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New Tokina AT-X 28-80mm f/2.8SD AF PRO
By Peter K. Burian November, 2000
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Even on extremely bright sunny days, flare was rarely a
problem, thanks to the corner cut lens hood and internal
flare-cutting precautions. This factor is important since
many zoom lenses are prone to contrast reducing flare. (At
35mm; f/11; B+W polarizer; Elite Chrome 100.)
Photos © Peter K. Burian, 2000 |
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Dedicated to sophisticated
design and engineering, Tokina makes lenses with an excellent reputation;
the best of these bear the AT-X designation, denoting "Advanced Technology-Xtra."
These models--bearing a gold stripe indicating premium grade optics--include
the most advanced technology, superior mechanisms, and lens coatings.
The newly redesigned AT-X 280AF PRO is a fine example. Retaining the best
features of its 28-70mm f/2.6-2.8 predecessor, the 28-80mm f/2.8 model
offers several added benefits: an extra 10mm, internal focusing, a constant
maximum aperture, an upgraded optical formula, and a refined AF/MF switching
mechanism.
The previous 28-70mm model
included an element of low dispersion glass, but the addition of two aspherical
elements helps assure even better image quality at the short focal lengths
of the new model. Such elements--with a non-spherical surface--cause all
light rays to converge at a common point. This design feature offers several
benefits: correcting linear distortion and spherical aberration (curvature
of field) for more consistent edge to edge sharpness even at wide apertures,
reducing halo and comatic flare, and minimizing size/weight as fewer elements
are required to achieve high optical quality.
Several mechanical features
have also been improved. The "focus clutch" mechanism--used to shift between
manual and autofocus--now operates at any focused distance, so the shift
can be made instantly. A new distance scale under glass allows the photographer
to determine focused distance not only in manual focus, but also in autofocus
operation. Finally, the "feel" of the manual focus ring has been improved,
with greater friction to satisfy the most demanding traditionalist.
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Because this Tokina zoom is a professional tool, I used
it with confidence while shooting on assignment. The technical
quality of the images proved to be exceptionally high, easily
competitive with that of many single focal length lenses.
(At 28mm; f/11; B+W polarizer; Ektachrome 100VS.)
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During the summer, I used this
zoom lens often for a variety of subjects including the colorful craft
at a drag boat race, pleasure boats and its occupants on a lake, architecture,
portraits of people at several festivals, the action at a hot air balloon
race, and flower gardens. In all cases, the lens performed in an exemplary
manner as detailed in a later section.
Design Characteristics.
Even on first examination, this zoom certainly appears to be a professional
tool. It's built of aluminum alloy instead of "space-age plastics" to
withstand pro level abuse. This does increase weight but also increases
the pride of ownership. The lens bayonets onto the body with an authoritative
click, assuring a tight fit. As befits the PRO designation, long-term
reliability seems probable. The external matte, crinkled finish is hardened
Alumite for increased durability and a top quality appearance. Other features
are worth noting as well:
The matching "corner cut
lens hood" is designed to shade the front element at all focal lengths
and it's well flocked to minimize flare. The hood for the earlier 28-70mm
zoom screwed into that lens' filter thread so it was a bit slow to mount
and remove. That problem has been solved. The hood for the AT-X 28-80mm
f/2.8 AF PRO attaches to the external part of the barrel, with a mere
45° twist. When not in use, it can be mounted in a reversed manner, another
advantage of the new design.
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When any lens is tilted upward, linear distortion ("keystoning")
occurs. This is not an optical flaw in the lens. In fact,
the PRO Tokina zoom is very well corrected for linear distortion.
(At 28mm; f/11; B+W polarizer; Elite Chrome 100.)
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Multilayer coating is applied
to all elements (made by Hoya Corp.) for maximum light transmission, excellent
contrast, and reduced reflections or ghost images of the diaphragm in
strong backlighting.
Focus and zoom operation
is "internal" so the front element does not rotate. This made using a
polarizer most convenient because the effect did not change when focusing
or zooming. As well, the overall length of the barrel does not change,
so optimum balance is maintained.
This is a rotary (not push/pull)
type zoom with a stiff, incredibly smooth operation indicating precise
machining tolerances. This stiffness assures that focal lengths do not
shift accidentally.
Noticeably larger/heavier
than its 28-70mm predecessor, the AT-X 28-80mm f/2.8 AF PRO is well-balanced,
and ideal for use with a hefty pro SLR camera. Tokina offers some compact/
lightweight zooms, too, but for its professional line, no compromises
were made purely for the sake of convenience.
The manual focusing mechanism
is so well damped that most photographers making the switch from an older
conventional lens will notice little difference in operation.
The distance scale (in feet
and meters) is highly legible, as are the markings for focal lengths.
Infrared focusing index marks are provided for the 80mm, 50mm, and 28mm
focal lengths.
As with most rotary zoom
autofocus lenses, no depth of field marks are provided; use the camera's
depth of field preview control or refer to the charts provided in the
instruction sheets.
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This Tokina AT-X PRO lens is capable of producing images
of high contrast, with extreme sharpness and excellent resolution
of intricate detail across the frame. Color rendition is
accurate and linear distortion is very well controlled.
