Bi-Concave Lens, N-BK7, 12.7 mm Diameter, -25 mm EFL, Uncoated

  • Lens Shape
    Bi-Concave
  • Diameter
    12.7 mm
  • Lens Material
    N-BK7
  • Antireflection Coating
    Uncoated
  • Surface Quality
    40-20 scratch-dig
  • Surface Accuracy, Irregularity
    λ/4
  • Surface Accuracy, Power
    1.5 λ  
  • F/#
    -1.9  
  • Effective Focal Length (EFL)
    -25 mm  
  • Back Focal Length (BFL)
    -25.81 mm  
  • Radius of Curvature (R)
    -26.259 mm  
  • Edge Thickness (Te)
    3.76 mm  
  • Center Thickness (Tc)
    2.5 mm  
  • Principal Plane 1 (P1)
    0.81 mm  
  • Principal Plane 2 (P2)
    -0.81 mm  
  • Design Wavelength
    589 nm
  • Centration
    ≤3 arc min
  • Chamfers
    0–0.8 mm face width
  • Chamfers Angle/Tolerance
    45° ±15°, typical
  • Focal Length Tolerance
    ±1 %
  • Diameter Tolerance
    +0/-0.1 mm
  • Center Thickness Tolerance
    ±0.1 mm
  • Clear Aperture
    ≥central 90% of diameter
  • Cleaning