The Pentax smc FA 645 33-55mm f/4.5 AL Lens is a wide-angle zoom lens designed for use with medium format Pentax 645 mount cameras. It features an aperture range of f/4.5-32 and has a 35mm equivalent focal length of 26-43.5mm, providing a very useful range of wide-angle lengths. This lens in particular utilizes two aspherical elements that greatly reduce distortion, field curvature, and coma aberrations common with wide angle lenses.
The 33-55mm features a lens construction of 11 elements in 8 groups, including some high refraction low-dispersion glass. To maintain image quality, it uses a 3-group floating zoom to reduce field curvature throughout the range. Also, the 33-55mm has a minimum focus distance of 15.7".
For smooth out-of-focus areas, the lens has an eight blade aperture diaphragm. Additionally, it features an 82mm front filter thread.
Focal Length | 33 to 55mm |
Maximum Aperture | f/4.5 |
Minimum Aperture | f/32 |
Lens Mount | Pentax 645 |
Angle of View | 53° to 80° |
Minimum Focus Distance | 15.75" / 40.01 cm |
Maximum Magnification | 0.21x |
Optical Design | 11 Elements in 8 Groups |
Diaphragm Blades | 8 |
Focus Type | Autofocus |
Image Stabilization | No |
Filter Size | 82 mm (Front) |
Dimensions (ø x L) | 3.46 x 4.09" / 88 x 104 mm |
Weight | 1.29 lb / 585 g |
Package Weight | 2.04 lb |
Box Dimensions (LxWxH) | 6.25 x 5.5 x 5.1" |