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aspect ration of camera cones


Bartjuan

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Whats happening here?

if I set up 3 identical views (3 point persp)

and set views to visible

then change the focal length of 2 of the views, the aspect ratio of the field of view indicator changes.

 

 

I would love to manually set the aspect ratio of the field of view indicator to match a specific standard ( like in "image Options") or keep it square at a minimum.

 

if there is a logic I am missing here let me know

 

Bart

post-225-0-46026600-1445618237_thumb.jpg

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Hi Bart,

 

The aspect ratio is determined by the Display menu: Image Options settings.  When you save a view, whatever is in that view will be retained in the final view.  If you make the Image Options taller but don't change the width, the view will be "un-cropped" and you will see exactly the same thing but more of the top and bottom of the scene.

 

Does that answer  your question?

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No, Sorry, 

 

I'm talking about the pyramid shape that represents the cameras cone of vision, I believe it is called a frustum.

 

it makes sense to me that if I change the lens on a camera the viewing "cone" changes.

 

but if I have three identical cameras, and all I change is the lens ( focal length in FZ) from 75mm to 35 mm to 28mm

 

why does the frustum go from wide rectangle, to square, to tall rectangle?

 

see the attachement on original post

 

( sorry for the double post, glitch during posting)

 

Bart

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Hi Bart,

 

The proportions come from the Window Size.  Here is what I get if I save 3 views, and adjust their Focal Lengths as you describe:

 

post-5-0-03460400-1445635935_thumb.jpg

 

The first two are the same because I started with the middle cone, the inner cone just expanded the view, but the larger cone was adjusted to fit the window proportions...

 

Does that help?

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ok, I definitely have some strange anomaly happening.

 

here is what I am getting by creating a view, making 2 copies and changing the focal distance: image ratio2.jpg

 

the red rectangle is the frustum for a view with a focal distance of 28mm. there is a inner rectangle that is wider than tall that is the 75mm focal distance.

 

What is really odd is that if I now change the 28mm view to 29mm it snaps back to almost square.

 

Same with the wide 75mm view, if I change it to 74 or 76 it snaps back to square..

 

 

- if I change it a lot (to a lower number) the frustum gets narrow and tall.

if I change it a lot ( to a highr number) it gets wide and short 

increment a tiny bit 9 up or down) and it gets close to square.

 

image ratio3.jpg shows what I am seeing, 

on left is camera, focal distance adjusted   down from 35 to 28

on right is camera, focal distance adjustred  up from 35 to 75

 

post-225-0-56315700-1445637502_thumb.jpg

post-225-0-65185600-1445637983_thumb.jpg

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