How do electrochromic lenses compare to photochromic lenses for skiing?

Electrochromic lenses adjust tint electronically at the push of a button, typically shifting VLT from ~10% to ~70% in seconds. Photochromic lenses adapt automatically based on UV exposure but can take 30-90 seconds to transition and may not darken fully in very cold temperatures. Electrochromic gives you manual control and faster response, but requires battery power. Photochromic is automatic and battery-free but slower and temperature-dependent. Both eliminate the need to swap lenses, but electrochromic offers more precise control.