The Contarex Lens to Sony NEX Camera Speed Booster from Metabones allows Contarex lenses to be mounted to Sony E-Mount APS-C format cameras, increasing the angle of view and the maximum aperture of the lens by 1 f-stop. This photo accessory also comes with a detachable tripod foot that is compatible with Arca Swiss, Markins, and Photo Clam ball heads.
The Speed Booster condenses light from the lens and projects it onto the APS-C sensor without vignetting; this allows the sensor to capture all of the lens' transmitted light and effectively produce full-frame coverage on non-full-frame sensors. A corresponding increase in the maximum aperture of 1 stop makes the lens more effective in low-light situations and able to create a shallow depth of field.
Metabones' Speed Boosters are made of machined brass, finished in satin black, the camera-body, and chromium-plated on both mounts to ensure smooth mounting and reliability.
These speed boosters are only fully compatible with mirrorless cameras housing APS-C or smaller image sensors. They will physically fit the Sony A7/A7R full frame mirrorless cameras but the camera must be set in Crop Mode to fully support the speed booster's functions.
Automatic diaphragm (AE metering) and other auto functions are deactivated while Speed Booster is attached.