/ Tokina AT-X 280 AF PRO /
Glass
 The AT-X 280 AF PRO is constructed with high
quality optical glass multicoated lens elements created by Hoya Corporation, the world’s
largest manufacturer of optical glass. Two Aspherical lens elements and one SD (super low
dispersion) glass element are employed in the optical design to insure critical sharpness
across the film plane. One aspherical element is molded as one piece of optical glass created
with technology pioneered by Hoya. The other is a hybrid aspherical element.
Focusing
An internal focusing mechanism with a Tokina Focus
Clutch Mechanism gives this lens fast auto focus. The focus clutch feature, a signature of the
Tokina PRO series lenses, allows the manual focus ring to be snapped forward to an auto focus
position. This disengages the ring from the focus gearing and provides a faster, smoother auto
focus operation. When snapped back to the manual focus position, the ring is damped for a smooth
manual focus action not normally found in today’s auto focus lenses.
A refinement of the focus clutch mechanism has
been incorporated in the AT-X 280 AF PRO Nikon and Canon mount, so that now the lens’
focus ring can be snapped back to the manual focus position at any time. This improvement means
it is not necessary to change the AF/MF switch (on the body with Nikon or the lens with Canon)
every time the lens is changed from auto focus to manual focus mode.
Internal focus means the 77mm filter threads do
not move during focusing. The advantage is when a special effects filter is used it is not
necessary to readjust the position of the filter every time the focus is changed. A window has
been added to the AT-X 280 AF PRO that shows a distance scale. This makes it possible to tell
the focusing distance, regardless of the actual setting of the focus mode.
Like the rest of the lenses in the AT-X series,
the AT-X 280 AF PRO is what is commonly referred to as a parfocal lens. This means that if
focus is achieved at 80mm, then the lens is zoomed back to 28mm, the subject will still be in
focus.
To fit Canon EOS, Minolta AF, Pentax and Nikon-D
| Focal length |
28mm ~ 80mm |
| Maximum aperture: |
f/2.8 |
| Minimum aperture: |
f/22 |
| Optical construction: |
16 elements in 11 groups |
| SD glass: |
One element |
| Coatings: |
Multi-layer |
| Angle of view: |
75° 20’ to 30° 20’ |
Minimum focus
distance: |
1.6 ft. (0.5m) |
| Reproduction ratio: |
1:5.0 |
| Focusing system: |
Internal focusing |
| Zooming system: |
Rotary type |
| Number of diaphragm blades: |
9 |
| Filter size: |
77mm |
Maximum outer
diameter: |
3.3in. (84mm) |
| Overall length: |
4.5 in. (120mm) |
| Weight: |
28.6 oz. (810g) |
| Accessories, included |
Dedicated lens hood (BH-775),
fitted soft case |
© 2001 THK Photo Products,Inc.
www.thkphoto.com
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