Focal Length: 15-35mm Macro Ratio: 0.22-0.47 Diopter: -1.0 ~ -0.3 Lens Construction: 7 groups 8 elements Diopter adjustment: +1.3/-2.8 Parllax distance : 1m Eye point: 15mm from the last element Eye point: 12.5mm from eyepiece Size: 42.5 x 49.5 x 65.4mm Weight: 98g Focal Length indication: 15, 18, 21, 25, 28, 35m