Tokina Lens AT-X124ProDX Mark 2 (Canon) Tokina Lens AT-X124ProDX Mark 2 (Canon)
The AT-X 124 AF PRO DX lens is Tokina's first lens designed for use exclusively on Canon and Nikon Digital SLR cameras having an APS-C sized sensor.
This lens gives the Digital Photographer an ultra wide-angle zoom lens that has the equivalent of an 18-36mm zoom range on a 35mm film camera while maintaining a bright constant aperture of f/4. Specifcations: Focal range: 12-24mm Maximum aperture: F/4 Minimum aperture: F/22 Optical construction: 13 elements in 11 groups Coatings; Multi layer Angle of view: 99 degrees - 61 degrees Minimum focus distance: 11.8 ins Magnification ratio: 1:8 Zoom system: Rotary type zoom Aperture blades: 9 Filter size: 77mm Dimensions: 84mm diameter Dimensions: 89.5mm length Weight: 540g Lens hood included: BH-777 Star bayonet Features: Non-Rotating Filter Thread
Non-rotating 77mm filter threads mean special effect filters will not change when the lens' focus is changed. One Touch Focus Clutch
Fast internal focusing with Tokina's One-Touch focus clutch mechanism allows the lens to AF focus faster and switching between auto and manual focus is as easy as snapping the focus ring back and forth. Automatic Correcting of Aspherical Abberation
2 sharp-cut aspherical elements accurately correct aspherical aberration usually associated with ultra-wide angle lenses. Wide Aperture
Bright, constant f/4 aperture allows plenty of light to enter the camera for shooting in a wide variety of photographic situations. Materials Chosen for Ease of Use
Chrome plated brass mount plate and all-metal zoom unit can stand up to regular use while advanced polycarbonate outer lens barrels reduce the weight of the lens. Tokina Optical Technology Aspherical Optics
A standard lens is made up of a combination of spherical lens elements. Individual "lenses" within the lens are commonly referred to as "elements". A spherical element has an even curve to the surface of the glass. However, there can be problems with such elements; light entering the center of the lens and light entering at the edge may not be perfectly focused at the same point. This is called spherical aberration. More advanced computer assisted optical designs are creating lenses with more spherical elements. More spherical elements within a lens means a greater risk of spherical aberration having a negative impact on optical quality.
Wide-angle zoom lenses and wide-angle lenses with large apertures are especially at risk for spherical aberration.
To eliminate spherical aberration, Tokina employs aspherical all-glass elements in many of its optical designs to correct this problem. The aspherical shaped surface of the lens element focuses light rays entering both the center and edge of the element correctly at the film plane for an accurately focused image. In addition to correcting spherical aberration, these elements fully correct light quantity and distortion at the edge of the image and provide excellent results when used in combination with a floating element design.
Through a close collaboration with Hoya Corporation, the world's largest optical glass manufacturer, Tokina has succeeded in producing high quality precision molded all glass elements with a greater aspherical shape than any other lens manufacturer. This technique is unparalleled in its technological sophistication and precision. F&R Aspherical
This lens, the AT-X124 AF PRO DX encompasses Tokina's new F&R aspherical molded glass elements. These give outstanding performance with very even illumination in the corners and correction of spherical aberration across the image area. SD Super Low Dispersion
When standard optical glass is used in telephoto lenses, a phenomenon called chromatic aberration can occur. Chromatic aberration is the inherent tendency for glass to disperse (separate) a ray of light into the colors of the rainbow. The rainbow effect created by a glass prism is the most dramatic demonstration of chromatic aberration. In lenses, it is much less pronounced, but still creates slightly out of focus colors, akin to an "optical noise" that has a negative impact on the quality of the picture. To eliminate chromatic aberration, Tokina employs expensive, special glass material having super- low dispersion (SD) properties.
Lenses in the Tokina line-up with the SD mark incorporate these Super-Low Dispersion glass elements, minimizing the secondary spectrum or optical noise caused by chromatic aberration. HLD
Tokina's wide-angle and standard zoom lenses feature a higher quality of optical glass known as Tokina HLD (High-refraction, Low Dispersion) glass. Having higher refractive index and lower dispersion properties, HLD glass is far less likely than standard optical glass to create lateral chromatic aberration, which is often a problem with conventionally designed wide-angle lenses. Multi-Coating
Reflections off the surface of lens elements are the enemy to any photographer and to every lens manufa
