12/31/2023 0 Comments Lens diffraction in photographyRing-shaped flare is significantly reducedįurthermore, the gapless dual-layered DO lens is arranged further inside the lens to make it less subject to unnecessary light outside the screen which can cause flaring in backlight. Gapless dual-layered Diffractive Optics element As a result, light can enter without any loss, making it possible to reduce the occurrence of ring-shaped flare. The diffraction lattices are thus adhered to each other, with no layer of air between them. The gapless dual-layered diffractive optical elements features new material that makes up each diffraction lattice and the elimination of air layer. In order to solve this issue, Canon incorporated the newly developed 3rd generation DO Lens: Gapless dual-layered diffractive optical element into the new generation EF 400mm f/4 DO IS II USM. Because of this air layer and the characteristics of the material that made up the diffraction lattice, when there were bright light sources inside the screen, ring-shaped diffractive flaring would occur centered around the light sources, which degrades the image quality. With the 1st generation dual-layer DO lens, there is a layer of air inserted between the diffraction lattices. Reduction of ring-shaped diffractive flare The 3rd Generation DO Lens:Gapless dual-layered diffractive optical element The 3rd Generation DO Lens:Gapless dual-layered diffractive optical elements In addition, by partially changing the interval of the diffractive lattice (the spacing of the lattice) of the DO lens, an effect identical to that of an aspherical lens could be achieved, compensating for a variety of issues, such as spherical aberration.Ĭompared to a 400 mm f/4 lens designed with conventional methods, the overall length of 400mm f/4 DO lens was reduced by approx. By implementing an appropriate DO lens, it is possible to cancel out the chromatic aberration. Raised, and the lens elements are placed closer together in order to make the whole lens more compact, the chromatic aberration degenerates to a remarkableĭegree. As normal lenses with conventional refractive optics are reduced in size, the refractive power of each lens element is On the other hand, the characteristics of DO lens help to create compact and lightweight super telephone lens. If they are combined, they cancel out one another’s chromatic aberration, making possible an effective chromatic aberration correction.Ĭhromatic aberration that occurs with existing refractive optical elementsĬhromatic aberration on the DO lens is reversed with a refractive lensĪ combination of two forms an image with no chromatic aberration.Ĭompact Super Telephoto lens with DO Lens This is because the order of the chromatic aberration is reversed with a refractive lens and a diffractive optical element. The spacing of the lattice is from a few millimeters to a few dozen micrometers, and the manufacturing requires subtle and high precision technology.Ĭhromatic Aberration Correction with DO Lensĭiffractive optical elements attracted much attention for their ability to adjust forĬhromatic aberration better than UD or fluorite lenses. The diffraction lattices are a few micrometers thick (1 micrometer = 0.001millimeter). It is composed of spherical glass lenses and special plastic diffraction lattices. Taking advantage of this phenomenon, the Canon DO lens controls the path of light. When light passes through the edge of an obstacle, it has the characteristic of going around to the back side of the obstacle, known as “diffraction”. This lens is optimal for situations where it will be carried for lengthy periods such as mountain climbing, or nature photography.ĮF 400mm f/4 DO IS II USM that incorporates the newly developed 3rd generation gapless dual-layered diffractive optical element.Ĭanon DO Lens (Diffraction Optics Element)Ĭanon has successfully launched the compact and lightweight EF 400mm f/4 DO IS USM super telephoto lens in 2001, the first lens manufacturer to incorporate DO element in photographic lens. The gapless dual-layered diffractive optical element aims to improve the diffraction flare issue found in existing DO lens, bringing very high image quality while also being compact and lightweight. In September 2014, Canon announced the EF 400mm f/4 DO IS II USM compact super telephoto lens that incorporates the newly developed gapless dual-layered diffractive optical element.
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