| 摘要 |
<p>A fast photographic lens system comprises a first lens having a positive refractive power, a convexshaped outer face and a flat inner face; a second lens having a positive refractive power, a convex-shaped outer face and a concave-shaped inner face; a third lens having a negative refractive power, a slightly convex-shaped outer face, and a concave-shaped inner face; a fourth lens having a negative refractive power and a concave-shaped inner face; a fifth lens, joined with the fourth lens, and having a positive refractive power, a relatively flat inner face and a convexshaped outer face; a sixth lens having a positive refractive power, a slightly concave-shaped inner face and a convex-shaped outer face; and a seventh lens, having both convex-shaped inner and outer faces.</p> |
