Camera.orthographicSize
var orthographicSize: float;
float orthographicSize;
orthographicSize as float
Description

Camera's half-size when in orthographic mode.

This is half of the vertical size of the viewing volume. Horizontal viewing size varies depending on viewport's aspect ratio. Orthographic size is ignored when camera is not orthographic (see orthographic). See Also: camera component.
	// Set the camera's ortho size to 5

camera.orthographic = true; camera.orthographicSize = 5;
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        camera.orthographic = true;
        camera.orthographicSize = 5;
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		camera.orthographic = true
		camera.orthographicSize = 5

Using specifically the main camera:
	// Set the main camera's ortho size to 5

Camera.main.orthographic = true; Camera.main.orthographicSize = 5;
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        Camera.main.orthographic = true;
        Camera.main.orthographicSize = 5;
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		Camera.main.orthographic = true
		Camera.main.orthographicSize = 5