
About Bokeh - luu
http://www.bokehtests.com/styled/
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virtualritz
I am surprised about how biased this article is in assigning attributes like
‘good’, ‘bad’ or ‘perfect’ to Bokeh shapes. You can talk about this in these
terms solely from an optical engineering pov.

The shape of Bokeh is often why a lens get picked for a shot.

What the author calls ‘bad Bokeh’ other people call ‘soap bubble Bokeh’
(google for it) and they are willing to cash out [2] for owning a lens that
can produce this sort of thing. This is an artistic choice[1].

This article’s generic statement that this sort of Bokeh creates images where
the out of focus BG areas distract from the FG/in focus motive shows a narrow
understanding of how Bokeh can be used in composing an image.

[1] [https://www.shutterbug.com/content/creating-unique-macro-
ima...](https://www.shutterbug.com/content/creating-unique-macro-images-
vintage-meyer-optik-goerlitz-%E2%80%9Csoap-bubble%E2%80%9D-lens)

[2] Caveat: I bought a Meyer Optik Trioplan 100mm f/2.8 replica on Kickstarter
for this very reason: the ‘bad’ soap bubble Bokeh. I love this lens.

~~~
vilhelm_s
The "bad" pattern he calls out is not exactly the Trioplan soap-bubble style,
it's the thing you get from a mirror telephoto lens.

In Trioplan images[1], the light intensity smoothly increases towards the edge
of the disk of confusion, and creates a sharp edge. I agree that this looks
kind of nice, although it's a quite specialized effect.

In mirror lens images[2], the "disk" of confusion is actually a ring, with
_two_ sharp edges rather than just one. This is not at all pretty, and as far
as I know basically nobody buys these lenses for this effect.

This actually matters a lot, because other than this, mirrors are superior to
refractive glass lenses in almost every way (note that astronomical telescopes
are always mirror-based), so if it was not for the bad bokeh we'd all use
them.

[1] [https://fujilove.com/the-legend-and-the-bubble-bokeh-
review-...](https://fujilove.com/the-legend-and-the-bubble-bokeh-review-of-
the-meyer-optik-goerlitz-trioplan-100mm-f2-8/) [2]
[https://hoaiphai.wordpress.com/2011/10/18/recumbent-
review-t...](https://hoaiphai.wordpress.com/2011/10/18/recumbent-review-the-
mighty-reflex-nikkor-c-500mm-f8/)

~~~
kabouseng
>>This actually matters a lot, because other than this, mirrors are superior
to refractive glass lenses in almost every way

No. Reflective designs (mirrors) are usually of the casigrain type, and
casigrain designs offer very narrow but limited zoom range field of views.
This is at the cost of obscuration of the secondary mirror. Note that there
are still refractive elements (lenses) in a casigrain design. This very narrow
fov is why such designs are prefered in telescopes and other narrow fov
application areas.

The majority of lens designs are refractive and this should give you an
indication that a statement such as mirrors are superior to refractive designs
simply is not true.

Edit - added application areas

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amrrs
An R package `rayshader` that can emulate bokeh. It's nice read.
[https://www.tylermw.com/portrait-mode-
data/](https://www.tylermw.com/portrait-mode-data/)

~~~
tylermw
Thanks for the shoutout!

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jonas21
If anyone's interested in the technical details of implementing state of the
art real-time bokeh in a game engine, Guillaume Abadie's "Life of a Bokeh"
slides from SIGGRAPH 2018 are really good:

[https://epicgames.ent.box.com/s/s86j70iamxvsuu6j35pilypficzn...](https://epicgames.ent.box.com/s/s86j70iamxvsuu6j35pilypficznec04)

Unfortunately, a video of the talk doesn't seem to be available online.

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pyridines
As a very nearsighted person, I can see bokeh if I take off my glasses and
look at points of light - either nearby small lights, or far-away large
lights. Also, when I look at a bright sky through a tree's canopy, the canopy
transforms into a breathtaking mosaic of bokeh, which becomes animated if the
tree is swaying in the wind. Can people with normal vision experience this?

~~~
gdubs
For me, points of light look like the canonical star shapes you see in
telescope photos — which I don’t really understand because from what I’ve
read, that effect is due to the braces which hold the telescope’s lens in
place.

~~~
arjie
That's called a 'starburst' and it happens in human eyes for all sorts of
reasons. It's possible naturally and also as a LASIK complication, for
instance.

Look for 'starburst' here
[https://visionsimulations.com/](https://visionsimulations.com/) Sadly the
simulation site is down because of the new Cross-Origin restrictions on images
in canvases but perhaps you can see what it looks like in the preview images
on the main page and if you google 'starburst vision'.

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StillBored
And its all done in software (or ML) with recent phones to get around the lack
of a good lenses system. And for most people it seems to work satisfactorily.

This has been one of the complaints against camera manufactures recently, that
the firmware on the cameras is wildly archaic.

~~~
penagwin
If we're talking about non-point and shoot cameras, such as DSLRs or
Mirrorless Cameras that cost $500+ such as my Sony A6000, I absolutely DO NOT
want post-processing done on my camera.

Portrait mode on my iPhone 7+ looks okay at a glance, but thinks like hair,
wires, and twigs are TERRIBLE on closer inspection.

