This is a Samyang-made lens that has a maximum focal length of 100 mm and a minimum focusing distance of 0.307 m. The lens has a maximum ƒ/3.1 aperture and a minimum ƒ/32.
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Samyang Lens for Nikon T3.1 100 mm Black
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Samyang 7855 100mm MAC T3.1 VDSLR ED UMC Macro Lens - Nikon Fit