Unlike comparable medium-format cameras, the 645 does not have an interchangeable back system.

The new model also featured matrix metering, film-edge data imprinting, and a self-timer.

The imprinted data on the edge of every image includes the frame number, exposure mode, shutter speed, aperture, exposure compensation value, metering mode, and lens focal length.

The controls and LCD on the top plate were significantly changed, and the motor drive was increased to 2 frames per second.

The 645NII provides 10 Pentax Functions [PF] to set the camera according to the user's preferences.

It is approximately the same size and shape as the earlier film models, and the lens mount accepts older manual and auto-focus lenses.

On the 5th of February 2014 Ricoh announced they would exhibit a new model Pentax medium format digital at the CP+ 2014 Camera and Photo Imaging Show, tentatively titled the "645D 2014".

Features announced include a "latest, super-high-resolution CMOS image sensor" and a "tilt-type LCD monitor".

[5] The Pentax 645Z uses a 51.4 megapixel CMOS sensor and a 27-point autofocus system with two SD card slots in a weather sealed body.

The acronym "smc" stands for super multi-coated, a feature long found on higher-grade Pentax lens.

Abbreviations: Focus motor: screw drive (in camera) - SDM (Silent Drive Motor) Glass: AL (aspheric lens) - ED (extra low dispersion lens) Coating: smc (super multi coating) - HD (high definition coating) Sealing: AW (All Weather) Features: QS (Quick Shift, all DA & D FA lenses) - IF (Internal focusing) - LS (Lens Shutter), central shutter inside the lens enables a synchronized flash speed up to 1/500s |} VIDEO: 720p / 1080p / 4K