The story
Blend of sports + viewfinder.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A kind of camera viewfinder made from wire rectangles, including a smaller one nearer the eye and a larger one further away, with no optics. The smaller rectangle was centered in the larger, which would then give an indication of what would be included in the photograph. Full definition →
Blend of sports + viewfinder.
Etymology from Wiktionary, CC BY-SA 4.0.