Here are some practical examples of photos shot throughout the Sony a6400's ISO range from ISO 100 through ISO 102400.
Sony a6400 Portraits: Small, light weight and easy to use
Sony A6400 Mirrorless camera body
Sony Alpha a6400 Mirrorless Camera ILCE6400/B - Adorama
Sony a6400 High ISO Sample Images Test & Review
Sony a6400 Test & Review
Sony Alpha A6400 First Impressions Sample Photos
Sony a6400 Review
Sony A6400 Review
Sony a6400 review: Digital Photography Review
Sony A6400 review
Sony a6400 Review
Sony - Alpha a6400 Mirrorless Camera (Body Only) - Black
Sony Alpha a6400 Mirrorless Camera with 18-135mm Lens — Glazer's Camera
Sony A6400 vs Sony A330 Detailed Comparison