Helios 44-2 58 mm f/ 2 is lens based on the Biotar 2/58 lens (Carl Zeiss Jena). Helios 44-2 58mm f/2 M42 Square Bokeh. In the center of the image, the lens is quite sharp even at f / 2.0. Like other lenses in the HELIOS-44 family, the 44-2 version twists the background (the legendary 'swirly bokeh' of the Helios).
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