It has taken me a while to dig up the specific intentionally used background I've used occasionally, so that I could share a simple idea with you; as for the most part I use whatever nature has available. However, below are three examples of photography using a frosted window pane, facing North, natural light, done on a tripod with my Nikon D90 camera. The effects are all different depending on the type of light provided from the outside. Of course no flash is used. On these photos the settings were set on automatic, as the camera has a pretty good synchronization. The backgrounds seem to have picked up the reflections of the greenery on the outside of the house. The first one of the fern was done in winter, with no greenery in bloom on the outside of the glass. The 2nd was on a cloudy day, and the 3rd has reflections of greenery from the outside. Same window, different effects. So a simple frosted window pane can serve as a good backdrop.
