A few days ago, i've problem with camera and path animation. When i want create on scene with 3 camera and 3 curve for camera path animation. The problem is how to moving every camera with different starting frame? Because for default every camera will be start at first frame. I don't know how to explain what i want. It's just simple ilustration for camera what i want.

I hope you understand with my illustration above. 

For problem like me don't using offset and other, its really dont help us! It make us confuse. And my friend give me great solution like here:

• Add a follow path constraint to every camera and set the path. ex: cam_01 with curve_01.
• Selection the curve > object data > path animation.
• Frames mean how long this must spend from starting point to end point. Evaluation time mean where is place of the object. I just little confuse to explain that. I'll give example, i hope you understand
• Like my problem above, i want cam_02 start following curve_02 at frame 20 until 40. So you get the duration from start point to end point of curve. It's 20frames. So you need set Frames at path animation to 20.
• Now go to frame 20. On frame 20 you have 0.00 Evaluation Time. Insert keyframe on this. Just press i button over the icon, and the color will be changed.
• And go to frame 40. On frame 40, change the Evaluation Time to 20, because long of the curve is 20frame. So the camera will be moving into end point of curve. Insert keyframe again like before step.