|
Sigma 4.5mm F2.8 EX DC Circular Fisheye HSM Lens
The Sigma 4.5mm f/2.8 EX DC circular fisheye is a photographic lens manufactured by Sigma Corporation. It is a circular fisheye lens, designed to project a 180-degree field of view in all directions onto a circular image. It is the first such lens to provide the complete circular fisheye effect on crop factor digital SLR cameras, which do not have a full 36x24mm sensor. This lens is available in Canon, Nikon, Sigma, Pentax and Sony mounts. This lens projects a 13mm image circle, which fits nicely in a Micro Four Thirds system frame, but it must be adapted from one of the available APS-C mounts (listed above) in order to work on a Micro Four Thirds body. See also *List of Nikon compatible lenses with integrated autofocus-motor The following list of Nikon F-mount lenses with integrated autofocus motor includes only Nikon F-mount lenses which fully autofocus in all modes of all Nikon F-mount digital single-lens reflex cameras with and also ''without'' an autofocus moto ... * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma Corporation
is a Japanese company, manufacturing cameras, lenses, flashes and other photographic accessories. All Sigma products are produced in the company's own Aizu factory in Bandai, Fukushima, Japan. Although Sigma produces several camera models, the company is best known for producing high-quality lenses and other accessories that are compatible with the cameras produced by other companies. The company was founded in 1961 by Michihiro Yamaki, who was Sigma's CEO until his death at age 78 in 2012. Sigma products work with cameras from Canon, Nikon, Pentax, Sony, Olympus and Panasonic, as well as their own cameras. Sigma has also made lenses under the Quantaray name, which have been sold exclusively by Ritz Camera. Similarly, Sigma lenses were sold exclusively by the former Wolf Camera, but following the merger of Wolf and Ritz, both brands can be purchased. Sigma's digital SLRs, the SD9, SD10, SD14 and SD15, plus the latest SD1 are unusual in their use of the Foveon X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Motor
An ultrasonic motor is a type of piezoelectric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation (rotation or linear translation). Ultrasonic motors differ from other piezoelectric motors in several ways, though both typically use some form of piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials. The most obvious difference is the use of resonance to amplify the vibration of the stator in contact with the rotor in ultrasonic motors. Ultrasonic motors also offer arbitrarily large rotation or sliding distances, while piezoelectric actuators are limited by the static strain that may be induced in the piezoelectric element. One common application of ultrasonic motors is in camera lenses where they are used to move lens elements as part of the auto-focus system. Ultrasonic motors replace the noisier an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisheye Lens
A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens. Instead of producing images with straight lines of perspective ( rectilinear images), fisheye lenses use a special mapping ("distortion"; for example: equisolid angle, see below), which gives images a characteristic convex non-rectilinear appearance. The term ''fisheye'' was coined in 1906 by American physicist and inventor Robert W. Wood based on how a fish would see an ultrawide hemispherical view from beneath the water (a phenomenon known as Snell's window). Their first practical use was in the 1920s for use in meteorology to study cloud formation giving them the name "whole-sky lenses". The angle of view of a fisheye lens is usually between 100 and 180 degrees, although lenses covering up to 280 degrees exist (see below). Their focal lengths ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Lens
A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically. There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to a camera, or it might be interchangeable with lenses of different focal lengths, apertures, and other properties. While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise. Some aberrations will be present in any lens system. It is the job of the lens designer to balance these and produce a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crop Factor
In digital photography, the crop factor, format factor, or focal length multiplier of an image sensor format is the ratio of the dimensions of a camera's imaging area compared to a reference format; most often, this term is applied to digital cameras, relative to 35 mm film format as a reference. In the case of digital cameras, the imaging device would be a digital sensor. The most commonly used definition of crop factor is the ratio of a 35 mm frame's diagonal (43.3 mm) to the diagonal of the image sensor in question; that is, CF=diag35mm / diagsensor. Given the same 3:2 aspect ratio as 35mm's 36 mm × 24 mm area, this is equivalent to the ratio of heights or ratio of widths; the ratio of sensor areas is the square of the crop factor. The crop factor is sometimes used to compare the field of view and image quality of different cameras with the same lens. The crop factor is sometimes referred to as the focal length multiplier ("Film") since multiplying a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Single-lens Reflex Camera
