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Tokina AF 19-35mm f/3.5-4.5 Zoom And New Kenko PRO Tele-Converters
By Peter K. Burian • August, 2000
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I appreciated the close focusing ability of the Tokina AF
19-35mm zoom in numerous situations. At most apertures,
at any focal length, image sharpness is outstanding in close
focusing. (Mormon Assembly Hall; at 28mm; handheld; f/8;
Fujichrome Velvia at EI 80.)
Photos © Peter K. Burian, 2000 |
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Although most lens manufacturers
offer fast (f/2.8) ultra-wide zoom lenses, these tend to be large, heavy,
and quite expensive. Tokina's own AF 20-35mm f/2.8 AT-X PRO is a superb
product but most photo enthusiasts do not require such a wide aperture
in a short zoom often used at f/16. If you fall into that category, the
new AF 19-35mm f/3.5-4.5 zoom would be well worth considering. It's compact
and lightweight, and offers performance beyond the norm for a mid-priced
zoom. In fact, its optics can meet professional standards as I discovered
while shooting 20 rolls on assignment in Salt Lake City and the Moab area
of Utah.
Physical Characteristics.
This is a lightweight lens but with a rugged feel and stainless steel
mount for long-term reliability. The rubberized zoom and focus rings are
adequately wide and knurled for good grip. The rotary zoom action is extremely
smooth and well damped; the manual focus mechanism is not as well damped
nor as smooth but works very well in practice. Less than a 45 degree rotation
is required for moving from infinity to the 1.3' setting for quick operation
in both manual and autofocus. AF operation was very quick indeed, and
fairly quiet, with the Nikon N80 used for my tests; I had no difficulty
tracking the motion of rapidly moving cyclists and dirt bikes at the famous
Slickrock Trail in Moab.
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I frequently used the AF 19-35mm zoom for close-ups of cyclists
and motorcycles at Slickrock Trail in Moab, Utah, at very
long exposures for a pan/blur effect. Autofocus performance
with a Nikon N80 was excellent. (At 35mm; SB28, fill flash;
1/8 sec exposure; B+W polarizer; Fujichrome Velvia at EI
80.) |
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There's a standard distance
scale (in meters and feet) and a focal length scale but no depth of field
markings--a common omission from zooms these days--so I used the camera
body's depth of field preview. For maximizing depth of field for landscapes
at Arches National Park, I referred to a Hyperfocal Chart, which lists
the ideal focus distance for every focal length and aperture. (This affordable,
laminated chart is available from Steve Traudt, Synergistic Visions, (970)
245-6700; www.synvis.com)
Design Features. The
new model offers some advantages over the AF 20-35mm f/3.5-4.5 zoom that
it replaces, in addition to lower price, plus some other noteworthy features:
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With the expanded spatial perspective of an ultra-wide lens,
plus extensive depth of field, images with high viewer appeal
are possible. The mid-priced Tokina AF 19-35mm zoom would
be a fine choice for any serious photographer first considering
a lens of this type. (At 19mm; f/16; Manfrotto tripod; hyperfocal
focusing; Fujichrome Provia 100F.) |
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The mechanical design is
similar but increased use of polycarbonate parts has reduced the weight;
this will be appreciated by outdoor, travel, and landscape photographers
especially when hiking or walking long distances. This is not the lightest
lens in its class because the THK designers insisted on internal components
with high durability.
The Internal Focusing mechanism
is also new. Unlike conventional designs, which often require movement
of the entire optical formula, such systems shift fewer components (less
weight). This strategy produces several benefits: increased AF speed,
improved sharpness at close range, and constant physical size (when focusing
or zooming). The front element does rotate but the filter mount on the
barrel does not. I really appreciated this fact when using a polarizer
or graduated filter while photographing the canyons in Dead Horse Point
State Park, near Moab.
The minimum focusing distance
has been shortened, important even in a wide angle lens for dramatic effects.
This zoom includes an element
of high refraction, low dispersion (HLD) glass to ensure superior image
quality. All elements are multi-coated to counter flare and assure faithful
color reproduction. They are made by Hoya, the world's largest optics
manufacturer; internal precautions against flare also ensure high contrast
images.
Focus does not shift when
zooming, so there is no need to re-focus after changing focal lengths.
I found this to be an advantage especially when working in manual focus.
