It is unfortunate to be limited by your equipment like that. To be able to only stop down not open up. This is why this is the 35mm camera thread, 35mm cameras are more flexible with regards to exposure. Why do u keep mentioning your 120 camera? And yes, the correct answer to the OP's question for a mechanical camera would be a Nikon FM2/n, FM3a or perhaps Pentax LX. The latter two have hybrid shutters.