Changing lenses and trail treeroots are the two main reason I wear knee pads while hiking with a camera.  I surprisingly saw this little toe-hooker and originally setup to shoot a scene of the creek through it, but there was no such scene to be seen.   I shot it anyway. 
ILCE-7R with 24-105mm F4 OSS @50 mm, 2.5 sec at f / 16, ISO 125