Soft box mount, including a receiver block for receiving an expander strut of a soft box. The receiver block includes, in this order, an inward part, a transverse pivot axis, and an outward part, the outward part of the receiver block being configured to receive a proximal end of the expander strut; and a bar block which is configured to be movable between a first, non-use position, in which the inward part of the receiver block may intrude into a recessed part of the bar block, and a second, use position, in which a non-recessed part of the bar block urges, from a light source side, the inward part of the receiver block to assume a position radially inward of the pivot axis of the receiver block, thereby urging the outward part of the receiver block to assume a position radially outward of the pivot axis of the receiver block.