Metabones EF Lens to Micro Four Thirds T Speed Booster XL 0.64x

$35

Increase maximum aperture by 11/3 stop
Increase MTF
Makes lens 0.64x wider
Patented 6-element/4-group optical design by Caldwell Photographic in the USA
Supports 4k video mode with DX lenses (except on GH5).