29 October 1981 Intercomparison Of Calculated And Measured Optical Transfer Function (OTF) For A Standard Triplet Lens
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Proceedings Volume 0274, Assessment of Imaging Systems II; (1981) https://doi.org/10.1117/12.931832
Event: Assessment of Imaging Systems: Visible and Infrared, 1981, Reading, United Kingdom
This paper discusses the design, manufacture and testing of a standard 100 mm f/4 triplet lens and its subsequent use for checking the accuracy of OTF measuring equipment. The tolerances on individual lens parameters, established in the design stage, correspond to a maximum uncertainty in MTF of ±0.05 at 20 c/mm (on-axis at full aperture). Precautions necessary during manufacture to achieve this level of agreement between theoretical and measured performance for the assembled lens are described. Interferometric methods were used to assess the accuracy of manufacture, the wavefront aberration so determined being compared with results of calculation from the basic lens design data. The OTF was derived from the measured wavefront data, confirming that performance within the ±0.05 MTF tolerance band had been achieved. The MTF was also measured directly, using the SIRA-BECK Eros IV equipment at RAE Farnborough, and compared with the calculated performance. One result of this comparison was to indicate the presence of an unsuspected source of error in the measurement procedure adopted for this particular test. This demonstrates very clearly the value of having a lens such as this available as a primary standard of reference, and that the lens amply fulfils its original purpose.
© (1981) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
K. G. Birch, K. G. Birch, A. C. Marchant, A. C. Marchant, "Intercomparison Of Calculated And Measured Optical Transfer Function (OTF) For A Standard Triplet Lens", Proc. SPIE 0274, Assessment of Imaging Systems II, (29 October 1981); doi: 10.1117/12.931832; https://doi.org/10.1117/12.931832

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