Product Description
Lightweight, Compact Fast Standard Zoom Lens is Designed
Exclusively for Digital SLR Cameras, with 17mm Wide Angle Coverage
Exclusive design for digital SLR cameras achieves a fast standard zoom lens that
covers virtually the same angles as focal lengths of 26-78mm when converted to a
35mm format. The wide-angle focal length is established at 17mm (26mm
equivalent) to obtain a wider angle of view than ordinary standard zoom lenses,
while maintaining the remarkably lightweight and compact size of the earlier
full frame zoom lens model. Since the lens is designed exclusively for APS-C
sized digital cameras, the image circle diameter has been reduced. Moreover,
careful adjustments to the design have achieved a lightweight, compact body with
a filter diameter of 67mm, overall length of 81.7mm (3.2) and weight of 434g
(15.3oz.).
Optical System Uses Special Glass, and Is Optimized for Digital SLR
Characteristics to Enhance Optical Quality in a Compact Design
The use of XR (Extra Refractive Index) glass in an innovative way optimizes
the overall distribution of optical power, and also reduces various
aberrations to the absolute minimum while achieving remarkable compactness. In
addition, suitable positioning of two hybrid aspherical elements serves to
maintain imaging performance and to shorten and compress the entire optical
system. Furthermore, an LD (Low Dispersion) glass element is used to
accomplish effective compensation of on-axis and lateral chromatic
aberrations, a critical factor for enhancing optical quality in digital
photography, in order to achieve outstanding optical performance over the
entire zoom range.
Revolutionary Minimum Focus Distance of 27cm (10.6)
over the Entire Zoom Range Affords a 1:4.5 Macro Capability
The new lens achieves a minimum focus distance of 27 cm (10.6) over the entire
zoom range, the best in its class among fast standard zoom lenses with an F/2.8
maximum aperture throughout the entire zoom range used exclusively for digital
SLR cameras with APS-C sized image sensors. The maximum magnification ratio of
1:4.5 at the 50mm setting is the top level in its class.
Optical Design Dedicated to Digital SLR Photography
by Optimizing the Angle of Incidence of Light Rays Reaching the Image Sensor
This zoom lens uses an optical system designed to confine the changing angles of
incidences of light rays reaching the imager within a certain scope over the
entire image field by considering the effects of variance due to zooming.
Enhanced Peripheral Illumination
Peripheral light fall-off is minimized when compared with that of conventional
lenses for film cameras, so images are uniformly bright from the center to the
periphery.
Outstanding Resolution
Since the lens is designed exclusively for digital SLR photography, it provides
high image quality resolution, contrast and flatness of image field .
Internal Surface Coating to Reduce Ghosting and Flare
By employing Internal Surface Coatings (i.e., multiple-layer coatings on
cemented surfaces of plural elements) and new multiple-layer coating technology
on ordinary elements, ghosting and flare due to the reflections that occur when
light enters through the front element and reflections caused by the imagers
themselves are reduced to the absolute minimum.
Large Aperture in Lightweight, Compact Design Thanks
to New Mechanical Devices
Complicated mechanisms are built into the compact body, thanks to new mechanical
devices, for excellent portability and ease of use. In addition, a complex
triple cam structure where cams zoom and focus within a three-layer lens barrel
has been further developed to improve AF focus precision for close-in shots and
torque irregularity when zooming in and out. Additionally, the engineering of
the lens has been completely overhauled to downsize its parts and to increase
their precision and durability, in order to accommodate the complex structure
incorporated into the new SP AF17-50mm F/2.8 XR Di-II LD Aspherical [IF].
Zoom Lock Mechanism Incorporated
The Zoom Lock prevents unwanted barrel extension when carrying the lens/camera
combination.
Flower- Shaped Lens
A glare-reducing flower-shaped lens hood is included as a standard accessory.
The special hood provides optimum shading of superfluous light rays that enter
from the rectangular frame outside the image field.
New External Design of the New Di II Series Conveys
High Performance, High Precision Image
Improvements have been made to the external design by adding a gold-colored band
between the focus and zoom rings to enhance the appearance and make the product
stand out as a Di-II lens. Also, the black coating over the entire lens barrel
creates a high-quality, sophisticated look. The rubber patterns of the zoom
rings have also been improved to complement the digital camera design style and
to provide better handling.
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