Several purpose-built options were suggested for creating photography lighting diagrams:

• Sylights: a dedicated lighting-diagram tool; free registration required.
• OLDC / LightingDiagrams.com: a free online creator, with donation requested for commercial use.
• Photo Diagrams: a free Flash-based tool.
• Strobox: a free iPhone app.
• Lighting Studio Photo: free software that can create, print, save, and export diagrams as JPG, with settings for scene elements.

In practice, the main differences are usually platform and workflow:

• Web-based tools are easy to share and use anywhere.
• Desktop software may offer saving/export options and offline use.
• Mobile apps are convenient on set.

If your priority is sharing with crew, a web-based diagram tool is often the simplest choice. If you need printable diagrams or image export, a desktop app with save/export features may be better. Compared with Visio, these tools are more photography-specific and should make common lighting layouts faster to build.