Camera Mirror Lenses Part 1: Visual and Interferometric Testing

In this video I will discuss the visual and interferometric tests of camera mirror telephoto lenses. Contents: 0:00 intro 1:16 Vivitar f=800mm F:8 mirror lens 4:58 Sigma f=600mm F:8 mirror telephoto 7:34 Soligor f=500mm F:8 mirror lens 8:26 Explaining interferometry in auto-collimation 12:09 Actual interferometry measurement setup 14:58 About Strehl Ratio 17:15 Strehl ratio and aberrations of Vivitar 800mm mirror lens 18:18 Comparison with results of Sigma 600mm mirror lens 20:17 Extro EXTERNAL SOURCE LINKS: DFTfringe software download: https://github.com/githubdoe/DFTFringe/releases Dale Eason DFTfringe group: https://groups.io/g/Interferometry/topic/test_with_dftfringe/28806172 Other videos on DFTfringe software: https://www.youtube.com/watch?v=LU8PQGzEpQs https://www.youtube.com/watch?v=TqLjru6oKM4 https://www.youtube.com/channel/UCPj57WFSSLpVqPir7Im-kiw/videos https://youtu.be/WIl6FlUCHQg User experiences with the Vivitar 800mm mirror telephoto lens: https://www.bhphotovideo.com/c/product/885034-REG/Vivitar_v_800mr_800mm_Mirror_Lens_for.html/reviews https://www.amazon.com/Vivitar-800mm-Mirror-Lens-V-800MR/dp/B008G7ZPKE#customerreviews Syntax-Brillian Bankrupcy and Sakar aquirement: https://seekingalpha.com/article/66607-will-syntax-brillian-survive https://www.cnet.com/tech/tech-industry/sakar-acquires-vivitar-brand-and-ip/ https://www.optyczne.pl/1093-nowo%C5%9B%C4%87-Vivitar_na_sprzeda%C5%BC.html https://www.sakar.com/ Original Vivitar 800mm Solid Catadioptric: https://www.photo.net/forums/topic/509542-vivitar-series-1-600mm-f8-solid-catadioptric-telephoto-lens/ https://www.dpreview.com/news/3295932675/canon-patents-400mm-f5-6-catadioptric-mirror-lens Vivitar rebranding: https://mikeeckman.com/2016/12/vivitar-35es-1978/ Star field Foto (by Felix Mittermeier) https://www.pexels.com/photo/galaxy-space-957010/ Bokeh bird in garden photo (by kenetik): http://forum.mflenses.com/vivitar-series-1-600mm-f8-solid-cat-and-a-bird-in-the-garden-t69033.html Tommy Cooper photo: https://panorama.nl/artikel/174764/komiek-tommy-cooper-stierf-35-jaar-geleden-in-het-harnas End music: "Floating" performed by the Early Birds (recorded in Eindhoven in 2000). Did I forget to mention you above and are you a copyright owner? let me know and I will set it straight by linking to your original content in these credits.