fish eye cityscape

dougal2 · Post by **dougal2** » Wed Mar 28, 2007 11:14 am

this is the scene that has evolved from my fisheye/sunset experiments.

I'm not sure yet how detailed I want to go with the city buildings, but from this render you can see what I'm getting at.

I've also done a bit of post-pro on this, to colour correct it, remove the sun (which looked ugly), and soften the lens flares.

Also, my lens has a defect in the centre, which made a little dent in the middle buildings, i've corrected that too in post.

DaveC · Post by **DaveC** » Wed Mar 28, 2007 11:32 am

I'd love to see that before you did the post-pro. With the sun and full-on lens flares. Great job

manitwo · Post by **manitwo** » Wed Mar 28, 2007 9:48 pm

great experiment!

suvakas · Post by **suvakas** » Wed Mar 28, 2007 9:53 pm

Yes, show the flares, show the flares

dougal2 · Post by **dougal2** » Wed Mar 28, 2007 10:16 pm

here's the raw render

suvakas · Post by **suvakas** » Wed Mar 28, 2007 10:27 pm

hmm..those flares are kind of dissapointing. I was hoping like.. i don't know.. reality. But that's cool.

mrCarnivore · Post by **mrCarnivore** » Wed Mar 28, 2007 11:04 pm

Isn't in reality the most amount of flare visible when the sun is JUST out of the visible area?

Kram1032 · Post by **Kram1032** » Wed Mar 28, 2007 11:59 pm

yes, I guess so, 'cause, if the sun is in your sight, it will be too bright to see the flares...
Maybe, you can let the camera point exactly on the sun, but model a tiny circle in front of it... -> sun disappears, halos get stronger...

mrCarnivore · Post by **mrCarnivore** » Thu Mar 29, 2007 12:16 am

No, the sun has to be visible but not in the field of view!

So tilt the camera so the the sun is just out of the field of view. Maybe I will try this when I'm home tonight...

dougal2 · Post by **dougal2** » Thu Mar 29, 2007 9:58 am

i've done a little more experimenting, trying to discover exactly why each lens element is necessary.

it turns out that #4 has the defect that makes the little "bubble" in the middle, and since it only contributes minimal magnification to the overall image, I shall now be excluding it.

here are some other combinations I tried:
(the main, current render, is without #4 and just zoomed in a little. I've also sunk the sun to just below the horizon).

mrCarnivore · Post by **mrCarnivore** » Thu Mar 29, 2007 9:26 pm

I can hardly imagine that they include a lens that has almost no effect...

After all every lens that is added decreases the amount of light that is passed through and increases the price.

Having said that, there might be a need for this lens in real life that is not needed in indigo e.g. for colour correction purposes. Maybe if you added the correct cauchy_coeff to each lens you would see the effect the lens has...

8bstudio · Post by **8bstudio** » Thu Mar 29, 2007 9:33 pm

Very good idea!

dougal2 · Post by **dougal2** » Thu Mar 29, 2007 9:38 pm

mrCarnivore wrote:I can hardly imagine that they include a lens that has almost no effect...

After all every lens that is added decreases the amount of light that is passed through and increases the price.

Having said that, there might be a need for this lens in real life that is not needed in indigo e.g. for colour correction purposes. Maybe if you added the correct cauchy_coeff to each lens you would see the effect the lens has...

there is actually a very big difference between this lens in real life and in indigo.

In real life the lens if used to focus an image onto a screen, which may either be the film, or a "focussing screen" that you look at (and your eye focusses to independantly).
I cannot get this method to work in indigo. Probably something to do with discovering the correct screen material (diffuse white doesn't work, very high exponent phong/specular doesn't work).

What I am actually doing is pointing the camera through the lens, similar to as if you held the real lens to your eye. Now, becuase of the (auto?)focal abilities of your eye and the indigo camera, the light rays passing through the lens no longer need to be focussed onto a plane (??correct me if I'm wrong here...), hence omitting lens elements doesn't affect the image focus, although it does affect the magnification/distortion of the lens system.

So... any ideas on sreen materials and how to make it work?

Post by **OnoSendai** » Thu Mar 29, 2007 9:49 pm

It should work fine if:

* your sensor/screen material is diffuse white (1,1,1)
* you position the indigo camera inside ur camera model
* point the indigo camera in the opposite direction to the fisheye camera
* set the focal distance of the indigo camera to the distance beteeen the indigo camera location and the fisheye sensor/screen

mrCarnivore · Post by **mrCarnivore** » Thu Mar 29, 2007 11:23 pm

@dougal2: You are right. I didn't think about focussing.

Might be interesting to see how it look when using Onos tips...