|
After a
six-year absence from the high-speed pro
macro market, Tokina jumps back in with
this 100mm f/2.8 AT-X. Unlike its predecessor,
the 90mm f/2.5 AT-X, the newcomer
is a true macro lens (focusing
to 1:1)-a clear improvement
over the defunct 90mm that
focused only to half-lifesize.
Like the 90mm, however, the
new 100mm f/2.8 handles bellows
extension in a different way
than (almost) any other macro
lens. Bellows extension, a phenomenon
common in large-format
photography, refers to the light
falloff that occurs when the lens
aperture moves away from the
image plane during focusing.
With most S LR lenses, the movement
is negligible, but with 1:1
macro lenses, which by design
require relatively long travel to go
from infinity to maximum magnification,
the bellows factor ( i.e., the
amount you must adjust exposure
to comoensate for the diminished
light transmission) can be considerable.
W ith this Tokina, for example,
the image plane receives
two stops less light at close focus
than at infinity. When using most 1:1
macro lenses on today's AE SLRs; as you
focus from infinity to 1:1, the AE system's
aoerture readout remains constant as
shutter speed lengthens to compensate
for the light loss. This Tokina is the same,
except for this: the aperture readout also
changes as focus moves closer, going
lroml /2.8 to f/5.6.l t's an indicationo f the
effective aperture, not the actual aperture.
Don't be alarmed. At maximum aperture,
you're still getting the depth-of-field of an
f/2.8, even though your camera's LCD
says f/5.6.
HANDS ON
Another unusual trait: the
focus-rangel imitations ystem. Most close
up lenses with focus limiters offer full- and
non-macro ranges, but this Tokina has a
single two-way switch that provides three
options. lf you focus outside the macro
range (i.e.,1 : 2 to infinity), and switch from
Full to Limit, the focusing system permits
only non-close-up subject distances (which
is great for portraitists). Conversely, if the
lens is focused between 1:1 and 1:2, andyou switch from Full to Limit, it focuses only
within the close-up range (a boon to insect
and jewelry photographers, among others).
The third option is, of course, the full-focusing
range. Sigma's 105mm f/2.8 DG
Macro operates similarly.
Physically, the Tokina 100mm f/2.8 is
average in size and weight for its class, and
has a large, knurled focusing ring (rubberized);
matte-black crinkle finish; and ampsized
focus, depth-of-field, and magnification-
ratio scales.( Meters are in yellow; feet
in white; magnification ratios in blue.) The
manual-focus action is long (as
with most true macros). and
extremely well-damped.
IN THE LAB
SQF data indicates
excellent performance at all tested
apertures and magnifications. The
distortion perormance is among
the best we've ever seen-minimal
pincushioning (0 .340%) according
to DxO Analyzer tests. Light falloff
was undetectable by f/4, about
average for this lens class. At the
close-focus distance of 11.8 inches
(1:1), center sharpness was
excellent from f/2.8-22 and very
good at f/32. Corner sharpness
was excellent across the entire
aperture range, with best performance
at f/l 1. These are among
the best lab results we've produced
from a 100mm/105mm f/ 2.8.
CONCLUSION
Covering the full
35mm frame, this pro-grade macro
is optimlzed for DSLRs thanks to
improved multi-coatings that suppress
reflections off digital sensors.
With its superb distortion and sharpness performance, three focusing ranges,
and 1:1 maximum magnification, this lens
is a superior short-tele professional macro
lens. And pricing? Tokina and Sigma's pro
macros are each about $399 (street), and
Tamron's is $450 with rebate. Nikon and
Canon, meanwhile, get between $500
and $650 street for their comparable
glass. The new Tokina forces the question:
Are the others worth it? Tough call!
SPECIFICATIONS
100mm (97.02mm tested), f/2.8 (f/2.91 tested), 9 elements in 8 groups. Focusing turns 120 degrees clockwise.
• Diagonal view angle: 24 degrees.
• Weight: 1.11 lb. n Filter size: 55mm.
• Mounts: Canon AF, Nikon AF.
• Included: Lenshood. n Street price:
Approx. $399.
What's Hot
• Great optical performance for low price.
• 3 focusing ranges (full, 1:1-1:2, and1:2-infinity).
• Easy switching from manual to autofocus.
What's Not
• Available in Canon and Nikon mounts only.
|
