What is the Flash Speed of Pentax 67?

The Pentax 67 series, including the Pentax 67II model, features varying flash synchronization speeds depending on the type of shutter being utilized. For the camera's focal plane shutter, the flash sync speed is typically under 1/30 second, often effectively 1/30 second or slower. However, when using specific leaf-shutter lenses designed for the system, the flash can synchronize at much faster speeds, up to a maximum of 1/500 second.

Understanding Flash Synchronization in Pentax 67 Cameras

Flash sync speed refers to the fastest shutter speed at which a camera's shutter is fully open when the flash fires, ensuring the entire frame is exposed by the flash. In cameras like the Pentax 67, which primarily use a focal plane shutter, this speed is often limited.

Focal Plane Shutter Sync Speed

The Pentax 67 (and 67II) cameras incorporate a robust focal plane shutter. Due to the way this shutter operates – as two curtains moving across the film plane – there's a specific speed where the entire film frame is exposed simultaneously for a brief moment before the second curtain starts closing. For these cameras, this critical sync speed is under 1/30 second. This means that at shutter speeds faster than 1/30s (e.g., 1/60s, 1/125s, etc.), only a portion of the frame would be illuminated by the flash, resulting in an underexposed band across the image. For flash photography with the focal plane shutter, photographers must select a shutter speed of 1/30 second or slower to ensure proper flash coverage.

Leaf-Shutter Lens Sync Speed

A significant advantage of the Pentax 67 system is its compatibility with specialized lenses equipped with an integrated leaf shutter. These lenses effectively bypass the camera's focal plane shutter for flash synchronization. When a leaf-shutter lens is attached and its shutter is engaged, the flash can synchronize at much higher speeds, up to 1/500 second. This capability offers significant creative and practical benefits for photographers:

• Balancing Ambient Light: Faster sync speeds allow photographers to better control and underexpose ambient light while still using flash for their subject, creating dramatic effects, especially outdoors in bright conditions.
• Freezing Motion: A 1/500 second sync speed can more effectively freeze fast-moving subjects when combined with flash, reducing ghosting or motion blur from ambient light.
• Wider Apertures in Bright Conditions: Faster sync speeds allow for the use of wider apertures in bright environments without overexposing the image, enabling shallower depth of field.

Summary of Pentax 67 Flash Sync Speeds

This dual-shutter system provides photographers with flexibility, allowing them to choose the appropriate lens and technique based on their desired photographic outcome.