Achromatic Doublet Lens, Visible, 50.8 mm, 250 mm EFL, 400-700 nm

  • Lens Type
    Achromatic Doublet
  • Diameter
    50.8 mm
  • Antireflection Coating
    400-700 nm
  • Coating Type
    Visible Single-Layer MgF2
  • Damage Threshold
    1.0 J/cm2 @ 1064 nm, 10 ns , 10 Hz
  • Transmission
    T>95%
  • Lens Material
    N-BK7/N-SF5
  • Surface Quality
    40-20 scratch-dig
  • Surface Accuracy, Irregularity
    λ/4
  • Surface Accuracy, Power
    1.5 λ  
  • Effective Focal Length (EFL)
    250 mm
  • Back Focal Length (BFL)
    243.9 mm  
  • F/#
    4.9  
  • Radius of Curvature (R)
    151.578 mm  
  • Radius 2
    -112.149 mm
  • Radius 3
    -335.971 mm
  • Edge Thickness (Te)
    9.7 mm  
  • Center Thickness (Tc)
    12.83 mm  
  • Thickness, Center 1
    8.5 mm  
  • Thickness, Center 2
    4.33 mm  
  • Orientation
    Steepest convex surface should face the infinite conjugate
  • Design Wavelengths
    589 nm
  • Centration
    ≤3 arc min
  • Diameter Tolerance
    +0/-0.1 mm
  • Focal Length Tolerance
    ±2.0%
  • Center Thickness Tolerance
    ±0.4 mm
  • Clear Aperture
    90% of central diameter
  • Cleaning