This is a groundbreaking telephoto lens that smashes conventional telephoto lens concepts through a combination of optical glass element and crystal fluorite (CaF2) lens element that has special optical properties. It has the features such as being compact, high resolution, being apochromatic and high contrast.
Crystal fluorite features a low refractive index and low dispersion that are not easily obtained using optical glass, while also being extremely effective in the elimination of secondary spectrum chromatic aberration (residual aberration) that is difficult to compensate for. These characteristics combined with optical glass made it possible to complete this apochromatic lens. Reduced resolution in telephoto lenses is mainly caused by chromatic aberration, and images tended to be flat. Despite being a telephoto lens, this lens succeeds in creating a high-contrast frame with the high resolution of 100 lines per millimeter even at the edge of the frame. At the same time, the zoom ratio is extremely small at only 0.65 (1.0-0.95 in conventional optical systems), making the lens suitably compact for handheld shooting.