grab a used one for the purpose.

If time and planning was possible, I'd have shot that scene with a prime.

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Re: Bokeh confusion.
« Reply #21 on: December 28, 2012, 12:39:47 AM »

sanj

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Re: Bokeh confusion.
« Reply #22 on: December 28, 2012, 02:22:42 AM »
Radial radial radial. Not radical radical radical..... Opps.

sanj

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Re: Bokeh confusion.
« Reply #23 on: December 28, 2012, 02:24:55 AM »
Aglet: I would struggle if I did not use that lens... I find that it has a very useful focal length range..
But yeah the bokeh going by what we see here does seem weird. It is almost as if the camera was rotating on its axis as the shutter was pressed.

sanj

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Re: Bokeh confusion.
« Reply #24 on: December 28, 2012, 02:34:39 AM »
Nishi: I will keep the burn out in mind when I post process. However at this point I kind of like it. :)

Sdsr: Thx..

Sporgon: I see your point. :)

And am relieved to realize that I was right in not liking the bokeh, it comes from one of Canon's landmark lens...

Aglet

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Re: Bokeh confusion.
« Reply #25 on: December 28, 2012, 01:53:43 PM »
Aglet: I would struggle if I did not use that lens... I find that it has a very useful focal length range..
But yeah the bokeh going by what we see here does seem weird. It is almost as if the camera was rotating on its axis as the shutter was pressed.

I hear ya.  I'd love it if I could just use this lens and not be concerned about ugly bokeh showing up.
but it does, so be aware of the weaknesses of whatever gear you're using.
Just because it cost a lot and came with an "L" in the moniker does not mean it's perfect.

It's a lens with compromises, as most are, unfortunately.
My new Nikon 70-200 f/4 VR shows some of the same effect.  I knew this before I bought it as I could see the radial blur effect in a sample image someone posted from an early production sample.  The shot was of grass, at a shallow angle, so you could see the blur quality around the central focus area.  In the full size shot it was hard to notice the radial blur but in the small thumbnail size image it was grossly obvious.

What I've seen from modern zooms is more of this radial bokeh tendency.  I'm no lens designer but I think this is the price we pay for zooms that are super sharp with well controlled CA.  Subjects in the focus zone are rendered very accurately but those just in front and behind get some strange distortion that seems to be caused by the special elements which are used to provide the corrections that give the focused area its sharpness and color convergence.

For anyone shopping for zooms tho, you can see this effect in the viewfinder if you can aim at some suitable subject matter tho.  I find that tree branches in backgrounds, especially those where you also have plenty of sky available for contrast between them, will often show this distorted bokeh.  Just focus the lens in front of or behind the branches and play with focal length, focus position and aperture and you'll see the distortions show up as you make the changes.  On my 70-200/2.8 v2 I noticed entire sections of blurred branch actually disappearing at some settings! Very strange!

In general, I'm finding these radial bokeh effects show up more at close focus distances and at wide aperture settings.  They often diminish in effect when stopping down.
Your mileage may vary.

This is just another instance of where you need to be wary when everyone raves about how good some piece of gear is.  There's often a catch that's not been discussed as well.  Forums like this are good education opportunities.

Knowing this I've kept a lot of lower quality lenses on hand for just this reason.  Altho a cheap lens will rarely provide the biting sharpness of the pro glass, they'll also rarely show these same distracting aberrations.  They'll have their own problems of course.  But a $200 lens may provide you a workable option when the $2000 one fails in this way.  Some of my best images were made with second-hand consumer grade lenses merely because they provide a balanced "look" with adequate sharpness and smooth bokeh.  I wouldn't expect these cheap lenses to perform well at a race-track though, they focus too slowly.

sanj

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Re: Bokeh confusion.
« Reply #26 on: January 02, 2013, 02:41:31 PM »
Thanks so much!

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Re: Bokeh confusion.
« Reply #26 on: January 02, 2013, 02:41:31 PM »