Archive for: DO

Patent: EF 400 f/4 DO IS II

Patent: EF 400 f/4 DO IS II

Another DO patent
We haven’t seen a new DO lens in a long time, but the patents haven’t stopped. It looks like Canon is continuing the R&D, I’d love to see it go somewhere.

Interpretation and self-description of the patent literature

  • Patent Publication No. 2013-64858
  • 2013.4.11 Release Date
  • Filing date 2011.9.16

Example 1

  • Focal length f = 392.12mm
  • Fno. 4.12
  • Half angle of ω = 3.16 °
  • Image height Y = 21.64mm
  • 262.14mm length lens
  • BF 69.97mm
  • Two fluorite
  • Materials and anomalous partial dispersion DOE to use, reduce the chromatic aberration
  • Refractive power of the diffractive surface
  • Strong, but can reduce the chromatic aberration of the element itself, flare increases
  • The weaker, other optical element DOE play a role
  • Refractive optical unit
  • DOE anomalous partial dispersion and bonding materials
  • DOE aspherical surface on the opposite side of the
  • Vibration control
  • Inner Focus

Source: [EG] | Canon EF 400 f/4 DO IS

36 Comments

Patent: 600 f/4 DO IS & 400 f/2.8 DO IS

Patent: 600 f/4 DO IS & 400 f/2.8 DO IS

Patent Time!
More diffractive optic patents from Canon. This time, another 600 f/4 IS DO lens and a 400 f/2.8 DO IS.

With the cost of the new super telephotos from Canon, I can’t imagine what new DO lenses would cost.

Continue reading for the patent breakdown….

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Patent: New Diffractive Optic Patents

Patent: New Diffractive Optic Patents

More DO Lenses?
A few patents in regards to diffractive optics have come about. 70-300 f/4.5-5.6 DO IS, 14 f/2.8 DO and a 600 f/4 DO IS.

Diffractive optic patents keep coming up, though no new products are being announced. It does appear Canon is invested in the technology and thinks there is a market for it. I am a big fan of the 400 DO and hope to see longer DO lenses in the future.

Read more about the patents after the break.

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Canon 16-35 f/2.8 DO Patent

Canon 16-35 f/2.8 DO Patent

More lens patents
This is an interesting DO patent from Canon. There seems to be a lot of them showing up, but no new DO products in a long while.

I’ve been told the lack of an A+ filterable wide angle from Canon for a full frame camera will be addressed sooner than later. Yes, there’s Zeiss, but most want AF.

Patent Publication No. 2011-145518

  • Release Date 2011.7.28
  • Filing date 2010.1.15

Example 1

  • Focal length f = 16.48 – 24.00 – 33.95 mm
  • Fno = 2.91
  • Half angle of 52.70 – 42.04 – 32.51 °
  • 4 aspherical surfaces
  • Zoom Ratio 2.06
  • Four-group zoom lens plus a negative sign
  • Second lens focusing is performed by Inner Focus
  • Solve various problems using the diffractive optical element
  • The astigmatism of the telephoto kept in order, to increase the refractive index of the positive lens
  • A high refractive index, chromatic aberration occurs
  • Aberration and astigmatism in the center of the telephoto image has a correlation, it is difficult to simultaneously correct
  • Made achromatic diffractive optical element, a positive lens astigmatism correcting high refractive index

Source [EG]

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23 Comments