nature B-roll for documentary film

[HKB]

Does anyone have any guidelines on how to arrange nature B-roll shots? Mainly looking for the do's and don't's.
Basically, I'm shooting a variety of shots of wide angle marshy areas and close ups of reflected light on water with
tree branches blowing in the foreground, close ups of blowing marsh grasses and so on. I recall an accomplished
professor in film school that was critiquing some similar B-roll and saying, that scene doesn't work with that scene
and so forth. I didn't understand what he was talking about because I never took the class where he taught these
techniques. Was wondering if anyone could point me in the right direction.

 

[Razz16mm]

Take it from an old news hound and documentary shooter. B-roll is not just random pretty shots of anything that piques your interest. B-roll shots should be chosen to enhance the flow of the story. A couple of examples:

POV: point of view. Your A-roll for example might be an interview of a person sitting on his porch looking out at the marsh. B-roll would be the wide reverse shot showing what he sees from his porch. You might use a reverse over the shoulder shot to include him in the frame as a means of establishing the interviewee at the location and also to have plausible interview cutaways to cover edits to the interview itself. Shots of things like hand closeups while he talks or details of the porch, yard or house that help illustrate character or personality of the person.
Subject relevance: B-roll shots should illustrate something about the story. If your subject was pollution in the marshes, your b-roll would show examples of that, not pretty shots of waving marsh grass. Focus on the story and let that guide your shot selection.

 

[deltoidjohn]

+1 to all of the above

#1 advice I'd add is "move the tripod!"

I've had several shooters hand over b-roll where they turned up in a location, set their tripod up and shot everything from that spot. Nothing cut together because it all looked like jump cuts - different framing but everything was essentially the same viewpoint. In a wildlife/wilderness situation it's easy to be lazy because moving the tripod can mean a long hike carrying heavy gear, and it risks scaring off your subjects, but failure to do so makes for a very difficult edit.

Obviously all the standard stuff applies, like getting a variety of wide-mid-cu shots, static/panning/moving shots, continuity (with wildlife this will mostly relate to the sun position - eg you can't shoot the establishing shots at dusk and then cut to detail shots under midday sun), etc.