You are quite right. It may cause discomfort. :-)

I had a bit of eye strain yesterday. So I will give it a rest today.

On 26/10/2014 07:05, clipka wrote:
> Am 24.10.2014 22:16, schrieb Stephen:
>> On 24/10/2014 20:37, Le_Forgeron wrote:

>> Indeed! and what effect does increasing the distance have?* Some of my
>> reading suggests that for distance shots an extended baseline is
>> recommended.
>
> I consider that recommendation nonsense: Yes, long-distance shots with
> standard eye distance are problematic for 3D because they provide little
> to no 3D effect at all.
>
> However, increasing the eye distance has exactly one primary effect: It
> makes the scene appear smaller. (Likewise, decreasing the eye distance
> makes it appear larger.)
>
>

I have two options.
Experiment with a simpler scene. Or make my mind up which scale to use. 
Whether it is the internal scale of the scene or the scale of the 
external viewer. (I think the answer is in the option)



>>> * where is the focus point where both centres of picture's rays meet.
>>
>> Again, is there a recognised behaviour when you change that point?*
>
> My recommendation would be to put the focal point at a distance
> equivalent to the expected viewing distance to the screen.
>

Bingo! Thanks. A flash of insight there.

> Changing that point won't mean a thing to the 3D effect, but may cause
> discomfort.
>
>
It does, on some of my tests I noticed eye strain when focusing on 
different parts of the scene.

> There's one other very important thing to consider though: Camera angle.
> For best results, the camera angle should be the same as the expected
> "screen angle" in real life. Any other than that, and you'll introduce
> distortions that may cause discomfort.
>
>
> All in all, the camera parameters should match the expected viewing
> situation as closely as possible, with the display corresponding to the
> look_at plane.
>
>
I think I have it now. I have been using the wrong viewpoint.

> Obviously, following this advice is not practical, because it severely
> limits your choice of camera perspective :-P - but it should give you a
> sound starting point.
>

If only the "Mind's Eye" camera could be developed. ;-)


>
> With LCD shutter glasses, the question is irrelevant, as it applies only
> to side-by-side viewing.
>
I thought it might.

>
>> The articles I've read talk about a lens's near and far points depending
>> on the focal length of the lens. Which in itself gives an estimate for
>> the angle of view.
>> That is not pinhole camera stuff. (I hope)
>
> Stick to the pinhole stuff, it is actually a better fit to the viewing
> situation (presuming you don't have one of those fancy new curved panels).
>

I will and I don't.

-- 

Regards
     Stephen

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