- 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).
- Can be powered either by camera body or by third-party external 5V power source (not included)
- Iris/aperture controlled by the camera body
- Smooth iris support with the latest Canon (2009+), Tamron (SP series 2013+) and Sigma (2016+) lenses
- Image stabilization (IS) lens support
- Support for cameras with in-body image stabilization (IBIS), including Panasonic GX7, GX8, GX80/85 and Olympus cameras
- Electronic manual focusing (e.g. EF 85/1.2L II and discontinued EF 50/1.0L)
- EXIF (focal length, aperture, zoom range)
- Distance and zoom display on camcorders (requires lenses supporting distance information)
- Detachable tripod foot compatible with Arca Swiss, Markins and Photo Clam ball heads.
- The opening is flocked with felt material to reduce internal reflection.
*** Supports only Panasonic GH4, GH3, G3, G5, G6, G7, G10, GF3, GF5, GF6, GX1, GX8, GX80/GX85, Olympus E-PL7, PEN-F, Blackmagic Cinema Camera with Micro Four Thirds mount**, Pocket Cinema Camera*** and Micro Cinema Camera***