The Tokina 28-70 is an auto focus lens that is more commonly known as the AT-X 287 PROSV. Because this lens features a Focus Clutch Mechanism, users are able to choose whether they would like to manually focus the lens or use the auto focus feature.
Optics
The Tokina lens features a focal length of 28mm to 70mm, a minimum aperature of 2.8 and a maximum aperature of 22. This lens was constructed from 16 different elements that have been assembled in 12 groups. Each part of this lens is finished with many layers of coatings to make it as durable as possible.
Zoom
The Tokina AT-X 287 PROSV 28-70 lens can focus on a subject as close as 27 inches away. This lens utilizes an Internal Focusing System when it is set on auto focus but it also has a rotary zooming system to help the user achieve the photo they want. The 27-80 lens features 8 diaphragm blades and has a filter size of 77mm.
Internal Focus System
The Internal Focus System used in the Tokina 28-70 allows for the elements of the lens to move for zooming without changing the actual length of the lens itself, making it ideal for telephoto designs. Advantages of this focus system are the ability to focus faster, improved handling because the center of gravity does not change, compact lens design and improved use of filters with the lens because the actual threads don't rotate.
Focus Clutch Mechanism
Switching from auto focus to manual focus is easy with the Focus Clutch Mechanism featured in the Tokina 28-70 lens. This mechanism uses a ring to determine which setting is being used. Rotate the ring on the lens to switch from one setting to the other.
Dimensions
The Tokina 28-70 optical lens was designed to be lightweight. This lens features an outer diameter of 3.3 inches and a length of 4.3 inches. The lens weights just 25.2 ounces.
Mounting
The Tokina 28-70 optical lens can be mounted on a number of cameras, including the Pentax AF, Nikon-D, Minolta AF and Canon EOS. When you purchase this lens, it comes with a lens hood cap and a soft carrying case for protection. The 28-70 lens can also be used with a variety of filters to achieve desired effects.
Tags: Tokina 28-70, auto focus, lens features, 28-70 lens, Clutch Mechanism