Style:Pentax Digital DSLR Camera
Designed for use with full frame digital SLR cameras. May also be used with smaller APS-c size sensors with a corresponding effective increase in focal length to about 100 to 300mm with most cameras Offers Sigma's OS System (Optical Stabilization) allowing handheld photography even in low-light situation HSM (Hyper-Sonic Motor) ensures a quiet & high-speed auto focus FLD glass elements with performance equal to fluorite glass for compensate for color aberration
From the Manufacturer
Large aperture telephoto zoom lens incorporating Sigma's original Optical Stabilizer function
This large aperture telephoto zoom lens, incorporating Sigma's original Optical Stabilizer function, covers focal lengths from 70mm to 200mm and offers a constant aperture of F2.8 over the entire zoom range. The OS function offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible. It makes shooting easy for many types of photography such as portraits and sports. Two FLD ("F" Low Dispersion) glass elements, which have performance equal to fluorite glass, and three SLD (Special Low Dispersion) glass elements provide excellent correction of color aberration. Super Multi-Layer Coating reduces flare and ghosting. The lens incorporates HSM (Hyper Sonic Motor), ensuring a quiet and high speed AF as well as full-time manual focus capability. It is also possible to attach Sigma's optional APO Tele Converters.
No Optical Stabilizer (top). With Optical Stabilizer (bottom).
Super Multi-Layer Coating
The lens is equipped with Sigma's own unique OS (Optical Stabilizer) function. This system offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible, making telephoto shooting easy. Mode 1 is ideal for general photography and Mode 2 is designed for panning subjects such as racing cars. For Sony and Pentax mount, the built-in OS function of this lens can be used even if the camera body is equipped with an anti-shake function. As compensation for camera shake is visible in the view finder, the photographer can easily check for accurate focus and ensure there is no subject movement.
* For Pentax and Sony mounts, it is not possible to use the AF and the built-in OS function of this lens when attaching it to film SLR cameras as well as Pentax ist series and K100D.
* When using the OS function of a lens with a camera which incorporates a stabilizer unit, please turn the camera's stabilizer unit off.
* This lens cannot be used with film SLR cameras with the exception of the Nikon F6 and Canon EOS-1v.
This lens has a compact construction with a diameter of 3.4in, overall length of 7.8in. and weight of 50.4oz. This compact and lightweight construction makes it ideal for many types of photography such as portraits, landscapes and sports.
No Super Multi-Layer Coating (left). With Super Multi-Layer Coating (right).
Excellent Optical Performance
This lens features two FLD ("F" Low Dispersion) glass elements, which have the performance equal to fluorite glass, and three SLD (Special Low Dispersion) glass elements providing excellent correction of color aberration. The Super Multi-Layer Coating reduces flare and ghosting and ensures high contrast images. High image quality is assured throughout the entire zoom range.
* FLD glass is the highest level low dispersion glass available with extremely high light transmission. This optical glass has a performance equal to fluorite glass which has a low refractive index and low dispersion compared to current optical glass. It also benefits from high anomalous dispersion.
These characteristics give excellent correction for residual chromatic aberration (secondary spectrum) which cannot be corrected by ordinary optical glass and ensures high definition and high contrast images.
Hyper Sonic Motor
High speed and quiet AF
HSM indicates lenses equipped with a Hyper Sonic Motor, driven by ultrasonic waves. Incorporation of HSM (Hyper Sonic Motor) ensures quiet and high speed autofocus, while allowing full-time manual focus override.
* For Sony and Pentax mount, AF will not function with DSLR cameras that do not support HSM.
This lens has a rounded 9 blade diaphragm which creates an attractive bokeh to the out of focus area.
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.
|Lens Construction ||22 Elements in 17 Groups |
|Angle of View ||34.3 - 12.3 degrees |
|Number of Diaphragm Blades ||9 Blades (Rounded diaphragm) |
|Minimum Aperture ||F22 |
|Minimum Focusing Distance ||140cm / 55.1in. |
|Maximum Magnification ||1:8 |
|Dimensions ||Diameter 86.4mm x Length 197.6mm /3.4in. x 7.8in. |
|Weight ||1430g / 50.4oz. |
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.
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 amount show a minus value, the image will be seen as expanded (Barrel distortion). If the distortion amount 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.
The horizontal axis shows the image height (the distance from the center to the edge of the image [mm]). The vertical axis shows the amount of light in the image (based on the amount of light in the image center being 100%). If the peripheral amount of light is lower than the center, the four corners of the image will be darker (vignetting).