Pentax 50mm 1.4 FA Classic

Through targeted fine-tuning of the lens construction, this lens has been designed to create a unique visual effect known as "Rainbow Flare" when shooting wide open (up to F4) and in strong backlight. By changing the composition or the position relative to the light source, the photographer can influence the position and size of the effect. When mounted on an APS-C format digital SLR camera, it can be challenging to produce rainbow reflections, as the camera's image sensor is designed to only utilize the central area of the lens's image circle. By stopping down to F4 or lower, the photographer can capture sharp, clear, and brilliant images—free from the "Rainbow Flare" effect—that are not only devoid of rainbow flare but also free from ordinary flare and ghosting. To utilize the "Rainbow Flare" effect even in bright lighting conditions while shooting wide open, it is recommended to use a commercially available ND filter (Neutral Density) that reduces light transmission. An ND16, which reduces light transmission to less than 1/16, is included with this lens.