Bronica / Nikkor Zenzanon-PS 50mm f/3.5

Fill flash at 1/500 against a blown-out midday sky, aperture wide enough to drag the background down, no high-speed-sync trickery required. That is the trick this lens pulls that a 35mm SLR cannot. The shutter lives inside the lens barrel, not the body, so it syncs flash across the full speed range instead of capping you at the 1/250 or slower that a focal-plane curtain allows. A photographer chasing flash plus shallow depth in full sun spends the day fighting a 35mm body. On a Bronica SQ with this 50mm, you balance the strobe and the ambient and shoot. That capability kept these cameras working in commercial and catalog studios well into the digital era.

The 50mm covers the 6x6 frame and gives you roughly the angle of view of a 28mm on full frame, so this is a genuine wide. A wide that short on an SLR has to be a retrofocus design to clear the mirror box, and the PS series is Bronica's second-generation SQ optic, built for its own Zenzanon line with improved multi-coating. (By the time the SQ system arrived, Bronica had been making its own Zenzanon optics for years and Nikon had long since stopped supplying Nikkor lenses, so these are not Nikon-made lenses despite what some listings imply.) Stopped to f/8 or f/11, where most medium-format work actually happens, it gives you a flat field and low distortion. Straight architectural lines hold straight, and the corners stay clean across a square negative, which is not a given at this focal length.

Wide open at f/3.5 it softens and loses some contrast, normal behaviour for a retrofocus wide, but nobody buys a 50mm of this type to shoot it at f/3.5. Flare is where it can let you down. The big front element and the 77mm filter ring sit well forward of the body, and a strong backlight will lift veiling glare across the frame if you have left the dedicated hood off, so keep it on. Color is neutral and leans slightly cool, no warm signature baked in, which is what you want from a system built to reproduce product and skin honestly rather than flatter them.

The people running these were studio and commercial shooters on the SQ-Ai and SQ-B, plus environmental-portrait and documentary photographers who wanted a single wide that could take in a room and the person standing in it. It never became a landscape cult object the way a few medium-format wides did, and part of that is cost. Bronica SQ gear has long sold for noticeably less than equivalent Hasselblad kit on the used market, which is most of why people buy into the system: leaf-shutter flash sync and sharp medium-format optics without the Hasselblad premium.

The honest weakness is the shutter. Leaf shutters in old SQ lenses gum up over the decades, and a 50mm that hangs or runs slow at the 1/4 and 1/8 marks is common enough that you should assume a CLA before trusting it for paid work. For metering, the leaf shutter is the thing to plan around. Because it syncs flash up to 1/500, set the strobe exposure off your aperture, then let Zone Light Meter read the ambient for the background separately and balance the two. The 77mm thread is also where your ND and square grads go when you want to slow that fast-sync shutter down outdoors.