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Canon EF-S 17–55mm Lens
The Canon EF-S 17–55mm 2.8 IS USM is a standard zoom lens for Canon digital single-lens reflex cameras with an EF-S lens mount. The field of view has a 35 mm equivalent focal length of 27–88mm. Reception Praise It is praised as "one of the best general/multi-purpose lenses available", and ideal for available light photography on a Canon APS-C camera. The fast 2.8 aperture, combined with 3-stop image stabilization, makes the 17–55 very useful in low light compared to an unstabilized 3.5–5.6 Canon EF-S 18–55mm lens, which is a frequent kit lens, and thus the 17–55 is much more suited for hand holding and available-light photography. Newer versions of the 18–55 kit lens include 4-stop image stabilization, but remain slower aperture, partly addressing this concern. Criticism This lens has been criticized by one review as prone to flare when the sun is in the frame. The 17–55 suffers from vignetting at 2.8 of 0.5–1 EV throughout the focal range, though current ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon (company)
is a Japanese multinational corporation headquartered in Ōta, Tokyo, Japan, specializing in optical, imaging, and industrial products, such as lenses, cameras, medical equipment, scanners, printers, and semiconductor manufacturing equipment.Corporate Profile " ''Canon''. Retrieved on 13 January 2009. Canon has a primary listing on the and is a constituent of the Core30 and index. It has a secondary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposure Value
In photography, exposure value (EV) is a number that represents a combination of a camera's shutter speed and f-number, such that all combinations that yield the same exposure have the same EV (for any fixed scene luminance). Exposure value is also used to indicate an interval on the photographic exposure scale, with a difference of 1 EV corresponding to a standard power-of-2 exposure step, commonly referred to as a stop. The EV concept was developed by the German shutter manufacturer in the 1950s ( Gebele 1958; Ray 2000, 318). Its intent was to simplify choosing among equivalent camera exposure settings by replacing combinations of shutter speed and ''f''-number (e.g., 1/125 s at ''f''/16) with a single number (e.g., 15). On some lenses with leaf shutters, the process was further simplified by allowing the shutter and aperture controls to be linked such that, when one was changed, the other was automatically adjusted to maintain the same exposure. This was especially he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dpreview
''Digital Photography Review'', also known as ''DPReview,'' is a website about digital cameras and digital photography, established in November 1998. The website provides comprehensive reviews of digital cameras, lenses and accessories, buying guides, user reviews, and forums for individual cameras, as well as general photography forums. The website also has a database with information about individual digital cameras, lenses, printers and imaging applications. Originally based in London, ''Digital Photography Review'' and most of its team relocated to Seattle, Washington, in 2010. It is currently owned by Amazon. Main features ''DPReview'' has regularly published thorough, technically orientated camera reviews since the website launched in 1998. The content and scope of the reviews have changed over time, but the basic formula (extensive descriptions of controls and menus, consistent, repeatable studio tests, side-by-side pixel-level comparisons) has remained unchanged since ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF 28-90mm Lens
The Canon EF 28–90mm 4–5.6 is a full frame SLR zoom lens, also often included as a kit lens with Canon EOS film cameras. The maximum aperture is 4 at 28mm, reducing to 5.6 at 90mm. When set to 90mm, this will create a moderate amount of background blur for portrait photography. There are several versions of this lens. They all share an identical optical design of 10 lenses in 8 groups and 5 aperture petals. Versions I and II were available with either a DC auto focus motor or an ultrasonic USM motor. All other differences are purely cosmetic. All versions had plastic lens mounts and barrels. Some were available in silver or black colour. The lens is a very lightweight design, and has fast auto focus even without USM. Image quality suffers, though, particularly between 28–35mm and 80–90mm, and there is heavy vignetting when used wide open. For digital EOS cameras with APS-C sensors, the EF-S 18–55mm lens covers the same focal length range. This is due to crop fact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF 24–70mm Lens
The Canon EF 24–70mm lens is a family of professional EF mount wide-to- normal zoom lenses manufactured and sold by Canon. The first of the family, the EF 24–70mm f/2.8L, was introduced in 2002 to replace the well-regarded 28–70mm f/2.8L. Two later versions were announced in 2012. The first of these, the EF 24–70mm f/2.8L II, was announced by Canon in February,Canon EF 24-70 f/2.8L II Announced « Canon Rumors Canonrumors.com (7 February 2012). Retrieved 2013-10-04. but would not ship to customers until September of that year. This lens replaced the Mk I, and had an MSRP of US$2299 when introduced. The latest member of the family is the EF 24–70mm f/4L IS USM, which became available in January 2013. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF 17–40mm Lens
