chromatic aberration in Corona

[piotrus3333]

I've been rendering some tests lately regarding feasibility of creating that sort of effects in render without any kind of post. render, save it, done.
anybody have experience with that in Corona? (not colored aperture maps - I need something realistic)

question: any chance of setting IOR below 1? when I'm inputting it as color - value of 0.9 gives me IOR 1.1

[maru]

I can only think of some crazy workarounds like putting a plane with refractive material with dispersion enabled in front of the camera. :)
But it needs some IOR then, 1.0 won't work.

As to your IOR question - I think you should plug a Corona Color map into your IOR, set it to pure white, and then adjust the output multiplier value.

[romullus]

question: any chance of setting IOR below 1? when I'm inputting it as color - value of 0.9 gives me IOR 1.1

IOR<1 are treated as 1/IOR in Corona, so you're getting correct result.

[piotrus3333]

IOR<1 are treated as 1/IOR in Corona, so you're getting correct result.

to optimize this setup I would actually need "incorrect" IOR<1.
but no worries - nothing essential.

[sbrusse]

Any news for this?
I'd love to have the ability to plug "real" type of camera in corona.
If you look at all the data that we can find in PS or lightroom with build in lens corrections that distort the real cams to get more "accurate" results,
Would be great to be able to replicate those improper camera types (vignette, CC, distortion, etc) as presets like LUTs.
DXO has a freaking list of data as well.
Would be completely awesome to get this embedded inside Corona.

Does this make sense?
Stan

[piotrus3333]

I'd love to have the ability to plug "real" type of camera in corona

I guess all the tools are already there.
not a lot of work to prepare distortion texture and adjust vignette.

[BigAl3D]

Not sure if this has been mentioned, and I assume it will translate to other 3D apps and not just C4D, but this tutorial from Brograph shows a super simple method for achieving realistic aberration FX.

[piotrus3333]

Why would you want to couple color aberration with distortion? distortion has separate dedicated tools in probably every virtual camera in every package.
flat "lens" with dispersion is enough.

[romullus]

Flat lense probably wouldn't give you any abberations, but even if it would do, CA would be evenly large across all the image. Anyway, that method is just an interesting hack and hardly could be considered as practical substitute for post-effect CA. I will wait for proper CA implementation from Corona Team. Somehow i believe, it won't take too long :]

[piotrus3333]

my examples from first post were done with flat lens. some even with single polygon lens (single polygon unfortunately not in corona).
agree on the level of usefulness though.

[BigAl3D]

As far as doing this effect in post, unless you render out a pass for that (depth?), it's not a true 3D effect.

The irony is you want to use good enough lenses when filming to avoid aberrations, but in 3D, we add them in to make it look more like a real-world cheap lens. Same thing with camera movement, bobs, bumps, etc.

Whatever gets the job done.

[pokoy]

The irony is you want to use good enough lenses when filming to avoid aberrations, but in 3D, we add them in to make it look more like a real-world cheap lens. Same thing with camera movement, bobs, bumps, etc.

How true! The worst thing about CA is that if you give it to a printing shop they'll think their plates are misaligned. If they find out it's intentional they'll probably lose any faith in humanity.

Seriously, CA is mostly way overdone in CG. You won't see it unless you have extreme FOV (or a very bad lens), and a high res image and zoom in at 300% close to the image border. It's really a subtle effect and introducing it at resolutions below 3K is almost always wrong.

[romullus]

As far as doing this effect in post, unless you render out a pass for that (depth?), it's not a true 3D effect.

I don't think that CA very dimensional effect in real world too. It happens in a lens and doesn't depend on a scene. As long as you shoot with the same lens with the same settings, all pictures will have the same amount of CA, no matter the subject.

[burnin]

^ oh so true
because it's glass dependent - the combination of glasses (form & material) in lenses makes it

& why every lens create slightly different aberration
thus even simulations are approximations to some extent

with skill you become an artist ;)

[pixel-flow]

I recommend VFB+
http://www.monotoneminimal.com/vfb
It's completly free