How to render frame by frame?

I have a animated camera which has 70 frames. I need to save images of exactly 70 frames of the camera into png files.
So in a way it has to be CPU-speed independent. Is it even possible to tell unity don’t go to the next frame unless I tell you so, so that I make sure I’m not having missed frames?

You can try to capture the screen in the OnRenderImage function. I suggest you to look at the MonoBehaviour functions.
Here is also an interesting topic: Efficiently capturing rendered images ?

And here you can try setting your framerate using Application.targetFrameRate.