I believe the OP said smaller and lighter than a modern Mamiya 6 - so I'm not sure why everyone's suggesting TLRs, which are neither small nor particularly light.
I encountered this problem - wanting a small 6x6 camera - last year, and as mentioned in some replies, the answer was a folding camera. They're typically about the same size as a Leica M when folded except about an inch taller.
My criterion was usability, so I needed a folder with all that a modern photographer considers essential. A modern folder like a Mamiya or Plaubel was out of my price range, so it had to be an older one.
I'd make a list of what you require from your folding camera. My requirements were:
• Small
• Comfortable
• Reliable
• Wide range of shutter speeds
• Wide range of apertures
• High-quality lens
• Bright, accurate viewfinder framing (i.e. a rangefinder
or at least brightlines with parallax correction marks)
• Fast to shoot (i.e. has a film advance mechanism -
not the usual slow rewind knob and red window)
• Built-in light meter
Playing with the folders in my local camera shop, it was disheartening to find how bad folders are and how few met the above rather basic requirements - most are poorly designed, uncomfortable to use and about as modern as a flint axe! For example, why are their viewfinders so small and squinty compared with excellent - and cheaper - 35mm cameras from the same era, and why do so few (even the expensive ones aimed at pros) have film advance mechanisms like their 35mm brethren? I guess portable medium format cameras just weren't sexy after the War, so manufacturers put their innovations into the 35mm format. Anyway, I digress...
I crossed "built-in lightmeter" off my list as such folders are astronomically priced (collectors...! :bang
🙂
My short list was:
• Iskra
• Certo 6
• Agfa Super Isolette
• Zeiss Super Ikonta
These all met my requirements, and have excellent f2.8 lenses (the last three have Zeiss ones), fast 1/500 s shutters and can fire electronic flashguns.
This website
http://www.certo6.com has a lot of info on folders.
I first bought an Iskra. Big mistake... imagine a camera made by a blacksmith. Good specifications on paper - but the build quality was crude, crude, crude - and it was painful to use (knurling on the focus ring was so sharp it took the skin off my fingers!).
😱
I then bought a Certo 6. It took a bit of hunting to find a decent one, but I'm really pleased with it. I had to chop it about to make it truly usable (sorry collectors!). For more details on my modified Certo 6, see
http://www.rangefinderforum.com/forums/showthread.php?t=65609
Lastly, these folding cameras are about 50 years old, so if you want reliability and peace of mind, it's worth getting it professionally serviced - when taking photos, you don't want to worry about the shutter jamming or incorrect shutter speeds, or find that you've developed a light leak.