camera.Render() does not work in editor

I am trying to control when the camera renders to achieve an effect. Firstly, I disable the automatic rendering with camera.enable = false, then in the Update() I call camera.Render() it only displays a grey screen in the game view window, however the built application renders fine.

My goal is to render once with a small far clipping plane, then render with increased near and far planes (without clearing the depth buffer).

Am I missing a editor flag? I have tried using [ExecuteInEditMode]. Building the application each time is a huge waste of time.

Screenshots of scene view:

Screenshots of game view vs built application: