http://www.canonrumors.com/patent-soft-focus-lens-designs-various-f...
Patent: Soft Focus Lens Designs, Various Focal Lengths
Canon has filed a patent spotted by Canon News for a variety of soft focus lenses. The most interesting of the bunch is a 70-200 f/4 full frame lens with a backfocus of 25mm, meaning it¡¯s not an EF mount lens.
35mm f/1.8 full frame EF Canon mount
Focal Length 33.75
F-Number 1.72
Image Height 21.64
Total Lens Length 132.93
BF 39.14
58mm f/1.4 full frame EF Canon mount
Focal Length 57.57
F-Number 1.43
Image Height 21.64
Total Lens Length 160.04
BF 40.43
105mm f/2.0 full frame EF Canon mount
Focal 103.2
F-Number 2.17
Image Height 21.64
Total Lens Length 123.79
BF 42.2
70-200 f/4 full frame BF of 25mm (not EF mount)
Focal 72.21 ? 194.06
F-Number 4.00
Image Height: 21.64
BF 25.98
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4 °³ÀÇij³í·»ÁîƯÇã°¡¹ß°ßµÇ¾ú´Ù. ±×·±µ¥ Èï¹Ì·Î¿î°ÍÀÌÀÖ´Ù¸é backfocus of 25mmÀÇ 70-200 f/4 full frame BF of 25mm (not EF mount)ƯÇã°¡Àִٴ°ÍÀÌ´Ù. ÀÌ°ÍÀº EF¸¶¿îÆ®°¡¾Æ´Ï¶ó´Â°ÍÀ¸·Î ij³íÇ®ÇÁ¹Ì·¯¸®½º¿ë 70-200 f/4·»ÁîÀÇƯÇãÀϱî?
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https://photo.popco.net/58191