Asahi Pentax 6x7 MLU
Asahi Pentax 6×7 (MLU) – with a mirror lock-up mechanism, launched in 1976 (second generation)
Early in 1976, halfway through its production life, Asahi introduced a mirror lock-up feature. Sliding a switch on the right-hand side of the mirror housing upwards releases the mirror, while a small, flush button located under the numeral 7 in the model name on the right-hand front allows the mirror/shutter cycle to be completed if the shutter has been released without battery power; after depressing the button (e.g. with a ballpoint pen), press the shutter once more to complete the cycle. This feature does consume power, so remember to release the mirror.
