" 1. "HD coating " for exceptional images Featuring the original high performance multi coating "HD coating". When compared to conventional multi-coating, it has less reflection and higher transmittance, so it suppresses the occurrence of ghosts and flare under adverse lighting conditions such as backlighting, and achieves crystal clear images. This elevates the imaging performance of Limited lenses to the next level. 2. Round-shaped diaphragm for beautiful bokeh A newly added round diaphragm features on all lenses. It produces a natural, beautiful bokeh effect in the images captured, while optimizing the image performance of the distinctive Limited lens series optics. 3. Limited series Lens thats particular about image depiction and texture Whilst inheriting the design concept of the Limited Lens series, these lenses were subject to a series of mechanical and numerical performance evaluations, as well a visual assessment of the samples. The barrel, hood and cap are all made of high-grade aluminium, meticulously machined for an attractive appearance and beautiful texture. The HD PENTAX-FA 43mm F1.9 Limited features a mount pointer made of a Shippoyaki (cloisonné) ware. This pointer provides a firmer grip as featured on other Limited Lens-series models. 4. Other 1. SP (Super Protect) coating is applied to the front surface of each lens to repel dust and stains. 2. Black models are marked with a serial number starting with 0000001; silver models start with 1000001. 3. The aperture ring has been retained so that the user can still use a variety of functions featured in K-mount film-format cameras."