The “D” means you can have the date imprinted on the picture. With the switch next to the viewfinder you can turn off this feature. The SD adds a self-timer and a date option to the top of the S model. The SD give you the versatility of adding a date from 1978 to 1992. A true testament to Minolta's commitment to innovation and user-friendly design, the Hi-Matic SD remains a charming and reliable choice for those who appreciate the timeless appeal of analog photography.