Is the ttartisan 90mm f 1 25 sharp wide open?

Here is what the site says about that.

From TTArtisan 90mm f/1.25: TTArtisan 90mm f/1.25: A prime lens by TTArtisan for Full frame cameras, 90mm f/1.2. Specs - Maker: TTArtisan - Focal length: 90mm (prime) - Maximum aperture: f/1.2 - Made for: Full frame sensors - Mounts: Sony E, Nikon Z, Canon RF, L-Mount, Leica M - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Sony E, Nikon Z, Canon RF, L-Mount, Leica M): as marked, 90mm. - ...

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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