ASAHI Pentax Spotmatic
In the mid 1950s Pentax, or ASAHI as the company was properly called developed a series of cameras which led to the ones we know today. The history is well documented else where on the internet so...
With the success of the earlier 'S' series bodies ASAHI were tempted to be bold.
In 1964 pentax introduced the Spotmatic, one of the first cameras to use through the lens metering. This family grew from the original SP to the SP500, SP1000, SPII Spotmatic F and Electro Spotmatic which became the ES when full production commenced, finally production ended in the early 1970s
The Spotmatic gave way to the 'K' series, the first being the K1000.
The K-m and K-x models followed until Pentax (it's True name by now) produced the ME, the rest is history.
For more info on the early bodies see this site:-