Contax 50mm F/1.7 Planar T* C/Y Mount Lens {55}

Contax 50mm f/1.7 Planar T*: Zeiss glass on a budget

The Contax 50mm f/1.7 Planar T* is a Zeiss-designed normal prime in the Contax/Yashica mount, carrying the same T* anti-reflection coating and Planar optical formula that made Zeiss glass a benchmark for sharpness and color fidelity. At f/1.7, it sits in practical territory, bright enough for low-light work, and the Planar double-Gaussian design delivers smooth gradients in out-of-focus areas that synthetic corrections rarely replicate.

The C/Y mount adapts readily to Sony E, Fuji X, Micro Four Thirds, and most modern mirrorless systems, which is a large part of why this lens has stayed in circulation long after Contax ceased production. With a 55mm filter thread, it accepts common filter sizes without step rings. Manual focus is the only mode of operation, which on mirrorless bodies with focus peaking or magnification assist is a non-issue. For the price of entry into Zeiss optics, few 50mm primes in any mount come close.

Who It's For

Mirrorless shooters adapting vintage glass will find the C/Y mount compatibility broad enough to cover Sony, Fujifilm, and Micro Four Thirds systems with a single inexpensive adapter. Portrait photographers drawn to the Planar formula's rendering get f/1.7 light-gathering at a fraction of modern Zeiss pricing. Street and documentary photographers who prefer a fixed 50mm focal length and full manual control benefit from the deliberate, tactile shooting discipline this lens demands. Film photographers still running Contax or Yashica bodies get a native-mount lens with T* coating that was purpose-built for the system.

Key Features

• Zeiss Planar optical formula with T* anti-reflection coating
• f/1.7 maximum aperture for low-light performance
• 55mm filter thread for standard accessories
• Contax/Yashica mount with broad mirrorless adapter compatibility
• Manual focus operation
• Smooth bokeh rendering from double-Gaussian design

FAQ

What mount is this lens, and will it work on my camera?

It's Contax/Yashica (C/Y) mount. You'll need a C/Y to E-mount, X-mount, Micro Four Thirds, or other mirrorless adapter - they're inexpensive and widely available, and the manual focus experience on modern mirrorless bodies with focus peaking is seamless.

Is this lens autofocus?

No, it's manual focus only. On mirrorless cameras with focus peaking or magnified live view, that's not a limitation - it's actually an advantage for precise focus placement.

What filter size does this lens use?

55mm. That's a common size, so you won't need step rings or specialty filters.

How does the f/1.7 aperture compare to other 50mm primes?

It's practical for low-light work without being extreme. The Planar design handles that aperture with smooth bokeh and good corner-to-corner rendering, which matters more than the raw f-number.

What's the T* coating, and why does it matter?

Zeiss's T* anti-reflection coating reduces flare and internal reflections, which means cleaner contrast, truer color rendering, and less haze in backlit scenes. It's a hallmark of Zeiss optics.

Is this the same as the Zeiss Planar 50mm f/1.7?

It is Zeiss-designed and carries the Planar formula, but it's branded Contax and in C/Y mount. Optically equivalent to the Zeiss version of that era, just a different mount and brand house.