The Bronica ETRS is an improved version of the ETR. The main improvement is the interchangeable viewfinder system. The newer AE II and III finders are not fully compatible with the older ETR cameras, because there is a new electronic connector pin. The shutter button lock has been redesigned. It has three settings, unlocked, shutter release button lock but drive and cable release unlocked, and all locked. The neck strap mount has been changed to a design with an eyelet while the previous one was a spring catch style mount used on the Bronica 6x6's