This is based on one sample on one 645z body. Comments refer to the central area of the lens only, as for my images I don't much care if the corners go soft. I also don't concern myself much with distortion, as it's so easy to correct. Most all of my images are in good light at base ISO.

Relatively light and compact

Feels cheap it's so light; 82 mm filters are expensive

Pentax SMC FA 645 55-110mm f/5.6 Review

The Pentax SMC FA 645 55-110mm f/5.6 ($1,699.95) is a zoom lens for the company's 645D ( at Amazon) and 645Z medium format cameras. Its zoom ratio is a modest 2x, but it captures a slight wide angle to medium telephoto field of view, and considering that it covers a medium format image sensor, it's surprisingly light and compact. There are some compromises—the lens isn't sealed against dust and moisture like the digital 645 bodies are, it's not as crisp as pricier prime lenses, and it doesn't capture as much light as a prime. But given its price, and the versatility that a zooming design delivers, it's a solid choice for Pentax medium format owners. DesignThe 55-110mm ($1,499.00 at Amazon) is a sturdy lens, with a metal barrel, manual aperture ring, and rubberized zoom and focus control rings—but it doesn't have the o-ring seal at its base that completes the weather-resistant design of Pentax 645D and 645Z ($5,080.93 at Amazon) cameras. It measures 4.1 by 3.5 inches (HD) at its s...

The Pentax SMC FA 645 55-110mm f/5.6 brings the convenience of a zoom lens to medium format photography, but it's not as sharp as other lenses for the Pentax 645 system.

Light and compact; Minimal distortion; Even illumination; Focus clutch system

Not as sharp as other medium format lenses; Narrow maximum aperture; Aperture dims viewfinder; Design isn't weather resistant