Mamiya C 105mm DS Lens: Slow Speeds and Shutter Release Delay
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
This lens arrived with typical slow speed issues and shutter release delay. What is interesting is that this lens is the 105mm DS version of the lens for the Mamiya C cameras.
There were six versions of the Mamiya C 105mm lens and the DS version started production in 1969 and this copy is from 1978. The DS version of the 105mm had two things that other C lenses did not: A “V” mode (self timer) and a diaphragm on the viewing lens to visualize depth of field.
Photo three shows the shutter with the front covers removed and located at around six o’clock in the shutter the self timer mechanism is visible. Also, the cocking ring is different than other Seiko shutters as it has teeth to make contact with the self timer.
If you are looking for a 105mm lens for your C series Mamiya, I’d suggest either the DS or the late model D, both have the same optics. The early D lenses were made to be a less expensive version and have a four element design. Later D and DS are improved five element design. Here is how to tell what version of the D lens you have:
Early versions were made from July 1969 to January 1971, later versions from February 1971 to April 1974. The date code on these is usually located on the side of the lens barrel. Also, if you feel like measuring, the thickness of the early D lens is 34.95mm while the later models are 36.25mm. This is the distance from the lens mounting plate to the front of the filter ring.
