Yotsudake is one of the traditional Ryukyu dances. The dancers wear a flower shaped hat, and a bingata kimono. They hold a pair of instruments similar to castanets which are made from four (yotsu) pieces of bamboo (take). They clap the yotsudake in time to the music.
These images were all shot with the Pentax 645Z and the 90mm lens. The 90mm lens is an excellent portrait lens, allowing a shallow depth of field when needed and also has image stabilization to reduce motion blur due to camera shake.