DoF related to the camera angel

[Dschaga]

I always was wondering why cameras in a 3d software are so far away from reality. Most settings are crap and suggest me me that no1 in the dev team have a real SLR camera.

Let's start with DoF:
Sometimes you can see super wideangel renderings with amazing DoF and sometimes a tele which is sharp like a knife... both are wrong!

Wideangle (35mm-15mm) don't have a visible(!) strong DoF ..they can't since the focusplane is bend and the optic have to compense this behave. ..so everything which is unsharp is far away and we think it's sharp.

On the otherside, take a macro and try to focus an object... you will see that the image can become unsharp on the object you are focusing. ..the focusplane is flat and you will need a different f-stop to get a sharp image of the obect you are focusing. The difference to the wideangel is that the unsharp area is much closer ,so we think it have more DoF.

Both Images have the same DoF but we feel that the DoF on a Macro image is much stronger then on the Wideangel.


here is a page which describes what i mean:
http://www.luminous-landscape.com/tutorials/dof2.shtml




The camera in a 3d enviroment could be so easy, but we have dozens of settings for angel, DoF, Mobl ,colormapping/exposure...

you only need four parameters for a good camera:
1. exposure -> controlls the brightness of the rendering and Mobl.
2. f-stop -> DoF
3. focusing distance
4. lens

why not integrating a WORKING camera in Vray?

You could forget the DoF ,Mobl and the colormapping rollout on the renderpanel.

[egz]

I agree with you Dschaga. I'm a bit unsure if exposure should be tied that closely to time though, since you often need separate control over MB duration and the amount of light in the image. I'd like to see the naming of parts of the interface corrected to (like shutter size in DOF.. should be aperture size, or preferably F-stop). A few more lens types would be nice too. Like a proper wide angle lens that has the correct lens distortion. Trying to achieve that with the fisheye is not very easy.

I've discussed this with the developers a few times and I think there will be changes in the camera in a future version.

[egz]

I just noticed that the shutter size name has been fixed to aperture in the latest build

[egz]

Here's a quick mockup of how (or at least close to how, didn't spend ages on it) I'd like the camera rollout to look like:



I'd also love to see cameras like the brazilcam..

[Geddart]

Good topic - waiting for a more realistic camera too finally with bokeh.

Cool image egz, would love to see an interface like this in Vray. Really looks like a lot of control for me. We need some Min/Max Threshold controls for the mblur though - just one SubdivSpinner seems not enough. Some of these values could be integrated into a VrayCam Object too. Maybe this object could show as many parameters as possible directly in the Viewport. (like lens shape, focus plane and jitter preview of the dof in the viewport.) That would be really cool.
Btw is there already a renderer where you can define a Lens Curve via a custom Spline?

We see there are enough Features to add after the 1.5 Release.

[egz]

The motion blur controls are taken directly from one of the new builds, where using max/min isn't needed as far as I know. I agree that seeing the camera lens shape, focus plane etc. directly in the viewport would be great too. Just look at all the control you have with the Brazilcam.

As for renderers with lens curve control, I don't know of any renderers that have this built in, but PDI had lens curve control in the renderer they used for Shrek. http://www.flarg.com/bokeh_sketch.pdf

[vlado]

Re: DoF related to the camera angel

you only need four parameters for a good camera:
1. exposure -> controlls the brightness of the rendering and Mobl.
2. f-stop -> DoF
3. focusing distance
4. lens

Actually you need some more things - like the light sensor's response to exposure (which is what color mapping is trying to simulate) - for example, film and digital camera CCDs have different response to light. Further on, you may want to simulate not a photographic lens, but the way the human eye perceives the environment, which is somewhat different...

Best regards,
Vlado

[taboo]

Further on, you may want to simulate not a photographic lens, but the way the human eye perceives the environment, which is somewhat different...

hi vlado,
if what you said somehow possible and if you are planning to implement under vray, Vray will be a revolutionary software. maybe it is allready..

can you explain more how to simulate human eye (that is allways my dream in Cg) btw, i am talking about the fov and dof of the human eye.

thanks.

[Dschaga]

hey , that's nice that this topic doesn't died!

I just thought of something like a easy camera:


I don't want to fiddle around in the rendersettings when i want to change basic camera parameters.

There is a camera with a UI, which needs only few settings like above ...and then you have the renderer which should interpret the settings like samples of mobl,dof or the method of rendering -> two different dialogs!

The nice thing is that you can controll all effects like mobl and dof with the camera settings.

btw, the human eye works different then a camera, but to simulate it you will need a different Interface like a HUD which reacts fast to the movement of your eye(!).
I don't believe we will see it in the next ten years.

[egz]

Dschaga: I like this a lot, in fact Vlado had the same idea when we chatted about it earlier today. It would be great to have all the camera related settings in each camera. That way we can have different settings in the same scene.

The Camera rollout in the render dialogue should have an override checkbox though, which would make all the controls available there as well, just in case. As well as a system that lets you load/save settings and copy them from one camera to another.

[Dschaga]

some DOF samples:

this is a nikkor 105mm/f2.8 macro:
There is only a very smallarea of focus



this is a 50mm/f1.4:
..well somehow unsharp, but i think you can get the bigger area of focus (or not)



this is a 15mm/f3.5:
there is exactly NO dof effect and i can't archive such an effect with a 15mm!


link to bigger images

[Geddart]

Cool Thread
Good Suggestions - this is one of my After 1.5 Feature Wishes!
Hope we'll see a smart VrayCam Solution with enough control in an intuitive ui.