Canon FD-Mount and Canon FD-Mount Breech are two variations of lens mounts developed by Canon for their 35mm SLR cameras. While they share similarities, there are key differences between the two that photographers should be aware of. Let's delve into the specifics of each mount to understand their distinctions.

Canon FD-Mount

The Canon FD-Mount, introduced in 1971 with the Canon F-1 camera, quickly became a standard for Canon's SLR lineup. It featured a breech-lock mechanism, characterized by a rotating ring on the lens barrel that locked the lens securely onto the camera body. This mount was known for its robustness and reliability, providing photographers with a stable connection between the lens and the camera.

Features of Canon FD-Mount:
- Breech-lock mechanism for secure attachment
- Compatible with a wide range of Canon FD lenses
- Supported aperture priority and manual exposure modes
- Commonly found on Canon's classic SLR cameras from the 1970s and 1980s

Canon FD-Mount Breech

The Canon FD-Mount Breech, also known simply as the "Breech Mount," is a variant of the original FD-Mount. It was introduced later in the production cycle of Canon FD lenses to address certain usability concerns and improve compatibility with newer camera models. The primary difference lies in the design of the breech-lock mechanism.

Features of Canon FD-Mount Breech:
- Enhanced breech-lock mechanism for smoother operation
- Improved compatibility with certain camera bodies
- Revised lens release button for easier lens removal
- Retains compatibility with existing Canon FD lenses

Key Differences

While both mounts share the same underlying principles, the Canon FD-Mount Breech offers refinements in usability and compatibility. The enhanced breech-lock mechanism and redesigned lens release button make it easier for photographers to attach and remove lenses quickly, especially in fast-paced shooting scenarios.

Photographers using Canon FD-Mount cameras should ensure compatibility with their specific camera body and lens type. While many FD lenses are interchangeable between the two mounts, some cameras may require adapters or modifications for optimal performance.

How do I differentiate between a Canon FD-Mount Lens and a Canon FD-Mount Breech Lens?

There are several ways to distinguish between a Canon FD-Mount Lens and a Canon FD-Mount Breech Lens:

  • Physical Appearance: Canon FD-Mount Breech lenses typically have a larger, more pronounced breech lock ring near the base of the lens, whereas Canon FD-Mount lenses usually have a smoother, uniform design.
  • Mount Mechanism: Canon FD-Mount Breech lenses feature a rotating breech lock ring that allows for easy mounting and dismounting from the camera body, while Canon FD-Mount lenses often utilize a traditional bayonet-style mount without the breech lock mechanism.
  • Markings: Canon FD-Mount Breech lenses may have specific markings indicating the presence of the breech lock mechanism, such as "Breech-Lock" or "FL" (for "Flanged"). Canon FD-Mount lenses, on the other hand, may lack these markings.

By examining these characteristics, you can easily identify whether a lens is a Canon FD-Mount Lens or a Canon FD-Mount Breech Lens.