The EF 17–40mm 4L USM lens is a wide-angle lens made by Canon Inc. The lens has an EF mount to work with the EOS line of cameras. Other than the front element, it is sealed against dust and water, and features a diaphragm which remains nearly circular from 4 to 8. It is one of the few Canon photo lenses that are parfocal. Audience The 17–40mm is the least expensive of Canon's current wide-angle zooms for full-frame bodies, with the EF 16–35mm 4L IS USM and EF 11–24mm 4L USM being more expensive, and the EF 16–35mm 2.8L USM being both faster and more expensive. Weighing 475 g and measuring 83.5 mm x 96.8 mm, it is a popular choice with many photographers because of its light and compact size. A member of the L-series, the 17–40mm is a good substitute for the 16–35mm 2.8 lens, which is heavier and costs approximately twice as much. Canon now sells an image-stabilized 16–35mm 4 lens for about $300 more than the 17–40. This lens is also a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF-S 15–85mm Lens
The Canon EF-S 15–85mm f/3.5–5.6 IS USM is a standard zoom lens for Canon digital single-lens reflex cameras with an EF-S lens mount. The field of view has a 35 mm equivalent focal length of 24–136mm. The EF-S mount was specifically designed for APS-C cameras. It is the higher end kit lens for the Canon EOS 7D The Canon EOS 7D is an APS-C digital single-lens reflex camera made by Canon. It was announced on 1 September 2009 with a suggested retail price of US$1,699. Among its features are an 18.0 effective megapixel CMOS sensor, HD video recording, its .... References External links Canon EF-S 15–85mm – Canon UK [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF-S 17–85mm Lens
The Canon EF-S 17–85mm 4–5.6 IS USM is a standard zoom lens for Canon digital single-lens reflex cameras with an EF-S lens mount and image stabilization. The EF-S designation means it can only be used on EOS cameras with an APS-C sensor released after 2003. The field of view has a 35 mm equivalent focal length of 27.2–136mm, and it is roughly equivalent to the Canon EF 28-135mm lens on a 35mm film SLR. Despite the word "macro" being present on the lens body (as visible in the infobox image), this lens is not capable of true 1:1 macro photography Macro photography (or photomacrography or macrography, and sometimes macrophotography) is extreme close-up photography, usually of very small subjects and living organisms like insects, in which the size of the subject in the photograph is grea .... The 17–85mm was bundled as a kit lens with the EOS 30D, EOS 40D, EOS 50D and EOS 60D. It was also packaged with the EOS 400D (known as the Digital Rebel XTi in North Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon L Lens
Canon or Canons may refer to: Arts and entertainment * Canon (fiction), the conceptual material accepted as official in a fictional universe by its fan base * Literary canon, an accepted body of works considered as high culture ** Western canon, the body of high culture literature, music, philosophy, and works of art that is highly valued in the West * Canon of proportions, a formally codified set of criteria deemed mandatory for a particular artistic style of figurative art * Canon (music), a type of composition * Canon (hymnography), a type of hymn used in Eastern Orthodox Christianity. * ''Canon'' (album), a 2007 album by Ani DiFranco * ''Canon'' (film), a 1964 Canadian animated short * ''Canon'' (game), an online browser-based strategy war game * ''Canon'' (manga), by Nikki * Canonical plays of William Shakespeare * ''The Canon'' (Natalie Angier book), a 2007 science book by Natalie Angier * ''The Canon'' (podcast), concerning film Brands and enterprises * Canon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrel Distortion
In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image. It is a form of aberration in optical systems, optical aberration. Radial distortion Although distortion can be irregular or follow many patterns, the most commonly encountered distortions are radially symmetric, or approximately so, arising from the symmetry of a photographic lens. These ''radial distortions'' can usually be classified as either ''barrel'' distortions or ''pincushion'' distortions. Mathematically, barrel and pincushion distortion are quadratic function, quadratic, meaning they increase as the ''square'' of distance from the center. In mustache distortion the quartic function, quartic (degree 4) term is significant: in the center, the degree 2 barrel distortion is dominant, while at the edge the degree 4 distortion in the pincushion direction dominates. Other distortions are in principle possible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus ''shift''). Longitudinal aberration is typical at long focal lengths. Transverse aberration occurs when different wavelengths are focused at different positions i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vignetting
In photography and optics, vignetting is a reduction of an image's brightness or saturation toward the periphery compared to the image center. The word ''vignette'', from the same root as ''vine'', originally referred to a decorative border in a book. Later, the word came to be used for a photographic portrait that is clear at the center and fades off toward the edges. A similar effect is visible in photographs of projected images or videos off a projection screen, resulting in a so-called "hotspot" effect. Vignetting is often an unintended and undesired effect caused by camera settings or lens limitations. However, it is sometimes deliberately introduced for creative effect, such as to draw attention to the center of the frame. A photographer may deliberately choose a lens that is known to produce vignetting to obtain the effect, or it may be introduced with the use of special filters or post-processing procedures. When using superzoom lenses, vignetting may occur all alo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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