hi

I build a camera in the scene and I want to make the camera keeping the scale to the screen when i zoom the scene, how to realize it?

thanks.

You want the objects in the scene to maintain their scale when the camera zooms in? Is that what you are trying to achieve?So objects wouldnt look bigger?Sorry just trying to understand what you are trying to say

yeah… it sounds like you're trying to do the Hitchcock effect? Zoom out while trucking in?

it's called a Dolly Zoom….
http://en.wikipedia.org/wiki/Dolly_zoom [en.wikipedia.org]

hehe~…sorry,my english is poor

the objects that maintain their scale is just camera objects when look the scene through any view such as perspective view.
For example,in 3dsmax or maya ,every camera or light has an icon ,their icons is maintain their scale when the view is zoomed out or in(what i expressed is correct??) ,.but in houdini , a geometry is substitue, I just hope it wouldn't look too small to find it
can you understand what i said??