The brass mount combines high precision with rugged construction. High-precision, rugged brass bayonet mount.Meticulous deployment of these types of exclusive low-dispersion glass and optimization of power distribution gives SIGMA lenses superlative image rendition undiminished by residual chromatic aberration. In particular, FLD glass offers ultra-low dispersion in combination with high transmittance and the anomalous dispersion characteristics of fluorite. To minimize this secondary spectrum, which can be a serious issue with conventional lenses, SIGMA lenses feature up to three types of exclusive low-dispersion glass offering superior performance: ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion) and FLD (“F” Low Dispersion). Yet residual chromatic aberration known as “secondary spectrum” may still remain. Most chromatic aberration can be removed by combining a high-refractivity convex lens element with a low-refractivity concave element. The result is chromatic aberration, the color fringing that is particularly noticeable in telephoto lenses. This fact causes different colors of light to focus at slightly different points.
The FREE (fixed rear element extension) focusing system is used to correct various types of aberrations from the close distances to the infinity end and to produce images with low distortion.A new round iris diaphragm is used to enable rendering of soft round out-of-focus (bokeh) effect for illumination, shimmering on water surfaces, and other point light sources.This enables the reduction of flare and ghosting for the shooting of clear, high-contrast images even under backlighting and other adverse conditions. This lens uses the new-generation multicoating "HD Coating" that reduces the reflection rate in the visible spectrum up to 50% or more than conventional multicoating.They also feature a completely round-shaped diaphragm to produce a natural, beautiful bokeh (out-of-focus) effect in the foreground and background. They are treated with the HD coating, which assures much higher light transmittance than conventional multi-layer coatings to deliver sharp, clear images free of flare and ghost images, even under such demanding conditions as backlight.
These lenses inherit the distinctive visual description and a premium appearance of the acclaimed PENTAX Limited Lens series, while adding the state-of-the-art HD coating and a round-shaped diaphragm, to deliver even higher digital imaging performance in combination with a K-mount camera body.ĭeveloped based on the Limited Lens series renowned for the meticulous finish in every detail from the outstanding image rendition to the high-quality, hand-machined aluminum body these new lenses assure even better optical performance than the original Limited Lens-series models.
The HD PENTAX-DA Limited interchangeable lenses are designed for use with K-mount lens-interchangeable digital cameras. Leveres med innebygget motlysblender, bakre og fremre objektivdeksel