The T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera fromMetabones allows a Canon EF or EF-S mount lens to be mounted onto a Sony E-mount camera. While doing so, the adapter is designed to support electronic communication between an attached camera and lens. If the lens includes autofocus, image stabilization, as well as camera-controlled aperture functions, this adapter is intended to allow those features to be used. If an attached lens is also capable of generating EXIF metadata when used with a directly compatible camera, the T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera is designed to allow that information to be saved along with image files generated with a combination of the lens, a Sony E-mount camera, and the adapter.

By enabling camera-controlled aperture functions for a Canon EF or Canon EF-S Mount Lens when used with a Sony E-mount camera, program, shutter-priority, aperture-priority, as well as manual modes can be set and used through the camera. Power for these functions is transferred from the camera to the lens, and the T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera is designed to accomplish this in an energy-efficient manner. When manual focusing is preferred with a compatible electronic lens, an integrated switch can be depressed which opens the lens's aperture diaphragm to it largest setting. The resulting shallow depth-of-field can then be used to help ensure focus accuracy.

When an image is taken with the T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera, a matte black internal coating minimizes the potential for reflections within the adapter barrel, which could otherwise result in unwanted glare within the image. The adapter barrel also features a wide internal diameter to support the movements of compatible tilt-shift lenses.

The T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera is constructed from aluminum alloy for durability while minimizing weight. Its mounting rings are made with brass to further prevent wear-and-tear, and a detachable tripod foot is included that features 3/8" threads as well as compatibility with Arca-Swiss tripod heads.

While Canon EF-S or third-party APS-C EF-mount lenses may be used with the T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera, vignetting may occur when such lenses are combined with this adapter and a Sony E-mount camera with an APS-C sized sensor. Canon EF-S and third-party APS-C EF lenses are designed to project an image onto sensors measuring 22.3 x 14.9mm, while Sony E-Mount APS-C cameras feature sensors that measure 23.5 x 15.6mm.

The T Smart Adapter Mark IV for Canon EF or Canon EF-S Mount Lens to Sony E-Mount Camera can be used to connect Canon EF or third-party "full-frame" EF-mount lenses to a Sony E-mount camera with a "full-frame" sensor without vignetting. It may be used to adapt Canon EF-S or third-party APS-C EF-mount lenses to a "full-frame" Sony E-mount camera as well. However, Sony E-mount cameras with a "full-frame" sensor must be set to "crop mode" when combined with this adapter and Canon EF-S or third-party APS-C EF-mount lenses to avoid generating images with vignetting.