I was first interested in this camera because of the chunky lens, it seemed typical Mamiya.Introduced in 1966, the 500 TL and 1000 TL took M42 lenses. However, because the outer ring on the 55 mm lens protrudes behind the seating flange, it will jam on some other M42 cameras though their lenses will fit the Mamiyas.The 55 mm lens is 6 element with automatic stop down. Focussing is by means of a microprism and metering by a needle, with 1.5 V battery.A unique feature of these Mamiyas is that in 1967 they were the only spot metering M42 SLRs.Metering is from a 10% area of the subject, a rectangle at the bottom center of the frame.(There was a slightly different DTL version).The meter is activated by pushing the film advance lever towards the camera body. Some 1967 prices, GBP: Pentax Spotmatic +1.8 -120, Mamiya 100- TL+1.8 -85,Prakticamat +Oreston -90. Taking a Mamiya 67 on holiday gives a story to dine out on for ages, my 500TL is still quite heavy so here are a couple of pics from it using a red filter on a hazy day.