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A tele-converter of top quality like the Kenko PRO 1.4x,
on a pro caliber lens, can produce excellent image quality.
Use professional shooting techniques as described in the
text for the most satisfying results. (AF-S Nikkor 80-200mm
f/2.8D ED IF; manual focus; Manfrotto tripod; B+W polarizer;
f/11; Provia 100F at EI 200.) |
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Performance Evaluation.
In addition to the stunning Utah landscapes, I used this lens frequently
for travel subjects on the grounds of the Mormon Temple, Salt Lake City's
premier site for tourists. While reviewing my slides under a 10x loupe,
I made the following notes:
Light falloff at the edges
of the frame is no longer apparent by f/5.6. Even at wider apertures,
this is noticeable only when the white temple and the sky fill the frame.
As with most ultra-wide zooms,
my conventional polarizer did produce vignetting (darkening of the corners
of the image) at focal lengths shorter than 22mm. A "thin ring" polarizer
would prevent this effect.
Because linear distortion
is well controlled at all but the shortest focal lengths, barreling (bowing
outward of lines near the edges of the frame) was minimal in the 24-35mm
range. Note: In architectural photography, it is important to avoid
tilting the camera to avoid apparent distortion of perspective. Position
the camera back parallel to the subject if you want straight lines to
be rendered plumb and true to the original.
Optical performance was superb
at the 19mm end at all but the widest aperture; corner sharpness matches
central sharpness at all apertures from f/11 to f/22, with quality usually
expected only in a single focal length lens. The resulting slides are
suitable for enlargement to 11x14 or for a crisp double page spread in
a magazine.
At other focal lengths, image
sharpness, clarity, and contrast are nearly as impressive, with the very
best results at 28mm. From f/5.6 to f/16, this lens produced slides suitable
for an excellent 8x12 enlargement, or a full page magazine reproduction,
at any focal length.
Because wide angle lenses
are often used at f/16, I was pleased to note that this aperture produced
slides with absolutely first-class quality at any focal length. This is
an important factor in landscape, close-up, and travel photography, and
whenever maximum depth of field is desirable.
High image quality is maintained
in extreme close focusing: the results are nearly identical to those listed
for greater focused distances.
Although a lens hood was
not provided, flare was a problem only in extreme backlighting; this was
a pleasant surprise and speaks highly of the effectiveness of the anti-reflective
strategies.
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The Tokina AF 19-35mm zoom proved to be highly useful in
people photography, when the surroundings were equally important.
Photojournalists frequently use lenses of this type to include
both the primary subject and its environment. (At 19mm;
f/11; original photo in color.) |
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Conclusion. Photojournalists
may prefer the Tokina ATX PRO AF 20-35mm f/2.8 model because of its very
wide maximum aperture, beneficial in low-light situations where flash
is not permitted. That PRO lens boasts even more rugged construction plus
two aspherical elements for outstanding performance even at the widest
apertures: in terms of edge to edge sharpness, even illumination across
the frame, and superior correction for aberrations and distortion.
If you routinely shoot at the
widest apertures, need to please critical commercial clients daily, or
enlarge your negs to poster size, by all means check out the PRO Tokina
zoom. Given my own shooting style--frequently stopped down--and choice
of subjects, I would be happy with the smaller AF 19-35mm f/3.5-4.5 model.
For my stock photography, for magazine covers, and for wall decor prints,
I could get by nicely with this more affordable alternative. Whether for
land or cityscapes, informal architectural photography or for environmental
portraits, I predict that this ultra-wide zoom will satisfy many discriminating
photo enthusiasts.
New Kenko Pro 1.4x And 2x
Tele-Converters
For my assignment in Utah, THK Photo Products Inc., also provided samples
of their new Kenko PRO tele-converters, labeled as the "Teleplus Pro 300"
series in Nikon AF-D mount. Since I did not take a long telephoto lens
on the Utah trip, I have not extensively tested these accessories. However,
I did use them with an 80-200mm f/2.8 zoom to shoot several rolls of slide
film.
Features And Compatibility.
The earlier Kenko tele-converters were already among the top rated independent
brand models. The new PRO series features a higher quality super-low dispersion
glass to correct chromatic aberrations and match the quality of the prime
lens. High quality multi-coated Hoya glass is used: five elements for
the 1.4x model and seven for the 2x model. Both have metal lens mounts
and a metal core so they are suitable for use with heavy telephoto lenses
and pro cameras. THK indicates that neither will cause any vignetting
on lenses of 100mm and longer.
