Hi,

While I'm playing with the angle of the camera (see p.g), I was
thinking: What is the difference between a small angle and placing the
camera closer?
I'm using the standard camera.

Remco Poelstra

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Remco Poelstra wrote:
> 
> Hi,
> 
> While I'm playing with the angle of the camera (see p.g), I was
> thinking: What is the difference between a small angle and placing the
> camera closer?
> I'm using the standard camera.
> 
> Remco Poelstra

That's a matter of perspective, as with a normal photo-camera,
perspective changes , when you change the focal distance/angle.  The
extreme case is an orthographic camera, when all parallel lines in the
scene are parallel on the image too.  

You should try the effect using a simple scene with rectangular shapes
in different distances.

HTH, Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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Remco Poelstra wrote:

>Hi,
>
>While I'm playing with the angle of the camera (see p.g), I was
>thinking: What is the difference between a small angle and placing the
>camera closer?
>I'm using the standard camera.
>
>Remco Poelstra
>

The perspective.
The perspective is determined by the distance camera to object, not the 
viewing angle.
Try this, make a box -1,1 and rotate it y*45, put the camera at a certain 
distance on -z, use a small view angle. Trace the image with a size of 
320x240.

Now change the the angle to a bigger value. Trace the image a such a size 
that the hight of the box, in pixels, is the same as in the first picture. 
Cut out the 320x240 area around the box and save as a new picture.

Third picture is renderd at 320x240 again. For this one keep the angle, 
but move the camera so much closer to the box that the height, in pixels, 
is the same as in the previous pictures.

When you compare the three pictures, yo'll se that No1 & No2 are the same. 
In No3 the angles of the box seem to be sharper, change of perspective.

So, the perspective is determined by the camera to object distance. The 
angle of view is used to "zoom in/out" on the object/scene.



Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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I think you can see the effect of moving the camera and changing the camera
angle/direction in the IRTC "Pool Shark" anim (zooms while not zooming on
the angry big guy). IIRC that is.


Povingly


Philippe

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Philippe Debar wrote:

>I think you can see the effect of moving the camera and changing the
>camera angle/direction in the IRTC "Pool Shark" anim (zooms while not
>zooming on the angry big guy). IIRC that is.

Yes, the vertigo shot. Named after Hitchcock's Vertigo (1958) where it is 
used in perfection. Doing it with a real camera is one of the most 
difficult things. All depends on the skills and coordination of the dolly 
pusher and the focus puller.

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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ingo wrote:
> 
> Philippe Debar wrote:
> 
> >I think you can see the effect of moving the camera and changing the
> >camera angle/direction in the IRTC "Pool Shark" anim (zooms while not
> >zooming on the angry big guy). IIRC that is.
> 
> Yes, the vertigo shot. Named after Hitchcock's Vertigo (1958) where it is
> used in perfection. Doing it with a real camera is one of the most
> difficult things. All depends on the skills and coordination of the dolly
> pusher and the focus puller.
> 

I really don't see it. Can you say at what frame it starts?

Remco Poelstra

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Remco Poelstra wrote:

>I really don't see it. Can you say at what frame it starts?
>

No player here that shows the frame numbers. But the sequence starts just 
after the white ball falls in the glass. The head of the other player is 
first getting "thinner", then the camera moves towards him and you see 
stars. The getting "thinner" part is what it is about.

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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ingo wrote:

>Remco Poelstra wrote:
>
>>I really don't see it. Can you say at what frame it starts?
>>
>
>No player here that shows the frame numbers.


From the source of poolshark:

  #case (7) //--------------- Shot 7 ------------------------------

  // Frames 456 - 500 (1.5 sec.), clock from 0 to 1
  // Player looks shocked, camera moves in and zooms out.


Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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ingo wrote:
> 
> Remco Poelstra wrote:
> 
> >I really don't see it. Can you say at what frame it starts?
> >
> 
> No player here that shows the frame numbers. But the sequence starts just
> after the white ball falls in the glass. The head of the other player is
> first getting "thinner", then the camera moves towards him and you see
> stars. The getting "thinner" part is what it is about.
> 

I've got it. The viewing angle becomes bigger, while the camera is
standing, right eh?


I've done your "experiment". I've never thought that setting up a good
camera is so important. I personnaly like the more distant camera. (the
box looks like more a box).
Are there some tutorials about placing, setting the camera?

Remco Poelstra

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In article <3952C9FD.FFDE370A@home.nl>, Remco Poelstra 
<rjp### [at] homenl> wrote:

> I've done your "experiment". I've never thought that setting up a good
> camera is so important. I personnaly like the more distant camera. (the
> box looks like more a box).

A wide angle and close camera can often help to make something appear 
very large, something that can be difficult to accomplish otherwise.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
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