The five blade Synchro Compur #1 is probably the most numerous of all the Compur shutters. It features shutter speeds from 1/400 Second to One second as well as "B" and "T" Speeds are selected by turning the knurled outside speed dial. There is an additional spring engaged when setting the shutter to 1/400 second. This takes a fair amount of force to turn to 1/400 second and may be very difficult to set to the highest speed with the shutter cocked. This is normal operation. The shutter is released by operating the release lever or using a cable release in the release socket. The Green "M/X" lever sets the flash contacts to be used with electronic flash or flashbulbs. Normal flash setting for modern electronic flash is "X"

The Synchro Compur # 1 has both the self timer and press focus.

The #1 shutter has both self timer and press focus. The square stamped lever/button can be used to open the blades when the shutter is cocked. The round button to the right operates the self timer. (Set the cocking lever then push the button, this allows the cocking lever to move a little more and engage the self timer. above. The two controls operate independently of one another. The blades should open when the press focus lever is pushed in and close crisply when the lever is pulled back out. It is a common fault/defect that the blades stick open and do not snap shut when the lever is pulled back out. Even in the case of defect, the blades will usually close if the shutter release is operated.

The #1 shutters take lenses mostly of 200mm and longer and were used exclusively on cameras with view backs or at least cameras which could accept an accessory view back.