Before chasing sharpness, consider long-term reliability. I've seen some Viltrox AF issues impact camera mounts over time. Maybe check used Fujin...

Sharpness-wise, Viltrox 56mm f/1.4 is decent. But honestly, I had focusing issues after a year. Consider the used Fuji 50mm f/2. Tack sharp, reliable,...

Wildlife, eh? Skip chasing Fuji sharpness alone. Honestly, I've had issues with their telephoto reliability. For birds and $2000, research Tamron...

Watch bitrate! GoPro Hero Session (used) offers great image quality, but check specs carefully.