Comparison of Carl Zeiss 18mm f/3.5 Distagon T* 3.5/18 and Tokina 17mm f/3.5 AT-X 17 AF PRO Aspherical

Attribute	Carl Zeiss 18mm f/3.5 Distagon T* 3.5/18 ×	Tokina 17mm f/3.5 AT-X 17 AF PRO Aspherical ×
Diagonal Angle of View (degree)	99.00	103.70
Notes	Available SLR mounts: Canon EF (ZE), Nikon F (ZF, ZF.2), Pentax K (ZK). Lens shade included. Nikon ZF.2 version includes CPU interface for autoexposu	Available AF Mounts: Canon, Minolta, Nikon; Included Accessories: Flower type lens hood
Aperture (f)	3.50 - 22.00	3.50 - 22.00
Magnification Ratio (x)	0.083	0.11
Filter Size (mm)	82	77
Type	Wide Prime	Wide Prime
Closest Focus (m)	0.3	0.25
APS Equivalent	1.5x: 27mm	1.5x: 25.5mm; 1.6x: 27.2mm
Lens Construction	13 elements in 11 groups	11 elements in 9 groups, including 1 aspherical element
Image Circle	35mm	35mm
Focal Length (mm)	18.00	17.00
Brand	Carl-zeiss	Tokina
Name	Carl Zeiss 18mm f/3.5 Distagon T* 3.5/18	Tokina 17mm f/3.5 AT-X 17 AF PRO Aspherical
Weight (g)	470	435
Diameter (mm)	87	84
Length (mm)	84	57
Diaphragm Blades	-	7
Focus Details	Manual focus only	Internal with Focus Clutch mechanism