Not to say the software couldn't be improved. For example, after taking a 20
second exposure, I have to wait another ~15 seconds before I can take another
photo. I'd love for that processing time to be cut down.

~~~
jiberius
The delay after taking long exposures is caused by the camera taking a dark
frame with the same exposure length as your actual image. When you take a long
exposure, the sensor can exhibit noise caused by "hot pixels". The dark frame
is taken with the shutter closed so that the camera can get an image of just
the hot pixel noise, which it then subtracts from your actual long exposure.

You can turn this off in the settings, but I imagine it's way easier for the
camera to correct for this specific kind of noise than for Lightroom to do so.

I believe it kicks in once the exposure length is >2" on my Sony A7ii.

~~~
tpolzer
On the one hand that's correct. On the other hand you could completely avoid
that if you did long exposures the way a Google Pixel (2+ I think) does it (in
software):

Take lots of short exposures and fuse them. If the device is handheld you get
variability in positioning for free, if it's on a tripod, it will
automatically wiggle the OIS slightly to achieve the same effect.

~~~
anamexis
It seems like movement would be effective for averaging out random noise, but
the described process isn’t for eliminating random noise, it’s for eliminating
persistent hotter pixels on the sensor.

~~~
IneffablePigeon
Indeed, and in fact the pixel does exactly the same dark frame trick to
identify hot pixels. I don't know that it takes as long though - perhaps it's
hidden by the fact you can keep doing other things while the photo is
processing.

~~~
tpolzer
It cannot do the same thing as an a6000, as it lacks a physical shutter.

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thyselius
Someone should mention the oval shaped, very cinematic, Anamorphic bokeh.
Bokeh is not just the shape of blurry small light sources, but also changes
the quality of any out of focus region, since the blur is doubled vertically
compared to horizontally. A good read on the subject with images
[https://www.provideocoalition.com/three-lenses-a-look-at-
bok...](https://www.provideocoalition.com/three-lenses-a-look-at-bokeh-depth-
of-field-and-geometry/)

~~~
twic
I cringe whenever i see that oval bokeh in a film. It's so jarring. I can't
believe a competent cinematographer would ever allow it in their shot.

~~~
crazygringo
Competent cinematography is about artistry and emotion, and whatever technical
standards are necessary to achieve that. And _everything_ with technical
issues about tradeoffs. Movies are _chock-full_ of tradeoffs.

Oval bokeh is... hardly noticeable to anyone except professional
photographers, and also isn't inherently "bad", it's just different, and has
its own personality.

If your standards are so perfectionist, I have a hard time believing you find
any of Hollywood's cinematographers -- whether blockbuster or indie -- up to
your competent standards. ;)

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michelpp
One of my favorite Bokeh lenses is the Nikon 500mm reflex telephoto lens. The
"Mak" style with a rear primary mirror and a front secondary works a lot like
common compact telescopes. The Bokeh is tricky to apply, it's a fixed zoom
telephoto lens so your subject must be at least 10 meters or so a way and it's
hard to handhold, but the "donut" aperture of the lens makes for some very
cool (or weird depending on your tastes) effects. The article calls this a
"bad" lens but I love the effect.

~~~
droitbutch
Your definition conflicts with the author's.

1st paragraph:

>as I own this site, I get to define good and bad Bokeh for the purposes here!
The other key term is “image.” Bokeh is a property of IMAGES, not a property
of LENSES.

~~~
droitbutch
not sure why I'm getting downvoted here for simply pointing out the author
defines his definition of Bokeh in the 1st paragraph.

~~~
asdfasgasdgasdg
I would guess that people think that the author's preferred definition doesn't
preclude other people from having different definitions. You seem to assume it
does, at least in the context of this discussion, and that assumption is
noxious to the people who are downvoting you.

~~~
abruzzi
I'd add that while the Author is correct--bokeh is a property of images, not
lenses--its not materially different that how most photographers understand
the term. While a lot of photographers may say things like "that lens has
great bokeh", they don't think that bokeh is some quality in the lens. They
are just shortening an idea lke "this lens produces images with great bokeh."
It is a lazy way of rephrasing it, but I have never met a photographer that
thinks bokeh is not referring to the image.

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murgindrag
Shape is important. I find that some lenses have a different look on-axis
versus off-axis, either leading to ugly smearing, or pretty twirly bokeh.

The aesthetic also depends on image. Nice crisp circles of light are sometimes
nicer than a Gaussian blur. As someone pointed out, mirror lenses have their
uses too.

But there are lenses with just bad bokeh too.

~~~
jake-low
> I find that some lenses have a different look on-axis versus off-axis,
> either leading to ugly smearing, or pretty twirly bokeh.

This is indeed pretty interesting. It seems like double-Gauss lens designs
like the Zeiss Planar and Biotar are especially prone to this kind of
distortion. There's a Russian copy of the 58mm Biotar called the Helios 44
that's popular on eBay for this reason (lots of people use an adapter to put
it on a MFT camera and shoot video with it).

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timw4mail
Lots of mirror lens bashing :(

Bokeh is subjective. While the rings instead of filled circles resulting from
a mirror lens look worse in many cases, I have seen cases where the 'rings'
actually add to the image.

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nimish
Isn't the airy disk the right PSF to use here?

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kseo3l
if bokeh gets to this point, I don't know how is it going to look in the
future. Is photography going to die

