The Metabones Speed Booster ULTRA Nikon F-mount to Sony E-mount improves on the original Speed Booster with a 5-element | 4-group optical design incorporating ultra-high refractive index tantalum-based glass for improved sharpness and reduced distortion and vignetting. The Speed Booster ULTRA allows you to mount a Nikon F full-frame lens on an E-mount body equipped with an APS-C sensor, increasing the angle of view and maximum aperture by approximately one stop. It is compatible with NIKKOR F and G lenses, including AI and non-AI mounts. When a lens designed for full-frame sensors or 35mm film is mounted on a body with an APS-C sensor, it transmits a larger area of light than the smaller sensor is designed to accept, increasing the effective angle of view of the lens. The Speed Booster condenses the light from the lens and projects it onto the APS-C sensor, allowing the sensor to use all the light from the lens and effectively reducing the crop factor of an APS-C E-mount body from 1.5x to 1.07x, producing a full-frame angle of view with an APS-C sensor. A corresponding increase in maximum aperture of one stop makes the lens more efficient in low-light situations and capable of creating shallow depth of field. Metabones Speed Boosters are manufactured from precision-machined brass with chrome plating on the body and lens sides of the booster to ensure smooth mounting, superior aesthetics and durability. This adapter features a removable tripod foot compatible with Arca Swiss, Markins and Photo Clam ball heads. Although the lens fits physically, automatic aperture (AE metering) or other automatic functions are not retained with this Speed Booster. An integrated de-clicked aperture ring allows manual control of the aperture from the Speed Booster. This 8-position ring with clear 1 | 2-stop graduations is supplied de-clicked but can be converted to a clicked version using the included ball and spring. These Speed Boosters are only fully compatible with mirrorless bodies equipped with APS-C image sensors or smaller. They physically fit Sony full-frame mirrorless bodies, but the body must be set to Crop mode to fully support the Speed Booster functions. - Allows mounting of a Nikon F full-frame lens on an APS-C E-mount body and, in doing so, increases the angle of view and maximum aperture by one stop. - The Speed Booster ULTRA design incorporates ultra-high refractive index tantalum-based optical glass for improved optical performance with better corner sharpness and reduced distortion and vignetting. This glass technology and optical design works extremely well with professional f | 2.8 zooms and fast prime lenses such as a 50mm f | 1.2 which will perform like a 35.5mm f | 0.9 with high contrast and high resolution from centre to edge of the image. - Precise fit and solid connection – the lens has no play, gap or wobble when mounted on the Speed Booster and no adjustment is needed to fit your lens. The body side and lens side of the Speed Booster are manufactured from precision-machined brass and chrome-plated. - The Speed Booster uses a matte black coating to minimise internal reflections to maintain the highest possible optical quality with the lens. The exterior features a black satin surface finish. - An integrated de-clicked aperture ring allows manual control of the aperture from the Speed Booster. This 8-position ring with clear 1 | 2-stop graduations is supplied de-clicked but can be converted to a clicked version using the included ball and spring. - The Speed Booster is compatible with NIKKOR F and G lenses, including AI and non-AI mounts. - Designed to achieve infinity focus whilst maintaining the correct registration distance required to maintain the optical quality of CRC lenses or floating element lenses. - The Speed Booster features a removable tripod foot compatible with Arca Swiss, Markins and Photo Clam ball heads. - Although the lens fits physically, automatic aperture (AE metering) or other automatic functions are not retained with this Speed Booster. Technical Specifications Lens Mount Nikon F Mount Magnification - 0.71x Crop Factor With APS-C format body: 1.07x Maximum Aperture F | 0.90 (with f | 1.2 lens mounted) Rectilinear Distortion < 1% Optical Construction Five elements | four groups Length Reduction Zero point seventeen inches (4.2 mm) Tripod Mounting Removable with Arca Swiss compatibility Weight 6.8 oz (193 g)