<p>A rather down-to-earth solution - but more controllable than a lens with flare:<br />When in difficulty without adequate fill, I lay a white card inside on the floor of the bellows. The card catches some extraneous light from above the scene and pre-flashes in proportion to the exposure. Been doing it for a long time with Ektachrome and such - there’s no need with B&W because development takes care of shadow detail.</p>