Another lens test

[suvakas]

Is it normal that it's flipped like that? The reality isn't flipped with real camera.
Why is that happening here?

[ryjo]

It's reversed because the indigo camera is taking a photo of a projected image and not of the objects them selves (which is what a camera normally do).

This is like being inside a camera obscura and taking a photo of the projected image.

[Kram1032]

doule-projected

[suvakas]

Gotcha! Of course..stupid me..
Thanks.

[mrCarnivore]

So the model of a lense actually works the same as the indigo Thin lens model. Without the lens, the render is just much faster...

Did you want to show this? Or was the point something else?

[StompinTom]

right well now we can start fucking around with actual lenses, not just a Thin lens model. say a fisheye lens or even a tilt-shift lens. thats whats cool about it.

[OnoSendai]

Plus you can simulate lens flares

[StompinTom]

and when we can start simulating lens coatings, things will get really interesting.

[Kram1032]

lens coatings?
Really nice thread!

[suvakas]

I'm currently testing the lens model and I can't get it to focus no mather what i do. Any more tips ryjo ?
If the object is closer to the lens, then i have to move the white plane closer to Indigo camera? I went almost all the way to indigo cam, but no changes in output image.
Also, what's that big tube thing that covers all objects? Is that necessary? I'm only using black box, lenses and white plane. Do i miss something? What's that huge tube for?

[edit]:
Ok. I got it focused, but the rendering is not from model i have the lens pointed to. It is focused to the background and no sign of my models. That is really strange, cause my models are right infront of the lens. Help!!! ..Eh.. this is real fun (with real lens)
Anyway.. i get that this is all trial and error, but maybe you have some tips ryjo?

[ryjo]

I'm currently testing the lens model and I can't get it to focus no mather what i do. Any more tips ryjo ?
If the object is closer to the lens, then i have to move the white plane closer to Indigo camera? I went almost all the way to indigo cam, but no changes in output image.
Also, what's that big tube thing that covers all objects? Is that necessary? I'm only using black box, lenses and white plane. Do i miss something? What's that huge tube for?

edit: The screen should be moved further away from the lens when objects are close to the lens!

Oh, the tube... remove that it's no longer part of the system. The following obj files are used:
e1.obj -- front lens
e2.obj -- middle lens
e3.obj -- back lens
a.obj -- aperture (six-bladed) (optional)
b.obj -- box sides
c.obj -- casing for objective lens, outside box
f.obj -- front of box, lens opening
s.obj -- screen, back of box

a, b, c and f should be black.
s should be white.
e1-e3 must have these materials:

Code: Select all

	<medium>
		<name>glass_ior_1_623</name>
		<basic>
			<ior>1.623</ior>
			<cauchy_b_coeff>0.0</cauchy_b_coeff>
			<absorption_coefficient_spectrum>
				<uniform>
					<value>0</value>
				</uniform>
			</absorption_coefficient_spectrum>
		</basic>
	</medium>

	<medium>
		<name>glass_ior_1_624</name>
		<basic>
			<ior>1.624</ior>
			<cauchy_b_coeff>0.0</cauchy_b_coeff>
			<absorption_coefficient_spectrum>
				<uniform>
					<value>0</value>
				</uniform>
			</absorption_coefficient_spectrum>
		</basic>
	</medium>

	<material>
		<name>e1mtl</name>
		<specular>
			<transparent>true</transparent>
			<internal_medium_name>glass_ior_1_623</internal_medium_name>
		</specular>
	</material>

	<material>
		<name>e2mtl</name>
		<specular>
			<transparent>true</transparent>
			<internal_medium_name>glass_ior_1_624</internal_medium_name>
		</specular>
	</material>

	<material>
		<name>e3mtl</name>
		<specular>
			<transparent>true</transparent>
			<internal_medium_name>glass_ior_1_623</internal_medium_name>
		</specular>
	</material>

Don't put the object too close to the camera, or it may not be able to focus, no matter how much you move the screen.

The screen must be moved by 1.5 mm closer to the front to focus at infinity, and the a little closer for objects closer than that.

edit: The screen should be moved further away from the lens when objects are close to the lens!

For the indigo camera, use a small aperture setting (like 0.00001) and <autofocus/>.

hth [/u]

[mrCarnivore]

The screen must be moved by 1.5 mm closer to the front to focus at infinity, and the a little closer for objects closer than that.

Why did you put the screen in that position then if its not focussed on anything there? Or is it focussing on everything that is even further than infinitely away?

[suvakas]

Thanks for the info! Yes, i thought that the tube is not useful. I got black image when i used it.
Ok. I will do some more testing with the scene.
It's quite fun to play.

[ryjo]

The screen must be moved by 1.5 mm closer to the front to focus at infinity, and the a little closer for objects closer than that.

Why did you put the screen in that position then if its not focussed on anything there? Or is it focussing on everything that is even further than infinitely away?

In theory the lens is 50 mm, which means that the screen should be at 50 mm when focusing at infinity. But the modelling was not perfect so when trying the lens i realized that the screen should be at 48.5 mm instead. It was just easier to make the change in the xml file (using 'pos') than re-exporting it.

[ryjo]

I was wrong about the movement of the screen: If objects are closer to the camera than infinity then move the screen away from the lens.

So objects @ infinity -> screen @ 48.5 mm
... objects @ 5 m -> screen @ 50 mm (perhaps, i don't know exactly)