The standard magnification lens for APS-C-formatted
camera as expected is proud to have a fast f/1.8 max aperture through the zoom
range and silent focusing with more important manual control. We have a
post-produced sample to test here and it will fit the Canon, Nikon and Sigma
cameras, with the recommended retail price of $1,199.
Processing and
features
Though this lens is proud of having f/1.8 max
aperture through zoom range, it still weighs 665g, not much as you may think.
Solid structured quality with high-quality plastic is used for the rest of the
lens. This lens feels comfortable on Canon EOS 60D which is used to test and
will be better balanced on cameras having slightly larger gripping. The lens is
covered with a glossy metal layer by parts and both the magnification and
focusing ring work smoothly, which strengthen the high-quality feeling of the
lens.
Sigma
18-35mm f/1.8 DC HSM A Lens
A still HSM focusing motor powers the
focusing kit, which confirms very fast and accurate focus, even on this
post-produced model. If your lens can display focusing errors, the new lens of
Sigma which supports USB Dock accessories, allows you to adjust focusing and updates
the software that’s applied with the lens, quickly and easily. Focusing and
magnification is performed internally, so the 67mm filter doesn’t rotate,
making the lens ideal for using with polarizing and graduated filters.
Manual focus is completely applied by
simply adjusting the focusing ring at any minute. Manual focusing worth your
satisfaction as the focusing ring is quite heavily braked, and works smoothly.
Closest focusing is 30cm from the sensor surface, excellent for shooting in
cramped environment, though the achieved max magnification rate of 1:5.2 can
make this lens less suitable for filling the frame of small objects.
The
67mm filter doesn’t rotate, making the lens ideal for using with polarizing and
graduated filters
Performance
At 18mm and max aperture, the sharpness at
the center of the frame is already excellent, clarity toward the image border
is quite excellent, which is quite impressive for a lens with f/1.8 max
aperture. Reducing the aperture a little bit will improve the sharpness, with
performance peak obtained between f/2 and f/2.8 for this focal length.
Zooming to 24mm creates a sharpness
reduction, though this lens is still sharp at this focal length. Sharpness at
max aperture is still prominent at the center of the image and the clarity at
the edge has lowered to the very good level. Lowering to f/4 creates max
performance for this focal length, with outstanding sharpness obtained all over
the frame.
Finally, at 35mm, there’s a slight drop in
overall sharpness, though the sharpness is still very good all over the frame
at max aperture. Max aperture throughout the frame is obtained between f/4 and
f/5.6 for this focal length.
Resolution
@ 18mm
Resolution
@ 24mm
Resolution
@ 35mm
Instruction
to read the diagram
The blue column represents the record from
the center of the image at many apertures and the green one is from the edge.
The average of them results in the red column.
The meter on the right is the indicator for
real-time image res. The higher the column is, the better the performance is,
just that simple.
For this review, the lens is tested on a Canon
EOS 600D using Imatest
Chromatic aberration is extremely
well-controlled for a magnification lens having such good max aperture. The
clearest edge can be seen with the frame border at max aperture of 24mm, though
the CA level is low enough to create just a few problems here.
@
18mm Chromatic aberration
@
24mm chromatic aberration
@
35mm chromatic aberration
Instruction
for reading the diagram
Chromatic aberration is the powerlessness
of the lens when concurrently focusing on the sensor or all colored-film of the
visible light. Severe chromatic aberration creates border or halo around the
sharp edge in the image. It can be omitted by software.
Apochromatic lens has special lens
component, no spherical, low dispersion… to minimize the problem, so they’re
more expensive.
Illumination reduction at the frame corner
is not as strong as you predict for a lens with f/1.8 fast aperture all over
zoom range. At 18mm and f/1.8 the corner is only 1.25 point darker than the
center of the image and at 35mm, the corner is only 1.5 darker. Visual unified
illumination is obtained with aperture lowering down to f/4 or more all over
zoom range.
Distortion at both ends of the lens is
pretty clear, but not too strong with 2.71% body distortion at 18mm and 1.06% pincushion
distortion at 35mm. the distortion sample is unified all over the frame, so it
will be easy to edit in the image editing software later.
A petal-shaped lid is provided with this
lens, the thing that work properly when blocking the lens from unnecessary
light which may cause contrast loss or blue. Even when shooting against the
light, contrast is still good.
Samples
Wide
angle | 1/80 sec | f/6.3 | 18.0 mm | ISO 100
`
Telephoto
| 1/80 sec | f/6.3 | 35.0 mm | ISO 100
Closest
focus is 30cm | 1/200 sec | f/2.5 | 23.0 mm | ISO 100
Quite
compelling focus blur| 1/200 sec | f/1.8 | 31.0 mm | ISO 100
1/1000
sec | f/1.8 | 18.0 mm | ISO 100
1/60
sec | f/2.8 | 35.0 mm | ISO 200
1/100
sec | f/6.3 | 18.0 mm | ISO 100
1/125
sec | f/9.0 | 18.0 mm | ISO 100
Price
With the uniqueness at releasing time,
having f/1.8 max aperture throughout the zoom range, it’s hard to create
face-to-face comparison. However, when the recommended retail price of $1,199 is
compared to the current price of f/2.8 lens of Canon and Nikon in the same
range, it’s ranked pretty good, especially when this lens is almost $300 cheaper
than Nikon 17-55mm f/2.8 and only $105 more expensive
than the Canon 17-55mm f/2.8 IS lens. Adding to the cost of the prime lens
mentioned in this line will be much more expensive than on any other system.
Conclusion
In the past, Sigma created a niche market so
that they could create interesting and new optics that didn’t exist in the
product line of any makers, like 15-30mm & 12-24mm lenses
for full-frame camera, which was the first of a kind.
This lens opens a new opportunity for the
owners of APS-C-formatted camera for lowlight shooting and using creatively the
image depth field with a max aperture of f/1.8, normally for lenses with fixed
focal length. Provided image quality, especially at shorter focal length
belongs to the regular level for fixed-focal length lenses.
Advantages
·
Excellent sharpness
·
Unchanged f/1.8 aperture
·
Less light reduction for a f/1.8 lens
·
Good structure
·
Reasonable price
Disadvantages
·
No actual problem
Rating
·
Features 4.5/5
·
Processing 4.5/5
·
Performance 5/5
·
Price 4.5/5
·
Overall review 4.5/5
Technical specs
|
Overall
·
Lens support: Nikon AF; Canon EF-S; Sigma SA
Lens
·
Focal length: 18mm - 35mm
·
Viewing angle: 44.2° - 76.5°
·
Max aperture: f/1.8
·
Min aperture: f/16
·
Filter size: 72mm
·
Equivalent: 27mm - 52.5mm
·
Internal focus: yes
Focus
·
Min focus: 28cm
·
Stabilization: no
Structure
·
Blades: 9
·
Components: 17
·
Group: 12
Container
·
Container: front and back lids, lens cap,
sleeve
Size
·
Weight: 810g
·
Height: 121mm
|
