NPS 400mm f5.9 for M42 brand_Pentax just doubles your focal length

just doubles your focal length at the cost of a few meagre stops of light

5 is a good quality telephoto lens for Konica Autoreflex SLR cameras

and the High Speed AF mode offers improved autofocus speeds while maintaining 12

so keep it in mind

Lens boards for cameras such as the Sinar F

NPS 400mm f5.9 for M42 brand_Pentax just doubles your focal lengthThis is a simple (but large) telephoto lens for the M42 thread mount. In the old tradition of simple telephoto lenses, close focusing distance is 18 feet, and best performance will not be had at f5. 9. But, theres a tripod mounting collar, the glass is clean, and focusing is smooth. The mount is even interchangeable (its a T mount)