Indigo aperture diffraction vs real life - too weak

General questions about Indigo, the scene format, rendering etc...
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CoolColJ
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Indigo aperture diffraction vs real life - too weak

Post by CoolColJ » Mon Jun 25, 2012 6:19 pm

I think Indigo's simulation physical aperture diffraction is very weak compared to real life, at the same fstop settings. I usually need to go over F64 to get results like these!

me thinks the simulation needs tweaking :wink:

Image

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Pibuz
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Re: Indigo aperture diffraction vs real life - too weak

Post by Pibuz » Mon Jun 25, 2012 7:18 pm

I've seen that too, even in a much less techical way :lol:

I fear I have to add a +1 to CoolColJ request of tweaking

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galinette
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Re: Indigo aperture diffraction vs real life - too weak

Post by galinette » Fri Jun 29, 2012 7:54 pm

Which camera did you use for your photographs?

Etienne
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CoolColJ
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Re: Indigo aperture diffraction vs real life - too weak

Post by CoolColJ » Fri Jun 29, 2012 8:16 pm

galinette wrote:Which camera did you use for your photographs?

Etienne
I didn't take them :wink:

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galinette
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Re: Indigo aperture diffraction vs real life - too weak

Post by galinette » Sat Jun 30, 2012 12:58 am

Ah OK...

Just wanted to check the sensor size : by using smaller sensor (and by scaling accordingly the focal length for constant FOV) you will increase diffraction. The theory says that at same aperture f Number, a small compact camera with a small sensor will suffer much more from diffraction than a FullFrame SLR (and Indigo should take it into account)

You will also increase DOF by doing this, but that's also like this in the real camera world.

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Zom-B
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Re: Indigo aperture diffraction vs real life - too weak

Post by Zom-B » Sat Jun 30, 2012 1:43 am

I posted it in CoolColJ's test pics Thread, but for since its better fitting in here:
Zom-B wrote:
CoolColJ wrote:real camera have way more diffraction at the same fstop as Indigo - me thinks the simulation needs tweaking :wink:
Maybe that (sadly still not released) Paper could be a good starting point:
Polynomial Optics: A Construction Kit for Efficient Ray-Tracing of Lens Systems
polygonmanufaktur.de

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OnoSendai
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Re: Indigo aperture diffraction vs real life - too weak

Post by OnoSendai » Sat Sep 01, 2012 5:39 am

Hi All,
Etienne is correct as usual, the photos themselves can't tell us anything exact when we don't know the actual aperture size. We also don't know how much the photos have been cropped.

Having said that, Indigo was definitely cropping/clipping the edge of the diffraction pattern too much.

There is a trade off between memory use and computation time and maximum possible width of the diffraction pattern. I've increased the diffraction resolution a little to reduce the clipping.

Here's the sun at f/22 rendered with the new code:
Attachments
sun_glare_test f22.jpg

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CoolColJ
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Re: Indigo aperture diffraction vs real life - too weak

Post by CoolColJ » Sat Sep 01, 2012 7:11 am

I meant the physical diffraction, has this been improved as well?

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OnoSendai
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Re: Indigo aperture diffraction vs real life - too weak

Post by OnoSendai » Sat Sep 01, 2012 8:03 am

Hi CCJ,
what do you mean by physical diffraction? Non-post-pro?
Because they're both as physical as each other :)

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CoolColJ
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Re: Indigo aperture diffraction vs real life - too weak

Post by CoolColJ » Sat Sep 01, 2012 10:50 am

OnoSendai wrote:Hi CCJ,
what do you mean by physical diffraction? Non-post-pro?
Because they're both as physical as each other :)

Yes the one that is enabled whilst rendering

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Zom-B
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Re: Indigo aperture diffraction vs real life - too weak

Post by Zom-B » Sat Sep 01, 2012 3:09 pm

great stuff Ono, maye rendering the same sun with the "old" 3.4.6 code could show us the enhancement :)
Since we are at the topic, I asked my self why the internal AD generates that color noise...
That brought me to some technique to generate chromatic aberration with colored aperture image, like in the picture here:
bokeh_001[1].jpg
polygonmanufaktur.de

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Re: Indigo aperture diffraction vs real life - too weak

Post by StompinTom » Sun Sep 02, 2012 3:29 am

Zom-B wrote:great stuff Ono, maye rendering the same sun with the "old" 3.4.6 code could show us the enhancement :)
Since we are at the topic, I asked my self why the internal AD generates that color noise...
That brought me to some technique to generate chromatic aberration with colored aperture image, like in the picture here:
bokeh_001[1].jpg
Brilliant!

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