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Bronica 645 Range Finder 65mm F4 lens
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PostPosted: Mon May 06, 2019 7:25 pm    Post subject: Bronica 645 Range Finder 65mm F4 lens Reply with quote

I'm reposting this here, I originally had it posted under Large Format.

I recently bought a Bronica 645 Range Finder 65mm F4 lens (lens only - no body). I've looked all over the internet trying to find info on how this lens works exactly? I downloaded a copy of the Bronica 645 camera owners manual, but its pretty much on how to use the camera. It is a manual focus lens, it has an aperture ring, but I can't determine if the aperture ring is electronic or if the aperture blades are hidden inside the lens. From what info I could find the lens electronically winds the shutter using power from the camera body. I was hoping to hack this lens and use it on a full frame Sony A7RII (crazy I know), but I'm hoping to be able to adjust the aperture. Also does anyone how much power/voltage would be needed to maybe electronically open the shutter without a camera body? Which electrical contact does what? Any info is appreciated.

Please note: There are no adapters that are made for this lens that I am aware of. I'm NOT seeking info on a lens adapter, I'm hoping to get some info on how the lens works thanks!



PostPosted: Sat Aug 28, 2021 5:18 am    Post subject: Reply with quote

I think this lens is newer than the 645 series.
It was probably made for the ETRS-i camera.
It is similar in appearance to lenses of the SQ-a system with the 8 gold contacts.
IIRC, I could DOFPV easily with the power off on my SQ-a.
I can't remember if it was a lever/pin, or rotating collar that actuated the aperture. There was a hefty arm type lever inside the body for moving the aperture.

That RF may stand for retro-focus Embarassed - which is quite plausible on a lens that wide in focal length...

Could you post a side on view showing the aperture and focus points?

Okay- I found the camera and your lens through Google-fu.
With it being a range-finder designed lens, aperture control is likely going to be a low priority.
A mechanical/electro aperture control could be possible- but I don't see why on a range finder system.
Actually got a bit confused as this lens kept on coming up as f4.5 on google- it took a while.