(At 80mm; f/8; B+W polarizer; Elite Chrome 100EC.)
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Autofocus Evaluation. The
focus clutch mechanism is still rare on most lenses but its method of
operation is worth noting. For autofocus (AF) push the focusing ring forward
until it reaches the line marked "AF." On the older 28-70mm zoom, the
focusing distance scale was covered by the ring, but this does not occur
with the new lens. As with most recent AT-X lenses, the ring does not
rotate during AF operation. Because there is less load on the focus motor,
autofocus is smoother, faster, and quieter. Though not silent, operation
is fairly quiet with a high-pitched sound.
With this latest AT-X lens,
there is no need to set the focus for infinity before shifting between
manual and autofocus. For manual focus, pull the ring back (toward the
camera) anytime, until it snaps into place at the line marked "MF." In
the Nikon and Canon AF mount versions, the lens can be set for manual
focusing without setting the AF/MF control on the camera body to MF, increasing
overall speed of operation. (With Minolta and Pentax cameras, the AF/MF
switch on the camera body must also be flipped to change focus mode.)
Contrary to some comments on Internet photography web sites, focus cannot
be touched up manually when the lens is set for AF.
With an EOS-1N, autofocus response
was extremely reliable with portrait and landscape subjects. Focus was
instantly achieved on the desired area, such as a person's eyes. Even
in low light around sunrise and sunset at the lake, reliable AF operation
was maintained; this was understandable, as the wide maximum aperture
of this PRO lens transmits plenty of light to the AF sensors. Continuous
tracking focus performance with soldiers marching at a fast pace was highly
acceptable, surprisingly good for a lens with a conventional autofocus
motor. However this may be academic because a zoom of this focal length
range is unlikely to be used for action photography such as motor racing
or sports.
Optical Evaluation. As
expected with pro lenses, the Tokina AT-X 28-80mm f/2.8 AF PRO produced
excellent image quality at all focal lengths, focused distances and apertures.
The super-low dispersion element countered aberrations at the longer focal
lengths, while the two aspherical elements assured superior image quality
across the entire frame at shorter lengths. The AT-X 28-70mm f/2.6-2.8
AF PRO zoom received a five-star ("Super") rating from Germany's highly
respected foto magazine and this AT-X 28-80mm f/2.8 AF PRO lens is a superior
lens. Flare is very well controlled with internal measures. Clarity, resolution,
sharpness, and definition of fine detail range from excellent to superlative.
Under a 10x loupe, all of my slides are razor sharp. Even at the widest
aperture, center sharpness is extremely high. By f/4 edge sharpness is
excellent. From f/5.6 to f/11, edge sharpness matches central sharpness
at all focal lengths, an impressive achievement. Even in extreme close
focusing, resolution is very high.
This wide to short tele-zoom
is capable of producing image quality adequate for a fine 16x20 print,
or a double-page spread in a magazine, at all but the widest aperture
at all focal lengths. At f/2.8, you should still be pleased with 11x14
prints. Aside from sharpness, contrast is high, important especially in
flat, cloudy-day lighting for snappy images. As with any zoom, the hood
is least effective at longer focal lengths so change your shooting position
slightly if flare is apparent on the viewing screen. For the absolute
sharpest images at any focal length, stop down to f/11 and the results
will satisfy even the most critical photo buyer.
Conclusion. While the
moderately priced Tokina lenses--like the AF 28-105mm f/3.5-4.5 zoom--tend
to be the hot sellers in this brand, serious photo enthusiasts should
definitely check out the professional caliber AT-X 28-80mm f/2.8 AF PRO.
Its superb performance, rugged construction, and wide maximum aperture
definitely warrant the extra cost for those who demand the finest quality
and want a "fast" problem-solving lens as well. As the only 28-80mm f/2.8
AF zoom (at the time of this writing) it's more versatile than the 28-70mm
models, with the extra 10mm making it useful as a portrait lens.
In comparison to some of the
camera makers' pro zooms, this AT-X PRO lens will seem surprisingly affordable.
Can you still get a lens of rugged construction and fine imaging capabilities?
I cannot vouch for every Tokina lens, but the answer is a definite "yes"
for the AT-X 28-80mm f/2.8 AF PRO model. It merits a place in the "best
value" category of lenses likely to satisfy the discriminating photo enthusiast
and the working professional. If you're looking for a "fast" zoom for
serious photography, this model is worthy of your consideration. For more
information contact THK Photo Products, 2360 Mira Mar Ave., Long Beach,
CA 90815; (562) 494-9575 fax: (562) 494-3375. www.thk.com.
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Technical Specifications
Lens Construction: 16 elements in 11 groups; one low dispersion
and two aspherical elements
Angle Of View: 75 to 30°
Maximum/Minimum Aperture: f/2.8 and f/22
Minimum Focusing Distance: 1.6' (0.5m)
Filter Size: 77mm
Dimensions: 3.3x4.5" (84x120mm)
Weight: 28.6 oz (810 g)
Accessories: Hood and soft case included
AF Mounts: Canon, Minolta, Nikon D, Pentax |
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