The optical construction of the Samyang 8mm T3.8 Fish-eye CSII DH VDSLR (Video DSLR) DH lens is based on the 8mm 1:3.5 Fish-eye CS model, and is specially developed for filming and video with APS-C sensor digital SLR cameras and professional camcorders with corresponding mounts. This CSII version features a removable lens hood (DH), but is otherwise identical (optically and mechanically) to the standard version with a fixed, non-removable lens hood. The Samyang 8mm T3.8 fisheye lens has an aperture of f3.5 (indicated as T3.8, which is the f-number of a lens corrected for light loss during transmission through the lens). T-values are important in the film industry, where TTL metering is not common, and also help to distinguish this video version of the lens from the standard Samyang 8mm F3.5 fish-eye. Optically, they are identical, with 10 elements in 7 optical groups, one aspherical lens element and multi-layer optics. The features of this new model include geared click-stop rings compatible with professional gear-driven follow focus systems available in the film industry, as well as a de-clicked aperture ring with smooth adjustment. These modifications allow extremely precise control of focus and aperture during video recording / filming. This enables the ultimate manual control of exposure when shooting scene by scene with different intensities of light sources, such as changing exposure values (EV) from indoors to outdoors, or even in-camera fades, etc. It can also be used perfectly for photography; however, users may find the standard version with a clicked aperture (Samyang 8mm F3.5 fish-eye) perhaps more appropriate to avoid accidentally changing the aperture between shots. The Samyang 8mm T3.8 fisheye lens is a manual focus lens and offers a very large depth of field. The 8mm T3.8 fisheye features a detachable / removable lens hood for shooting on full-frame cameras to produce the widest possible image circle. On full-frame cameras with the lens hood removed, it produces a vignetted, almost circular image. This effect is required for users wishing to obtain the widest possible image / field of view for panoramic software on full-frame cameras, and is one of the specific reasons why Samyang produced this version with a removable lens hood. The Samyang 8mm fisheye lens is ideal for creating 360° panoramas and virtual tours, including full 360-degree images with appropriate equipment and various third-party panoramic software provided by other suppliers. Available in 10 mounts: Canon, Canon-M, Nikon, Pentax K, Sony A, Sony E, Four-Thirds, MFT, Samsung NX and Fujifilm X. The Samyang 8mm fisheye lens offers one of the best optics in its class, with an excellent price-to-performance ratio. A specialised lens, affordable for all videographers or photographers, particularly suited to panoramic and video use. specifications