School - Dictionary - AS (Tokina)

 
The abbreviations means
AS = Aspherical Optics
 
 
Explanation from Tokina
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.
 
 
See examples of effected products
Tokina AT-X 16-28mm f/2,8 PRO FX
Tokina AT-X Pro 16-50mm f/2,8 DX
 
See links
tokinalens.com




Top list
Our four most popular lenses (see all)
Tamron AF SP 70-300mm f/4-5,6 Di VC USD Tamron AF SP 70-300mm f/4-5,6 Di VC USD
Canon EF-S 55-250mm f/4-5,6 IS II Canon EF-S 55-250mm f/4-5,6 IS II
Tamron AF 18-270mm f/3,5-6,3 Di II VC PZD Tamron AF 18-270mm f/3,5-6,3 Di II VC PZD
Nikon AF-S DX 35mm f/1,8 G Nikon AF-S DX 35mm f/1,8 G
Follow us on Facebook
Through our Faceboook group you will recieve news regarding everything that concerns camera lenses and Lensora.

Lenses for Canon
Here are a few popular alternatives (see all)
Tamron AF SP 70-300mm f/4-5,6 Di VC USD Tamron AF SP 70-300mm f/4-5,6 Di VC USD
Canon EF TS-E 24mm f/3,5 L II Canon EF TS-E 24mm f/3,5 L II
Tokina AT-X Pro 16-50mm f/2,8 DX Tokina AT-X Pro 16-50mm f/2,8 DX
Tamron SP AF 17-50mm f/2,8 XR Di-II LD IF VC Tamron SP AF 17-50mm f/2,8 XR Di-II LD IF VC
School
Our articles will educate you (see all)
Protect your lens with a filter
Buy a new or a used lens?
See pictures taken with a certain aperture value
A lens is born

Lenses for Nikon
Here are a few popular alternatives (see all)
Sigma 18-200mm f/3,5-6,3 DC OS HSM Sigma 18-200mm f/3,5-6,3 DC OS HSM
Nikon AF-S DX 35mm f/1,8 G Nikon AF-S DX 35mm f/1,8 G
Nikon AF-S 500mm f/4 D IF-ED II Nikon AF-S 500mm f/4 D IF-ED II
Tokina AT-X DX 10-17mm f/3,5-4,5 Fisheye Tokina AT-X DX 10-17mm f/3,5-4,5 Fisheye
See lenses for your camera
Below you will find some models (see all)
Nikon D40x
Canon EOS 2000D
Nikon D1
Nikon D4

Newly added lenses
Nikon AF-S 400mm f/2,8 E FL ED VR

Nikon AF-S 400mm f/2,8 E FL ED VR
Nikon AF-S DX 18-55mm f/3,5-5,6 G VR II

Nikon AF-S DX 18-55mm f/3,5-5,6 G VR II
Nikon AF-S 50mm f/1,8 G SE (Special Edition)

Nikon AF-S 50mm f/1,8 G SE (Special Edition)

Three popular lenses to look at
Canon EF 70-300mm f/4-5,6 IS USM

Canon EF 70-300mm f/4-5,6 IS USM
Nikon PC-E 45mm f/2,8 D Micro ED

Nikon PC-E 45mm f/2,8 D Micro ED
Nikon AF 50mm f/1,4 D

Nikon AF 50mm f/1,4 D

Recently visited lenses
Canon EF 14mm f/2,8 L II USM

Canon EF 14mm f/2,8 L II USM
Nikon AF-S DX 10-24mm f/3,5-4,5 G IF-ED

Nikon AF-S DX 10-24mm f/3,5-4,5 G IF-ED
Tamron SP AF 17-50mm f/2,8 XR Di-II LD Asph IF

Tamron SP AF 17-50mm f/2,8 XR Di-II LD Asph IF

Recently visited cameras
Canon EOS 650D

Canon EOS 650D
Canon EOS 750D

Canon EOS 750D
Canon EOS 1100D

Canon EOS 1100D
Nikon D40

Nikon D40