Complex sentence: Early Minox cameras, with the Complan lens, held the negative in an arc to improve the sharpness of the image to the edge of the frame, and the corresponding Minox enlarger holds the negative in this same curve.
Split into simpler sentences: Early Minox cameras held the negative in an arc to improve the sharpness of the image to the edge of the frame from the Complan lens. The corresponding Minox enlarger holds the negative in this same curve.