[Bf-committers] DOF camera parameters.

Campbell Barton bf-committers@blender.org
Thu, 10 Jun 2004 19:21:44 +1000

About implimenting DOF in blenders renderer-

This could be done the same way as motion blur
rendering the same image from different positions and then mixing them.

This can alredy be done with ipo's and motion blur.
but with these settings it could be done automaticly.

Also- an autofocus system would be cool too.

 - Cam

Matt Ebb wrote:

> On 10 Jun 2004, at 5:33 PM, Jonathan Merritt wrote:
>> As part of the Aqsis RenderMan exporter that I've been hard at work 
>> on over the last two weeks, I've added some new parameters to the 
>> Blender camera:
>>    1. Focal length ("internal" camera parameter).
>>    2. Focal distance (distance to point of perfect focus).
>>    3. f-stop (traditional photographic measure of the aperture size).
>> These parameters truly "belong" to the camera, rather than to the 
>> scene or exporter settings.  This is because it makes sense for 
>> different cameras to have different settings, and for the settings to 
>> be animated with the camera itself.
> Interesting! Am I right to assume that these parameters are 
> Aqsis-specific? As in, they have no utility when rendering from within 
> Blender, and would only be shown when Aqsis is selected as a renderer?
>> In the Aqsis CVS version of Tuhopuu, these camera parameters are 
>> completely finished, hooked up to IPOs, etc.  Here's a screenshot 
>> showing them in action:
>>    http://www.warpax.com/temp/screenshot-new-camera.png
>> Given that it's all set up for people to play with, I have a few 
>> questions.  These are probably best answered by those who are the 
>> true "custodians" of Blender (probably most of whom are active on 
>> this list):
>>    1. Are there any changes I should make?
>>    2. I'd like to display focal distance (the distance to the point 
>> of perfect focus) in the scene.  Currently, I do this with a simple 
>> cross along a line from the camera, which is displayed when 
>> "ShowLimits" is selected.  Should this display be improved?  Should 
>> it perhaps include some indication of the depth of field: ie, some 
>> kind of "in focus range", over which the focal blur is always within 
>> some arbitrary value?  Any ideas (or mockups) for how this should look?
> The first thing that personally comes to mind for showing the in-focus 
> area is using 3 circles, as a kind of metaphor for the circles of 
> confusion in the DOF effect - 
> http://mke3.net:9000/blender/ui/controls/camera_circ_conf.png
> Definition of circles of confusion for non-photography types: 
> http://www.tpub.com/content/photography/14209/css/14209_38.htm
>> PS -
>> Q: Why do we need "FocalLen" when "Lens" apparently contains the same 
>> information?
>> A: Lens in Blender controls the angular field-of-view of the camera, 
>> whereas FocalLen is the camera focal length expressed in Blender 
>> scene units.  The alternative to this scheme would be to use the Lens 
>> setting in combination with a less-intuitive scale factor to find the 
>> focal length in scene units.  I thought it was best to separate these 
>> two so that the settings were available in the most straightforward 
>> fashion.
> Would the 'FocalLen' operate independently of Blender's 'Lens', or 
> would changing the 'FocalLen' actually change the zoom when looking 
> through the camera? If so, this seems a little confusing to me, having 
> two controls that change the same property, but with different scaling.
> Cheers
> Matt

Campbell J Barton

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