Noun
focusing cloth (plural focusing cloths)
(photography, historical) A cloth thrown over a camera (and the operator's head and shoulders) to exclude all light except that which comes through the lens.
I remember being shocked when I came out from under the focusing cloth after a minute or two being submerged within that, at the startling green color of those ferns. John Sexton
And then as I frequently do, some times I'll peek out from underneath the focusing cloth and just look around the edges of the frame that I'm not seeing, see if there's something that should be adjusted in terms of changing the camera position. John Sexton