What is the closest focusing distance for this lens?

The closest focusing distance for the OM System 40 mm to 150 mm lens is 0.9 meters.

What is the maximum aperture of the OM System 40 mm to 150 mm lens?

The maximum aperture of the OM System 40 mm to 150 mm lens is F4 at the wide end and F5.6 at the telephoto end.

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OM System 40 mm to 150 mm - f/5.6 - f/4 - Varifocal Lens

M.Zuiko ED 40-150mm f4.0-5.6 R at a Glance: The latest generation of the M.Zuiko Digital ED 40-150 mm f4.0-5.6 R (35mm equivalent focal length: 80-300 mm) features a small, lightweight and flexible enough for everything from close-up portraits to long-distance scenes both indoors and outdoors.
For on-the-go: M.Zuiko everyday lenses offer a solution for every shooting situation, whether you need a convenient low-profile lens or a high-powered zoom.
Versatile and Affordable: Indoors or out-, this compact and lightweight telephoto zoom will help you capture all your stories.
Movie & Still Compatible: One of this lens’s most interesting features is the unique-to-Olympus Movie & Still Compatible mechanism, or MSC. This technology provides amazingly fast – and nearly silent – autofocus operation.