Comparison of Canon EF 200-400mm f/4L IS USM Extender 1.4X and Pentax SMC P-FA 250-600mm f/5.6 ED IF

Attribute	Pentax SMC P-FA 250-600mm f/5.6 ED IF ×	Canon EF 200-400mm f/4L IS USM Extender 1.4X ×
Filter Size (mm)	43	52
Closest Focus (m)	3.5	2
Magnification Ratio (x)	0.2	0.15
Length (mm)	442	366
Focus Details	Internal	Inner focusing; Full-time manual focus and ring USM; Ring USM, High-speed CPU and optimized AF algorithms; Power Focus mode; Focus Limiter
Diaphragm Blades Type	-	circular
Zoom System	Rotary with lock	Rotating
Image Circle	35mm	35mm
Focal Length (mm)	250.00 - 600.00	200.00 - 400.00
Name	Pentax SMC P-FA 250-600mm f/5.6 ED IF	Canon EF 200-400mm f/4L IS USM Extender 1.4X
Brand	Pentax	Canon
Weight (g)	5049	3620
Type	Telephoto Zoom	Telephoto Zoom
Lens Construction	18 elements in 16 groups, including 1 ED element	25 elements in 20 groups (incl. 1 rear filter); one fluorite and four UD lens elements
Notes	-	Built-in 1.4x extender (8 elements in 4 groups) switches to 280-560mm f/5.6 lens with 0.21x / 1.48 magnification ratio; 4-stop Image Stabilization
APS Equivalent	375 - 900mm	320 - 640mm
Aperture (f)	5.60 - 32.00	4.00 - 32.00
Diaphragm Blades	-	9
Diagonal Angle of View (degree)	4.10 - 9.90	6.20 - 12.00
Diameter (mm)	71	128