A digital single-lens reflex camera (digital SLR or DSLR) is a digital camera that combines the optics and the mechanisms of a single-lens reflex camera with a digital imaging sensor. The reflex design scheme is the primary difference between a DSLR and other digital cameras. In the reflex design, light travels through the lens and then to a mirror that alternates to send the image to either a prism, which shows the image in the viewfinder, or the image sensor when the shutter release button is pressed. The viewfinder of a DSLR presents an image that will not differ substantially from what is captured by the camera's sensor as it presents it as a direct optical view through the main camera lens, rather than showing an image through a separate secondary lens. DSLRs largely replaced film-based SLRs during the 2000s. Major camera manufacturers began to transition their product lines away from DSLR cameras to mirrorless interchangeable-lens cameras (MILC) beginning in the 2010s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canon EF Lens Mount
The EF lens mount is the standard lens mount on the Canon EOS family of SLR film and digital cameras. EF stands for "Electro-Focus": automatic focusing on EF lenses is handled by a dedicated electric motor built into the lens. Mechanically, it is a Bayonet mount, bayonet-style mount, and all communication between camera and lens takes place through electrical contacts; there are no mechanical levers or plungers. The mount was first introduced in 1987. Canon claims to have produced its 100-millionth EF-series interchangeable lens on 22 April 2014. History The EF mount replaces its predecessor, the Canon FD, FD mount. The standard autofocus lens mounting technology of the time used a motor in the camera body to drive the mechanics of the focus helicoid in the lens by using a transfer lever. The key innovation of the EF series was to use a motor inside the lens itself for focusing. This allowed for autofocusing lenses which did not require mechanical levers in the mount mechanis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nikon F-mount
The Nikon F-mount is a type of interchangeable lens mount developed by Nikon for its 35mm format single-lens reflex cameras. The F-mount was first introduced on the Nikon F camera in 1959, and features a three-lug bayonet mount with a 44mm throat and a flange to focal plane distance of 46.5mm. The company continues, with the 2020 D6 model, to use variations of the same lens mount specification for its film and digital SLR cameras. History The Nikon F-mount is one of only two SLR lens mounts (the other being the Pentax K-mount) which were not abandoned by their associated manufacturer upon the introduction of autofocus, but rather extended to meet new requirements related to metering, autofocus, and aperture control. The large variety of F-mount compatible lenses makes it the largest system of interchangeable flange-mount photographic lenses in history. Over 400 different Nikkor lenses are compatible with the system. The F-mount is also popular in scientific and industrial a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma SA Mount
The Sigma SA-mount is a lens mount by the Sigma Corporation of Japan for use on their autofocus single-lens reflex and mirrorless cameras. It was introduced with the '' SA-300'' in 1992. Originally, the SA-mount was a dual-bayonet mount with inner (SA-IB) and outer (SA-OB) bayonets, the latter being a feature intended to mount heavy telephoto lenses, but never utilized by Sigma and consequently dropped with the release of the ''SD14'' in 2007. There were two precursors to the introduction of SA-mount cameras, the manual-focus Sigma Mark-I in 1976, which still featured a M42 screw lens mount, and the '' SA-1'' of 1983 with Pentax K-mount. Mechanically, the (inner) SA-mount is similar to the Pentax K-mount as well, but with a flange focal distance of 44.00 mm, identical to that of the Canon EF-mount. Like the EF-mount, the SA-mount uses electrical communication between body and lens, and in fact uses the same signalling lines and protocol as the EF-mount, despite the physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentax K Mount
The Pentax K-mount, sometimes referred to as the "PK-mount", is a bayonet lens mount standard for mounting interchangeable photographic lenses to 35 mm single-lens reflex (SLR) cameras. It was created by Pentax in 1975, and has since been used by all Pentax 35 mm and digital SLRs and also the MILC Pentax K-01. A number of other manufacturers have also produced many K-mount lenses and K-mount cameras. Mounts The Pentax K-mount has undergone a number of evolutions over the years as new functionality has been added. In general, the term K-mount may refer to the original K-mount, or to all its variations. Originally designed by Zeiss for an alliance with Pentax, it was intended to be a common lens mount for a proposed series of cameras and lenses. However, the plan failed to work out and the two firms parted company amicably, but Pentax retained the lens mount and at least one Zeiss lens design for its own use. K-mount The original K-mount is a simple bayonet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sony α
Sony α (the lower case to Greek letter alpha, often transliterated as ''Sony Alpha'') is a digital camera system introduced on 5 June 2006. It uses and expands upon Konica Minolta camera technologies, including the Minolta AF SLR lens mount, whose assets were acquired by Sony after the end of Konica Minolta's photography operations in early 2006. Sony also has an 11.08% ownership stake in Japanese lens manufacturer Tamron, which is known to have partnered with Konica Minolta and Sony in the design and manufacture of many zoom lenses. Prior to the acquisition by Sony, the ''α'' branding had already been used on the Japanese market by Minolta for their AF camera system (marketed as "Dynax" in Europe, and "Maxxum" in North America). Sony adopted the name " A-mount system" for the Minolta AF lens mount, which has been retained in their new SLR range. Sony's entry into the DSLR market dates back to July 2005 where a joint venture with Konica Minolta would hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
