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1200mm f/10 lens design to cover 12x20 format with high image quality

jonesmi

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Jan 11, 2026
Messages
9
Location
Texas
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Multi Format
This might be interesting to some. I designed this very large and heavy 1200mm f/10 lens to see how sharp I could get it over a 12"x20" format and 0.49-0.63µm spectral band, when designing with modern optical design software (Zemax) and modern optical glasses. 50% encircled energy (EE) blur circle diameters range from about 14µm at center to 22µm at the corners going from infinity to 50 foot object distance. This shows the point spread functions at five different field points in the 12x20" format from center to corner.
 

Attachments

  • 1200mm f10 blue-red correction infinity to 50 feet.jpg
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  • 1200mm f10 blue-red correction infinity PSF analysis.jpg
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For those of you that read MTF plots, these are performance analysis metrics for the 1200mm f/10 lens I designed.
 

Attachments

  • 1200mm f10 blue-red correction diffraction encircled energy.jpg
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  • 1200mm f10 blue-red correction infinity MTF over FOV.jpg
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And finally, here's how to make the 1200mm f/10 lens. Feel free to key it into CodeV, Zemax, Oslo, ATMOS or whatever optical analysis code you're familiar with.
This lens is so large, heavy and expensive to make I have no doubt at all that it will never be made. My fun was in just designing it to see how sharp I could get it. It would be absolutely fascinating to compare the image sharpness of historic 1200mm lenses to this design.
 

Attachments

  • 1200mm f10 blue-red correction infinity to 50 feet - prescription.jpg
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