They are recommended especially
for use with telephoto lenses of 200-500mm. These PRO tele-converters
can also be used with zooms, but are not recommended for those with a
range starting at under 50mm. Both are available in Nikon AF-D, Canon
EF, and Minolta AF mounts. Do note that autofocus is not maintained
with all lenses, including Nikon AF-S models and most zooms with small
maximum apertures. The THK web site (www.thkphoto.com)
provides specifics as to Nikon AF and Canon EOS compatibility issues.
In the fall of 2000, a new Teleplus PRO model, intended for Nikon AF-S/Silent
Wave lenses, should be introduced.
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Evaluation. I can offer
the following preliminary comments on these Kenko accessories:
- I used both PRO models
with the Nikon N80 body and the AF-S 80-200mm f/2.8D ED IF Silent Wave
zoom lens. Although THK indicates that these devices will not maintain
autofocus with the AF-S lenses, they did so occasionally, with very
good performance at those times. On conventional AF lenses, autofocus
performance should be highly reliable as with the earlier Kenko tele-converters.
- Optically, the PRO 1.4x
model was simply exceptional. If this level of quality is maintained
with long prime lenses, this tele-converter's reputation will exceed
that of previous Kenko models.
- As with all brands of tele-converters,
the PRO 1.4x model proved superior in maintaining high image quality--at
the widest apertures--than the 2x model. The PRO 2x device was most
impressive at a stop or two down from maximum aperture.
- Both devices are lightweight
but appear rugged. (The 1.4x model weighs 4.7 oz, and the 2x weighs
6.5 oz.) Aside from the issue of autofocus operation with AF-S/Silent
Wave lenses, they appeared to be fully compatible with the high tech
Nikon N80 camera; information exchange between camera and lens was maintained.
Note: Because all converters
reduce the light reaching the AF sensors, autofocus response--especially
in dim light--is not as quick. When the effective maximum aperture of
the lens/converter combination is smaller than f/5.6, most autofocus cameras
disengage AF operation. If autofocus does continue to operate, it is very
sluggish. This occurs with all brands of tele-converters making the 1.4x
models most suitable for f/4 or "faster" lenses and the 2x models for
f/2.8 or "faster" lenses if autofocus is important.
Conclusion. In order
to obtain information on compatibility with other lenses and cameras,
I interviewed professional wildlife photographer John Herbst (see www.grizzlyjhphoto.com).
He has used both Teleplus PRO models with an EOS Rebel 2000 as well as
a Nikon F5 and F100 with "fast" EF and AF mount lenses. "All of the equipment
functioned, confirming full compatibility," Herbst confirmed. "They're
sharp as a tack, too," he added. "I have been delighted with the results.
The new PRO models provide faster autofocus and are much sharper than
the older Kenko models."
With any long focal length--with
or without a tele-converter--professional shooting techniques are essential
for sharp images. Use the best lens available for the best results. Mount
the equipment on a rigid tripod, use reflex mirror lockup when practical
and a cable release to reduce the risk of blur caused by vibrations. As
Herbst has found, the Kenko Teleplus PRO 300 models should maintain pro
caliber sharpness with telephoto lenses of top quality. Though not inexpensive,
you can acquire these fine devices for much less than the cost of another,
longer lens; hence, they should be a suitable investment for value conscious
photographers.
For additional specifics on
Tokina, Hoya, and Kenko products, visit the THK web site at: www.thkphoto.com
For more information on photo opportunities in Utah, check the Utah Travel
Council web site at: www.utah.com.
Technical Specifications
Tokina AF 19-35mm f/3.5-4.5 Zoom
Maximum Aperture: f/3.5-4.5
Optical System: 13 elements in 11 groups; multi-layer coating
Angle Of View: 96 to 63°
Shooting Distance Range: 1.3' (0.4 m) to infinity
Focusing System: Internal
Filter Diameter: 77mm
Accessories: Optional BF-774 dedicated lens hood
Dimensions/Weight: 3x3.2" (80x82mm); 14.6 oz (390 g)
AF Mounts: Canon, Minolta, Nikon-D, Pentax
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