- Based on the ZEISS Sonnar optical concept, this lens uses a design with seven elements in five groups that helps achieve the large maximum aperture of f/1.8 while simultaneously reducing flare and improving contrast.
- Bright f/1.8 maximum aperture allows users to create images with shallow depth of field and work in low-light conditions with relative ease.
- Three aspherical elements, including two double-sided, are incorporated in the lens design to reduce astigmatism, field curvature, coma, and other monochromatic aberrations.
- ZEISS T* anti-reflective coatings have been applied to each lens surface to help minimize reflections in order to provide greater image clarity, contrast, and color fidelity.
- Rounded nine-blade diaphragm contributes to a pleasing bokeh quality when employing selective focus techniques.
- Linear autofocus motor and internal focus design provide quick and precise autofocus performance and enables accurate and silent focusing while recording videos.
- Dust- and moisture-sealed design better permits working in inclement conditions and rubberized control rings benefit handling in colder temperatures.
The Hoya 49mm alpha Circular Polarizer Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. The light from the sun naturally becomes partially polarized due to reflecting off electrons in air molecules, causing the light to scatter into what appears as haze. A polarizing filter arranges, and filters, this directionally polarized light perpendicularly to the reflected light, allowing for the absorption of much of this light. This results in a noticeable reduction of glare and reflections from non-metallic surfaces and an increase in the saturation of skies and foliage.
A circular polarizer only differs from a linear polarizer in that it contains a quarter wave plane in addition to the linear polarizing filter. The addition of this quarter wave plane is to circularly polarize the linearly polarized light for the use of auto focus and exposure functions. Due to how the light is broken down and filtered with a linear polarizer, auto focus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.
This filter is non-coated and has approximately 96% average light transmission. It is constructed from optical glass and precision milled aluminum frames.