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Tamron 28 to 300mm Lens How Compact Can You Get
By George Schaub November, 2002
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One
of the real fun things you can do with a long tele lens
is compress space, an effect known as “stacking.”
Here’s a photo of a marketplace in Seoul made
with the 28mm setting (A, above), then with the lens
racked out to the full 300mm (B, below). Note how the
signs turn into a visual collage, an effect of the focal
length crop. Also note how sharply the lettering reads.
Photos
© 2002, George Schaub, All Rights Reserved
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If you go way back you remember
the first telephoto zoom lenses as heavy, ungainly things that were
often more trouble than they were worth. Travel a bit ahead in time
and check out the wide-to-tele zooms, and you get the same thing, with
all sorts of problems that were not quite solved at numerous focal length
settings. In the here and now all that has changed, especially when
you consider the latest XR series lens from Tamron—the 28-300mm
f/3.5-6.3. When we spell out the specs you might not believe them. The
lens is 3.3” in length and weighs 13.5 oz and has a filter diameter
of 62mm. The minimum focusing distance is 19.29, throughout the entire
focal length range.
Gotten off the floor yet? Here’s a lens that covers just about
every focal length setting except super wide that might just be the
be-all and end-all for travel photographers. Indeed, Tamron claims that
this is the world’s lightest, most compact 28-300mm yet, and who
are we to doubt them? All we can do is be impressed with what they’ve
accomplished with this lens. We couldn’t wait to get in the field
to see if all this impressive technology can take a good picture as
well. Indeed, when we first opened the box we were sure it was the wrong
lens and the box itself was mislabeled. But lo and behold it was the
one!
But before we venture forth, we thought we’d take a few moments
to run you through the alphabet soup technology that makes this lens
what it is, including XR, ASL, LD, AD, ADAH, ZL, BBAR, and IF. Confused
yet? Well, for those who might want to delve into these mysterious acronyms
and abbreviations, see the accompanying sidebar below.
Another tidbit of advanced tech shown in this lens is what Tamron dubs
a “Super Hybrid Mount.” The bayonet mount on the lens uses
hybrid materials made of stainless steel and what they call “engineering
plastic.” The benefit is a reduction in weight and strength that
they claim is equal to that of metallic (brass) material normally used
for the mount. This heavy-duty mount is designed to extend the flange
portion of the mount, an important connecting point between camera and
lens. On the weight side, the mount is 70 percent lighter when compared
to the previous Tamron 28-300mm zoom.
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In The Field
All this tech stuff is most impressive, but the picture tells the tale.
As mentioned, the lens is about as long and heavy as a modern 35-105mm.
I used it on a Canon EOS-1N and every mode worked great and autofocusing
was silent and efficient. For the most part I worked in AV mode, and
shot with Agfa’s new ISO 400 Optima color print film. This gave
me a good hand holdable shutter speed in most instances, especially
since I try to get it at f/8 for most images. At the wider settings
the lens is crisp and clear with no noticeable falloff at all. At the
tele settings, particularly 300mm, edge sharpness was also very good,
although keeping the shutter speed at or over 1/250 sec is always recommended
for this focal length.
In all, the Tamron 28-300mm lens is perhaps the perfect traveling companion.
It handles just about every location and point of view, and does so
with a quality that is pleasing to the eye. It’s almost hard to
believe that a zoom of this magnitude and range can deliver the goods,
but this Tamron will now be a constant companion on my travels. All
I need to do is add a fast 24mm for available light, and I’m all
set for the road.
For more information, contact Tamron at www.tamron.com.
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Even
when you’re not using the lens throughout its range
it delivers sharp and clear images at more “normal”
settings, here at 75mm.
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The Alphabet Soup Of Tamron
Lens Technology
XR: The namesake of
the lens line stands for Extra Refractive Index, which is a numerical
expression that compares the speed of light in a transparent medium, such
as glass, with the speed of light in the air. The higher the number the
thinner a given element. Extra Refractive Index glass is said to bend
light more effectively than normal or lower refractive index glass and
can compensate for specific aberrations within an optical design.
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Benefits: Shortens length of
the entire optical system; shorter distance from the diaphragm to the
front surface of the objective lens; lessens diameter of the front element;
smaller overall lens diameter; smaller lens and minimal aberration.
ASL: This stands for
aspherical elements, and Tamron has developed a process that has allowed
for the mass production of aspherics they call Hybrid Aspherical.
Benefits: One aspheric can replace two regular elements without sacrificing
optical performance; improvement of corner-to-corner sharpness; reduction
of distortion at wide angle focal lengths; and provides even illumination
while it reduces flare.
LD & AD: Low Dispersion
(LD) elements are made from special glass with extremely low dispersion
indices that separate or refract a ray of light into rainbow colors. Chromatic
aberration is a form of optical noise that reduces sharpness and can plague
telephoto and zoom telephoto lenses. AD (Anomalous Dispersion) glass is
a special optical glass that delivers an abnormally large partial dispersion
ratio, the amount of dispersion at a given wavelength range within visible
light.
Benefits: The LD and AD elements are said to effectively compensate for
chromatic aberration and improve contrast and sharpness. Solves both chromatic
aberrations in telephoto lenses and lateral chromatic aberrations associated
with wide angle lenses.
ADAH: This stands for
“Anomalous Dispersion-Hybrid Aspherical,” the manufacturing
method of adhering a specially treated aspherical layer to the finished
AD glass element.
Benefits: Perfect bonding of the two elements while maintaining compact
size and lightweight.
ZL: The Zoom Lock can
be activated when the lens is at the 28mm focal length setting.
Benefits: Prevents the dreaded “zoom creep”; the lens will
not slip out to the longer settings when you are carrying it around.
BBAR: A thin dielectric
or metallic film applied to the lens.
Benefits: Reduces reflections and increases the effective transmission
of the element.
IF: Internal Focusing
enables focusing of the lens without changing its length. All internal
optical movement is limited to the interior of the non-extending lens
barrel.
Benefits: Compact, lightweight construction; closer focusing distances.
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