Pentax LX. The Pentax LX was Pentax’s top of the line professional grade camera. Introduced in 1980 it remained in production for 21 years until 2001. While changes to the outside and operation of the camera were small during this time there were quite a lot of component changes inside the camera. This can sometimes make repairs difficult as all these components were not interchangeable. Compared to the rival professional cameras of the time like the New Canon F-1 and the Nikon F3 the Pentax LX held up well and was also smaller & lighter. The camera could be used without batteries at speeds of 1/75th and above but needed batteries for speeds of 1/60th and lower. The LX uses dynamic, off-the-film-plane TTL metering also called Integrated Direct Metering (IDM).