Introduced in 1961, the Canon 7 came at a very interesting time and amidst a conflagration of changes within the photographic world.  Leica continued their dominance of 35mm rangefinders with their Leica M. Nikon had discontinued their popular line of rangefinder cameras in 1959 and had turned their attention to SLR design with the launch of the Nikon F.  Canon had actually started to do the same with their Canonflex series.  Despite this changing of the tides, Canon engineers had been steadily working away at a new rangefinder design to cap off Canon's line of M39-mount cameras and in 1961 they brought out the Canon 7, which would go on to be their best selling camera of the lineup and would even outsell all Nikon M39 rangefinders cameras combined.

Even though the Canon 7 uses the same M39 threadmount as previous Canon rangefinders, this was about the only thing it had in common.  The Canon 7 design was very much of a blank slate and Canon took the opportunity to really build a camera that was top of the line and competitive in its contemporary market.  Notably the Canon 7 utilized a combined rangefinder/viewfinder window, similar to the Leica M3.  This window had selectable framelines for 35, 50, 135 and 85/100 each individually displayed except for the 85/100 setting which paired framelines in the finder. An additionally innovative touch was the framelines were labeled in the finder itself so you knew which focal length the camera was set to while focusing and composing.  

The Canon 7 also incorporated a built-in, coupled light meter.  The original 7 design used a selenium cell meter, while the later 7s (and 7sZ) had a battery-powered CdS meter.  This meter had a cell on the front of the camera above the lens mount with a display on the camera top plate.  The user would set their shutter speed then read the appropriate aperture setting and transfer that to the lens. It was a fairly fast and easy system to use and greatly increased the versatility of the camera.

The other big feature of the Canon 7 was the inclusion of a secondary lens mount.  While the camera's main mount is the M39 threadmount, the Canon 7 featured an auxiliary bayonet mount around the threadmount.  This second mount was specifically for the famed 50mm f0.95 "Dream" lens that Canon also released in 1961.  This lens has gone on to become one of the most famous and sought-after lenses ever made.  While it has frequently been adapted to other lens mounts, especially Leica M and digital, the Canon 7 was the camera it was originally intended for. It is worth noting that the rangefinder base of the Canon 7 was increased by about 50% over previous Canon models.  This wider base helped give the camera's rangefinder increased accuracy which helped make focusing with telephoto lenses or the aforementioned Dream Lens much more accurate.

The Canon 7 was in production from 1961 until 1964, during which time it sold over 130,000 units.  An astounding number for such a late camera.  It was replaced by the Canon 7s which further refined the design of the original 7.  Notably, the 7s replaced the selenium cell light meter with a battery-powered CdS light meter.  The 7s also added an accessory shoe which the original 7 is infamously lacking.  An interlock was also added to the door release to help prevent accidentally opening the camera while film was loaded. The Canon 7s was produced from 1965-1967 but only about 16,000 units were sold. There is a late version of the 7s that is often referred to as the 7sZ (or 7s Type 2) that was made from 1967-1968.  The 7sZ is almost identical to the 7s, with a larger rewind knob (borrowed from the Canonflex cameras) and a new position for the RF adjustment screw.  Only 4000 7sZ are reported to have been sold.  Both the 7s and 7sZ are much less common compared to the original Canon 7.