• Hastings-Mounted-Positive-Achromatic-Lenses-1

Hastings Cemented
Achromatic Triplets

Achromatic lenses are a good choice for demanding maximum aberration control, as they offer substantially better performance than spherical singlets. Cemented achromatic doublets are sufficient for most applications at infinite conjugates, and cemented doublet pairs are ideal for finite conjugates. However, Achromatic triplets offer even better performance than achromatic doublets, as a matter of fact an achromatic triplet is the simplest lens that corrects all primary chromatic aberrations and delivers good on-axis and off-axis performance.

An achromatic triplets consist of a low-index crown center element cemented between two identical high-index flint outer elements. These triplets are capable of correcting both axial and laterial chromatic aberration, and their symmetric design provides enhanced performance relative to cemented doublets.

Hastings achromatic triplets are designed to provide an infinite conjugate ratio and are useful for focusing collimated beams and for magnification. In Contrast, Steinheil achromatic triplets are designed to provide a finite conjugate ratio and 1:1 imaging. Paralight Optics offers both Steinheil and Hastings achromatic triplets with an antireflection coating for the 400-700 nm wavelength range, please check the following graph for your references.



AR Coating:

AR Coated for the 400 - 700 nm Range (Ravg < 0.5%)


Ideal for Compensation of Lateral and Axial Chromatic Aberrations

Optical Performance:

Good On-Axis and Off-Axis Performance


Optimized for Infinite Conjugate Ratios


Common Specifications:


Reference Drawing for

Unmounted Hastings Achromatic Lens

f: Focal Length
WD: Working Distance
R: Radius of Curvature
tc: Center Thickness
te: Edge Thickness
H”: Back Principal Plane

Note: The focal length is determined from the back principal plane, which does not correspond with any physical plane inside the lens.



Ranges & Tolerances

  • Substrate Material

    Crown and Flint Glass Types

  • Type

    Hastings achromatic triplet

  • Lens Diameter

    6 - 25 mm

  • Lens Diameter Tolerance

    +0.00/-0.10 mm

  • Center Thickness Tolerance

    +/- 0.2 mm

  • Focal Length Tolerance

    +/- 2%

  • Surface Quality (Scratch - Dig)

    60 - 40

  • Surface Irregularity (Peak to Valley)

    λ/2 at 633 nm

  • Centration

    < 3 arcmin

  • Clear Aperture

    ≥ 90% of Diameter

  • AR Coating

    1/4 wave MgF2 @ 550nm

  • Design Wavelengths

    587.6 nm



This theoretical graph shows the percent reflectance of the AR coating as a function of wavelength for references.
♦ Reflectance Curve of Achromatic Triplet VIS AR Coating