Nikon SP is Nikon's best and most advanced rangefinder system. Quiet, smooth and competent at everything rangefinders are designed for. The SP was the first 35mm Rangefinder with six built-in framelines and Titanium shutter curtains. The combined Rangefinder/viewfinder window had projected parallax frames for the 50/85/105/135. To the left of the main window was the wide angle window, showing non parallax corrected views of the 28 and 35. The Nikon SP system is an amazing camera design and 35mm Photography achievement.