Diffractive optics Canon EF lens mount
the green-ringed ef 70–300 mm f/4.5–5.6 usm
diffractive optics (do) special lens elements used in lenses. lenses smaller , lighter , better @ handling chromatic aberration, compared conventional lenses of similar focal length , aperture value. more expensive make. ef 400 mm f/4 usm, updated mark ii version, , ef 70–300 mm f/4.5–5.6 usm contain elements. lenses have green ring on barrel.
Comments
Post a Comment