Is the zeiss batis 40mm f 2 cf sharp wide open?

Here is what the site says about that.

From Zeiss Batis 40mm f/2 CF: Zeiss Batis 40mm f/2 CF: A prime lens by Zeiss for Full frame cameras, 40mm f/2. Specs - Maker: Zeiss - Focal length: 40mm (prime) - Maximum aperture: f/2 - Made for: Full frame sensors - Mounts: Sony E - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E): as marked, 40mm. - On APS-C (Sony E): like 60mm on full frame; f/2 gives about the depth of field ...

From Lenses: Aperture: The f-number says how wide the lens opens. Smaller numbers let in more light: f/1.8 lets in about ten times as much light as f/5.6, more than three stops. A wide aperture means faster shutter speeds in dim light and more background blur. Zooms with a constant aperture, like a 24-70mm f/2.8, keep the same exposure throughout the zoom range; cheaper zooms get darker as you zoom in.

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