The Brightin Star MF 7.5mm f/2.8 IV is a manual prime lens for mirrorless camera systems with APS-C and Micro Four Thirds image sensors. The model belongs to the group of fisheye lenses and represents the 4th version of this product line.
The optics cover a diagonal angle of view of 190 degrees. This wide field of view results in a pronounced barrel distortion in the images, which is typical for the design of fisheye lenses.
The outer housing of the lens is made of metal. It is available in two color variants: black and silver. The external dimensions are 6.4 cm in length and 5.3 cm in diameter. The total weight of the optics ranges from 274 to 291 grams, depending on the lens mount.
The lens has no electronic interfaces for signal transmission to the camera body. Both focusing on the subject and selecting the aperture are done purely mechanically via two separate adjustment rings. Brightin Star manufactures this lens for the Sony E, Fujifilm X, Nikon Z, Canon RF, Canon EF-M, and Micro Four Thirds camera systems.
The internal optical construction consists of 11 lenses arranged in 8 functional groups. To reduce optical aberrations, 3 lenses with high refractive index and 2 lenses with low dispersion are integrated into the system.
The maximum aperture is f/2.8. The aperture can be closed stepwise via the corresponding ring on the lens down to f/16. The aperture mechanism uses 5 individual blades. The minimum distance to the subject is 15 cm (close-up limit).
Since the front lens is curved outward, the lens does not have a classic front filter thread. For the use of optical filters, a rear filter thread with a diameter of 27 mm is available instead.
The operation of the lens follows the principles of classic manual camera systems. The user sets the focus manually on the lens. Exposure metering is performed by the camera body in aperture-priority mode.
