Fibre-optic strobes are the standard. Optimal position: 20-25 cm on each side of the dome port. Macro at 25-50% power. Anodised aluminium vs polycarbonate housings. Sea&Sea YS-D1 and YS-D2 compared.
Sea&Sea strobes (especially the YS-D1 and YS-D2) feature in numerous discussions about malfunctions, repairs, and controversy about their quality. Questions also arise about how to carry the camera on a buoy, removing dome port glass, repairing scratches on domes, and fiber-optic connectors. It is a niche with a strong DIY component where hardware failures generate considerable frustration.
External strobes connected via fiber-optic cable have become the standard for their simplicity: they use the built-in flash burst as a slave trigger. The optimal position is to place the strobes 20–25 cm to each side of the dome and slightly behind the plane of the port, minimizing backscatter. For macro, reduce power to 25–50% and bring the strobes closer; for wide angle, move them further apart and angle them outward. Anodized aluminum housings offer greater resistance than polycarbonate, although their cost can be three times higher.