This is a Panasonic-made lens that has a 0.25 magnification ratio. The lens has a maximum ƒ/4 aperture and a minimum ƒ/22.
From London Camera Exchange
Panasonic Leica DG Vario-Elmar 100-400mm F4.0-6.3 II ASPH. POWER O.I.S. (H-RSA100400E)
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