Konica introduced the Konica FS in 1961 or 1962 and it is a more affordable, less feature-laden model than the original Konica F model. The Konica FS can be found in both matte chrome and black versions and does not have a built-in light meter. It has 1/1000 top shutter speed (instead of 1/2000 as found on the F), but it continues to offer a 1/125 top sync speed with electronic flash. It saw much larger production run than the original F and was widely sold. Since it is nowhere near as uncommon or groundbreaking a model as its predecessor, the FS can be expected to sell for far less money. Chrome models generally sell at auction for $125 or less with a normal lens. Black models are rarer and might go as high as double that amount.
Some have stated that the shutter in this camera is the original Copal Square, which was developed by a consortium of manufacturers including Konishiroku, Copal and Mamiya. However, the shutter in the FS is not a Copal Square. However, the Konica FS instruction manual (seen here at Urs Brunner's Konica Collector website refers to it as a Konishiroku "HighSynchro" shutter. Now, this might have been built for Konishiroku by Copal... This sort of outsourcing was becoming common. So, it's possible the shutter is identical to the Copal Square in all but name. The downgrade from the shutter used in the F was probably done for practical reasons and improved reliability. Both the F and FS Konishiroku shutters (which had been in development since 1953) are quite clearly precursors of the Copal Square, which first appeared in a Nikkorex, then in the Konica FP, then went on to great success in a wide number of cameras and is the historical basis for shutters used in virtually all modern film and digital SLR cameras offered today.
The FS was sold with a 50mm f2 Hexanon normal lens that is somewhat unique to this camera model. That lens was not generally offered with the two later models.
Along with the FS was introduced an expanded line of system lenses covering 35mm to 800mm focal lengths. Actually the FS instruction manual continues to list three of the premium lenses that were offered earlier with the F(35/2, 85/1.8 and 135/2.8) as still available optionally for use with the FS. (Note: The four lenses that were introduced with the F in 1960 use a somewhat different mechanism to link the camera's match needle metering system, but do share the same bayonet and control the auto aperture function in the same way..... See Konica F discussion and notations.) All these lenses use the Konica Bayonet Mount "I" (the "I" is added here by me to distinguish from the later mount, but at the time it was simply known as "Konica Bayonet Mount"), 40.5mm flange diameter, and sometimes now referred to as the "Konica Early Bayonet Mount" or "Konica F-Mount".
However, a lens catalog provided with the FS (dated 1961) only lists one of the original four "F" lenses: the 135/2.8. The 35/2 and 85/1.8 are no longer listed. Perhaps by this time existing stock of those lenses had been sold off.
What were offered in the lens catalog were Hexanon 35/2.8, 100/2.8, the 135/2.8 already mentioned, 135/3.5 (with auto aperture), 200/3.5 (preset), 400/4.5 and 800/8. This line-up remained substantially the same through Konica FP and FM production (Note: New normal lenses were introduced with the later models: 52/1.8 and 52/1.4, plus both auto and preset versions of 35/2.8, 100/2.8 and 135/3.5 were eventually offered).
The camera (like all the early Konica models) has a small lever that peeks out from under the lens' base close to the 6 o'clock position during aperture operation. This connects to a matching lever on the lens and serves to close the lens aperture down very briefly during exposure, and yet allows it to remain fully open the rest of the time for a nice, bright viewfinder and easy, accurate focusing. At the time this was referred to as a "fully automatic aperture", which, in the late 1950s and early 1960s, was not yet a widely known feature of SLR cameras. Many systems from other manufacturers of the time and earlier still required the lens aperture be closed manually by the photographer, which was slower and resulted in a dimmed viewfinder especially when smaller f-stops were selected. By the mid to late 1950s a few SLRs had been developed to the point that the aperture closed automatically, but didn't reopen and needed to be manually reset. Nikon, Canon and Konica were among a fairly short list of new SLRs starting to feature this more convenient and quicker operating "auto aperture", which should not be confused with "auto exposure" methods that came some years later.
A few models of Hexanons didn't actually take advantage of the auto aperture feature and continued to use a preset manual or strictly manual aperture control, probably catering to customers who were "suspicious" of all the fancy new technology, preferring instead the older methods of operation. Some lenses were actually offered both in preset/manual and auto aperture versions.
There was a special variant of the FS made, the Konica FS-W.