 The dot that was green on negatives was red on slide film and so stereo hobbyists could tell which chip was the left frame after
cutting the film by looking for the red dot.Because many slide mounts were designed for an image frame taller than the Nimslo frame this red dot was sometimes visible in the picture.The glass lenses and automatic exposure control of the Nimslo made it well suited for this purpose, unlike similar cameras such as the Nishika that typically sported plastic lenses and limited adjustability, relying on the latitude of the print film to give good results under varied lighting conditions.