Voigtl nder color skopar vintage line 21mm f 3 5 aspherical vs leica 21mm f 3 4?

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From Voigtländer Color-Skopar Vintage Line 21mm f/3.5 Aspherical: Voigtländer Color-Skopar Vintage Line 21mm f/3.5 Aspherical: A prime lens by Voigtländer for Full frame cameras, 21mm f/3.5. Specs - Maker: Voigtländer - Focal length: 21mm (prime) - Maximum aperture: f/3.5 - Made for: Full frame sensors - Mounts: Leica M - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Leica M): as marked, 21mm. Cameras it fits - Leica M9: Full frame - Leica M9-P: Full frame - [Leica ...

From Focal length converter: How it works: Multiply the focal length by the sensor's crop factor to get its full-frame equivalent. To go between two smaller formats, multiply by the first crop factor and divide by the second. Crop factors are measured on the sensor diagonal, so formats with a different shape (4:3 against 3:2) frame slightly differently across the width.

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