Rokinon is the leader of the cost-effective manual-focus lens movement. Offering more focal lengths for more mounts than any other company, Rokinon has also broken ground providing faster optics at more affordable prices than any other lens manufacturer in the world.
Question: Why use manual-focus lenses?
Answer: For most motion picture applications, manual focus lenses are preferred. Autofocus lenses are optimized for autofocus. This means the focus barrel travels a shorter distance when focusing. This is great for autofocus, but it offers less precision when focusing manually. Additionally, the lens barrels on autofocus are meant to move very quickly, to enable fast autofocusing. However, when focusing manually, this results in a focus movement that can appear more jittery and less smooth than a dedicated manual focus lens. On the contrary, the barrels of manual focus lenses are "dampened," which means the movement when changing focus is very smooth. This is evident when watching your footage - changes in focus are more aesthetically pleasing.