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EXCERPT page containing first few paragraphs. 2023-03-29 05:41:02

Coastal Optics
60mm f/4 UV-VIS-IR APO macro

Lens Designer Notes

These notes are straight from the lens designer, J. Brian Caldwell, Ph.D., of Caldwell Photographic Inc, in response to questions posed by Lloyd Chambers of Italicized type indicates lens designer comments.

Field Curvature

The lens was optimized for a flat image plane for both distant and close object distances, and there is very little to be gained by allowing the image plane to curve, or equivalently considering a curved object plane. If you look at the MTF curves for infinity focus that I put in the online brochure you'll see that at f/5.6 there is essentially no drop in performance over the DX format (~29mm diagonal), and only a very small performance drop in the outer parts of the FX format (43.2mm diagonal). So, at f/5.6 you probably will have difficulty detecting any field curvature at all.

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Diglloyd DAP is DSLR-oriented, but also contains workflow and other topics. Much of the focus is on Canon and Nikon but also Pentax and Pentax medium format.

Special emphasis is placed on lens evaluation, focusing on Canon and Nikon and Sigma lenses, but with a few others like Rokinon/Samyang.

  • Make better images by learning how to get the best results right away.
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  • Workflow discusses image organization, raw conversion and post processing. Many examples show processing parameters for direct insight into how the image was converted.
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  • Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
  • Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.

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