Tamron's various 28-300mm "ultra" zooms have been best sellers
since their first model of this type was introduced in 1999. Each subsequent
version featured improvements and this latest "4th generation" product
is the most desirable to date, since it includes a Vibration Compensation stabilizer
aside from a wealth of advanced optical technology. A digitally optimized, multi-platform
model, this compact and versatile zoom is suitable for many Nikon and Canon
35mm and digital SLRs with a sensor of any size. While traveling in the Caribbean
and during events in my hometown, I sometimes left my heavy pro system behind,
carrying only this single 10.7x zoom mounted on a Canon EOS 40D D-SLR.
VC Technology And Performance
While other companies also make lenses with a stabilizer mechanism, Tamron's
proprietary system is unique. The Vibration Compensation (VC) device features
three driving coils and slide balls around the compensator group of the lens'
optical system. A gyro detects shake and a 32-bit RISC CPU shifts optical elements
as required for the Anti-Shake effects. The incoming light rays are refracted
(bent) and the projected image is returned to the center of the frame, increasing
the odds of sharp photos.
An Anti-Shake system is a valuable amenity since it allows for shooting at longer
shutter speeds, reducing the need for a tripod or for a high ISO level. (Both
film and digital sensors provide superior image quality at lower ISOs.) A stabilizer
offers a secondary benefit useful in bright to moderately bright light. It allows
us to shoot at small apertures for extensive depth of field--and also the
best optical quality--without worrying about the longer shutter speeds
when hand holding the camera.
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The primary new feature of Tamron's 4th generation 28-300mm
zoom, the Vibration Compensation (VC) system is very effective.
While no stabilizer can work miracles, the VC mechanism allowed
me to make sharp photos at surprisingly long shutter speeds, particularly
when I was able to brace the camera, or my elbows, on some solid
object. (Image made at a 1/2 sec shutter speed at a 39mm focal length,
with elbows braced on a concrete railing, using an EOS 40D.)
All Photos © 2008, Peter K. Burian, All Rights Reserved |
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Construction And Design
Slightly larger and 5 oz heavier than the previous 28-300mm XR Di model, this
VC lens is still very portable. (Overall length has increased by only 0.7"
while the diameter has expanded by a mere 0.2".) When zoomed to the 300mm
end, the lightweight internal barrel extends by 3.3", but overall handling
is not affected to any obvious extent. It's solid, too, with a polycarbonate
barrel with pearl-black coating and a metal lens mount. The 1.3" wide
rubberized zoom ring and 1/2" wide focus ring are quite well "damped":
with enough friction for a familiar feel. Even so, zoom creep can occur when
the lens is pointed downward or upward, since the zoom lock switch can be set
only at the 28mm focal length.
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While this 28-300mm zoom is ideal for travel photography when you
want to carry only a single lens, its versatility makes the lens
a fine choice for other types of subject matter as well, including
events where the great range of focal lengths can be very useful.
(EOS 40D in Continuous AF mode; ISO 400; Hoya Pro 1 Digital Circular
Polarizer.) |
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Other switches include a selector for AF/MF and another for Vibration Compensation
On/Off. A ring with gold lettering adds a touch of class to this well-built
but affordable lens. Note, too, that the diaphragm mechanism contains extra
blades (for a total of nine) in order to enhance the blurred background effect;
out-of-focus highlights are closer to circular than hexagonal in shape.
Thanks to Internal Focusing (IF), the internal barrel does not rotate so the
effect of a polarizing filter remains constant. The IF mechanism also helps
minimize loss of light at the sensor or film plane and maximizes image brightness
at the corners of the photo. During autofocus operation, the focus ring does
rotate, creating a low-pitched hum that's barely noticeable in most circumstances.
A rotation of a mere 30° changes focus from 19.3" to infinity, for
quicker focus acquisition in AF or MF mode. A distance scale shows both feet
and meters but there's no depth of field scale, a typical omission with
variable aperture zooms.
Optimized for digital photography, this Di-series lens includes superior multilayered
coatings to minimize flare and ghosting that can be caused by a highly reflective
sensor. The optical formula is particularly impressive, including five distinct
types of glass: XR (high refraction index), GM (Glass-Molded aspherical lens)
elements, hybrid aspherical elements, LD (Low Dispersion), and AD (Anomalous
Dispersion). This diverse combination was intended to minimize the various types
of optical aberrations at short and long focal lengths and also in close focusing;
it also helps to control distortion.
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This digitally optimized zoom lens is remarkably well corrected
for flare caused by the highly reflective camera sensor and by external
light sources. The lens hood (included) is also quite effective.
Except in strong backlighting, that combination assured snappy contrast
without any evidence of flare. (Photo made with an EOS 40D using
a Hoya Pro 1 Digital Circular Polarizer that is also multilayer
coated.) |
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The minimum focusing distance is 19.3" at all focal lengths, providing
maximum magnification of 0.33x, higher than average for a lens of this type.
The actual working distance--from the front of the lens to the subject--is
a generous 12" when shooting at 300mm. While a true Macro lens is preferable
for tiny subjects, I was able to fill the frame with a couple of blossoms. I
was pleasantly surprised at the high image quality even at longer focal lengths--especially
in the f/11 to f/16 range that's useful for a suitable range of sharp
focus. Although the VC system minimizes the need for a tripod, no Image Stabilizer
can prevent blur caused by wind-induced motion; that still requires a high ISO
level for fast shutter speeds.
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A wide aperture Tamron lens such as the new 70-200mm f/2.8 model
is preferable for low-light action photography since it allows for
using faster shutter speeds at a lower ISO level. However, the latest
D-SLR cameras produce decent image quality even at ISO 1600; hence,
I found f/5.6 quite suitable for many shots during a horse jumping
competition. (Image made at the Royal Winter Fair, Toronto, at f/5.6,
at a 129mm focal length; EOS 40D.) |
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Performance Evaluation
During the test period, I made over 600 images with this lens and found that
all of the high-tech EOS 40D features--including Live View--functioned
perfectly. Autofocus was fast enough for just about any subject encountered
in travel photography, particularly in the 28-260mm range. By about 270mm, the
maximum aperture diminishes to f/6.3, reducing the amount of light that can
reach a camera's AF sensor. (This is typical with most of the "all-purpose"
zooms.) While autofocus continues to operate, it's obviously slower.
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While this lens was not designed for tracking erratic, high-speed
motion in sports photography, the AF system had no difficulty with
other types of subjects particularly at moderate focal lengths where
the wider maximum aperture allows plenty of light to reach the camera's
AF sensor. (At f/10 at 1/200 sec with a Canon EOS 40D in Continuous
AF mode; Hoya Pro 1 Digital Circular Polarizer.) |
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This "ultra zoom" was not intended for serious sports photography
enthusiasts, but autofocus was suitable for tracking the motion of more typical
subjects, such as marching bands. During a hockey game and equestrian events
in an arena, I used shorter focal lengths whenever practical. Pre-focusing on
a spot that a moving subject would reach also helped increase the number of
sharp photos in a subsequent series of action shots.
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During this amateur ice hockey game I was able to shoot from a position
close to the ice, so I generally worked at focal lengths around
50-100mm where the wide maximum aperture allowed plenty of light
to reach the camera's AF sensor. Consequently, autofocus performance
(using an EOS 40D) was quite suitable for action photography in
spite of the erratic motion of my subjects. (Photo made at 100mm
at ISO 800.) |
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