- 18-250mm focal length, only compatible with APS-C DSLRs.
- 27-375mm equivalent focal length on APS-C cameras, 28.8-400mm equivalent focal length on Canon APS-C cameras.
- Micromotor-type AF motor with full-time manual focusing.
- Image stabilization, Up to 4 stops cled.
- 62mm filters.
- Available in Canon EF, Nikon F (DX), Pentax KAF3, Sony Alpha, Sigma SA s.
- equipped with Super Multi-Layer Coating to reduce flare and ghosting.
- Hyper Sonic Motor (HSM) to ensure fast and quiet auto-focusing.
- The lens features a brass-made bayonet applied on the surface to reinforce strength for long-term use and enable high accuracy and solidity..
- For use with smaller chip APS-c cameras only.
Product Description
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18-250mm f3.5-6.3 DC MACRO OS HSM
From the Manufacturer
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High Performance, Compact, High Zoom Ratio Lens designed
exclusively for digital SLR cameras
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By revolutionizing the optical and structural design of the Sigma
18-250mm F3.5-6.3 DC OS HSM, this new lens achieves a compact
size and a minimum focusing distance of 13.8". New material,
Thermally Stable Composite (TSC) maintains its structure and has
little contractility especially in varying temperatures, is
incorporated into the lens barrel. It is convenient when you wish
to keep your equipment to a minimum and yet still be prepared for
all rtunities and situations, such as travels.
A wide range of photography is possible in one lens
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Covering wide angle 18mm to telephoto 250mm, this versatile lens
designed exclusively for digital SLR cameras, is suitable for
all-purpose photography including landscape, sport, and macro
photography. It is convenient when you wish to keep your
equipment to a minimum and yet still be prepared for all
rtunities and situations, such as travels.
Excellent for macro photography
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Close-up capability is improved with the minimum focusing
distance of 13.8" throughout the entire zoom range, and maximum
magnification ratio of 1:2.9. In APS-C size equivalent, macro
photography with approximately 1:2 magnification ratio is
possible. In addition, with this lens, the size and flaming of
subjects can be adjusted by rotating a zoom ring, making macro
photography easier than using fixed focal macro lens. For further
convenience, the maximum magnification ratio at each focusing
distance appears on the side of the lens barrel.
New design. Compact size.
Revolutionizing the design foundation results in compact size
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Optimization of the power arrangement by such things as
incorporating double-sided aspherical lenses, and reexamination
of design, the filter diameter size is reduced. This compact size
lens has the approximately 13x high zoom ratio with the filter
size of diameter 62mm, and dimensions of diameter 2.9" x Length
3.5". It ensures portability and overall ease of use, making it
perfect for travel and leisure photography.
New material TSC (Thermally Stable Composite)
---------------------------------------------
Thermally Stable Composite The new material "TSC (Thermally
Stable Composite)", which has little contractility especially in
temperature changes, as well as maintaining firmness, is
incorporated into the lens barrel. Compared to Polycarbonate
which is generally used, TSC has higher elasticity by
approximately 25%. Since thermal shrinkage is low, it has high
affinity to metal parts which contributes to high quality product
manufacturing. It also contributes to the parts such as the zoom
ring and scaling to be slimmer
Lens Construction
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In a conventional lens, focusing requires an extension of the
entire lens or the front lens group. However, to better
accommodate autofocusing mechanisms and closeup photography, a
need has arisen for lenses that do not change their length during
focusing or suffer from focus-dependent variation in aberration.
Therefore, Sigma has developed focusing systems that only move
elements within the lens barrel. These incorporate smaller and
lighter moving lens elements which help improve auto-focus speed.
With their unchanging barrel length and small variation in the
center of gravity, these lenses also enhance balance and
stability for the photographer. Furthermore, since the front of
the lens does not rotate, polarizing filters can be used with
extra convenience.
MTF Chart
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( https://images-na.ssl-images-.com/images/G/01/electronics/lenses/Sigma/18-250mm/SIGMA_18-250mm_img4_lg._V401503263_.jpg )
MTF (Modular Transfer Function) is one of the measurements that
evaluates a lens' performance, and it contrasts sensitivity at
different spacial frequencies. The horizontal axis is in
millimeters and shows the distance from the center of the image
toward the edges, and contrast value (highest value is 1) is
shown in the vertical axis.
The readings at 10 lines per millimeter measure the lens'
contrast ability (red lines), repeating fine parallel lines
spaced at 30 lines per millimeter measure the lens' sharpness
ability (green lines), when the aperture is wide open. Fine
repeating line sets are created parallel to a diagonal line
running from corner to corner of the frame, are called Sagittal
lines (S) and sets of repeating lines vertical to these lines are
drawn, called Meridional (M) line sets.
Distortion
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( https://images-na.ssl-images-.com/images/G/01/electronics/lenses/Sigma/18-250mm/SIGMA_18-250mm_img5_lg._V401503256_.gif )
effective distortion: When you take a picture of a lattice
pattern, it will appear as the blue dotted line shows. the red
line illustrates how the lattice pattern will appear in the
actual picture when any lens distortion is taken into account.
relative distortion: In this chart, the horizontal axis shows the
ideal image height (the distance from the center to the edge of
the image [mm]). The vertical axis shows the extent of
distortion. The extent of the distortion is represented by how
much Y, which is the actual image height, grows (or shrinks)
against Y0 which is the ideal image height.
Extent of distortion: D[%]=(Y-Y0/Y0)x100
When you take the picture of a square object, if the distortion
a show a minus value, the image will be seen as expanded
(Barrel distortion). If the distortion a is a plus value, it
will be seen as a recessed (pincushi on distortion). When the
distortion value is close to 0, the appearance of distortion is
very minimal.
Vignetting
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View Larger Image
( https://images-na.ssl-images-.com/images/G/01/electronics/lenses/Sigma/18-250mm/SIGMA_18-250mm_img6_lg._V401503259_.gif )
The horizontal axis shows the image height (the distance from
the center to the edge of the image [mm]). The vertical axis
shows the a of light in the image (based on the a of
light in the image center being 100%). If the peripheral a
of light is lower than the center, the four corners of the image
will be darker (vignetting).
Specifications
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Lens Construction 16 Elements in 13 Groups Angle of View (for
SD1) 76.5 - 6.5 degrees Number of Diaphragm Blades 7 Blades
(Rounded diaphragm) Minimum Aperture F22 Minimum Focusing
Distance 35cm / 13.8in. Maximum Magnification 1:2.9 Filter Size
Diameter 62mm Dimensions Diameter 73.5mm x Length 88.6mm / 2.9in.
x 3.5in. Weight 470g / 16.6oz.