Four Thirds Zoom Wildlife lenses that have a f/4 or faster aperture

"I am delighted with this 140-600mm lense as it enables me to get close shots of birds and wildlife and has great clarity and sharpness for a moderately priced lense." bhphotovideo.com

	Aperture	f/4			Diameter	80 mm
	Weight	0.6 kg			Fixed aperture	No
	Length	127 mm			Max focal length	300 mm
	Zoom range	4.3x			Min focal length	70 mm

"Excellent lens for sport and fast action. The external zooming makes it a bit fragile if you're shooting in crowds or potentially damaging environments." bhphotovideo.com

	Aperture	f/2.8			Diameter	87 mm
	Weight	1 kg			Fixed aperture	No
	Length	157 mm			Max focal length	200 mm
	Zoom range	4x			Min focal length	50 mm

"Great clear shots, good focus and great zoom range. Produces really good sharp images" bhphotovideo.com

Quite short 72 mm

Small diameter 66 mm

Very light 220 g

	Aperture	f/4			Diameter	66 mm
	Weight	220 g			Fixed aperture	No
	Length	72 mm			Max focal length	150 mm
	Zoom range	3.8x			Min focal length	40 mm

"One of the major benefits to the lens is that we have no need to switch cameras, or lens because it comes in to 18mm but zooms out to 180mm." bhphotovideo.com

Great zoom range 10x

	Aperture	f/3.5			Diameter	78 mm
	Weight	435 g			Fixed aperture	No
	Length	85 mm			Max focal length	180 mm
	Zoom range	10x			Min focal length	18 mm

"It provides outstanding sharp photos at long distances; with the f2.8 stopping action (surfers; shore objects from a ship a mile or two off shore). I have used it at sporting events and have even used it for some astronomy work (great for the moon)." bhphotovideo.com

Fixed aperture The same maximum aperture at all focal lengths

	Aperture	f/2.8			Diameter	125 mm
	Weight	3.3 kg			Fixed aperture	Yes
	Length	277 mm			Max focal length	250 mm
	Zoom range	2.8x			Min focal length	90 mm