Mamiya Mamiya-Sekor Z 150mm f/3.5 W

Strobes at 1/400, full power, in a daylight studio with the modeling lights off and the sun coming through the north window. The leaf shutter sits inside the barrel, so it syncs flash at every marked speed up to 1/400, which means you can drag a bright ambient background down to black and still freeze a strobe pop on skin. A Hasselblad shooter with a focal-plane 150 is stuck at 1/90 sync and watching the highlights blow. On the RZ67 you just keep cranking the shutter. That single trick is why this lens has lived in commercial portrait studios for forty years.

On 6x7 the 150mm reads like a 75mm on full frame, the no-drama portrait length. Stopped to f/8 it is clinically sharp corner to corner across that big negative, which is the point: you want every eyelash on a headshot, and you get it. Wide open at f/3.5 it softens just slightly and the background goes to a smooth, undramatic wash. This is not a swirly-bokeh character lens. The out-of-focus rendering is calm and creamy, with edges that stay even rather than nervous. Color is neutral and contrast is moderate, the kind of well-mannered signature that lets you light the subject however you want.

It is one of the standard W-series Sekor Z optics for the RZ67, covering the full 6x7 frame, and the leaf shutter is electronically controlled by the camera body rather than cocked and timed inside the lens. It takes 77mm filters, a comfortable size for a polarizer or a grad when you take it outdoors. People do shoot it for landscape and product on a tripod, but its native habitat is the studio and the location portrait.

The honest weakness is the whole system around it. The RZ67 with this lens mounted is a heavy brick, and the lens has no fast aperture to brag about. If you want shallow medium-format separation wide open, the 110mm f/2.8 is the lens people reach for instead, and they often cross-shop the two before settling on the 110 as the everyday portrait glass and this 150 as the tighter headshot option. Focusing is by bellows on the body, not a helicoid on the lens, which is glorious for close work and slow for candids.

That bellows is the metering catch. The RZ67 racks its front standard out to focus, so at tight headshot distances you lose real light to extension and a straight incident reading will leave you underexposed. Set the focal length and your focused distance in Zone Light Meter and it computes the bellows factor for you, so the strobe power or shutter you dial in already accounts for the extension. A clean Z 150mm W trades cheap today, often bundled with a body, and there is little reason to pay more.