The Sigma 17-70mm F2.8-4 DC Macro O

The Sigma 17-70mm F2.8-4 DC Macro OS HSM is a premium fast 'normal' zoom for APS-C SLRs, which is designed as an upgrade for photographers who have outgrown the 'kit' zooms typically supplied with camera bodies. It was announced at Photokina 2012, as the first lens in Sigma's new 'Contemporary' category of compact general-purpose zooms for everyday photography. It's a successor to a near identically-named lens from December 2009, the Sigma 17-70mm F2.8-4 DC Macro OS HSM, but is smaller and lighter, uses revised optics, and has a new cosmetic design. Prior to this Sigma made the unstabilised 17-70mm f/2.8-4.5 DC, a lens which was very highly regarded in its time.

The latest 17-70mm offers some pretty clear advantages over the average 18-55mm F3.5-5.6 kit lens. It provides extra zoom range, being both slightly wider and usefully longer in the telephoto range. Its F2.8-4 maximum aperture range means it gathers more light - twice as much at the long end, and 2/3 stop at wideangle. This offers advantages for both low light shooting, and getting blurred backgrounds when shooting subjects like portraits. It also offers unusually close focusing to just 22cm (hence the word 'Macro' in the lens name).

The lens use Sigma's 'Hypersonic Motor' for quiet autofocus, and is available to fit Canon, Nikon, Pentax, Sigma and Sony cameras. The Canon, Nikon and Sigma versions all feature built-in optical image stabilisation, to allow shooting at slower shutter speeds than usual without image degradation from camera shake. The Pentax and Sony versions don't have OS, and rely on the camera's built-in stabilisation systems instead. (Note that the lens won't autofocus on old Pentax DSLRs that don't have the requisite electrical contacts to power the focus motor.)

The 17-70mm doesn't have many direct equivalents from the camera manufacturers - the closest is the Pentax smc DA 17-70mm F4.0 AL (IF) SDM - and offers an interesting middle ground between upgrading to an extended range zoom such in the 16-85mm class, or a fast zoom like a 17-50mm F2.8. It's also pretty reasonably priced. So is it the ideal compromise choice, or just too good to be true? Read on to find out.

Headline features
Approx. 26-110mm equivalent focal length range; F2.8-4 maximum aperture
Available for Canon, Nikon, Pentax, Sigma and Sony mounts (APS-C/DX format DSLRs only)
In-lens Optical Stabilization system (excluding Pentax and Sony versions)
Hypersonic Motor (HSM) focusing
0.22m closest focus (0.36x magnification)
Angle of view
The pictures below illustrate the focal length range from wide to telephoto (on Canon APS-C, 1.6x).

Kết quả (Việt) 1:

Sigma 17-70mm F2.8-4 DC Macro OS HSM là một phí bảo hiểm nhanh 'bình thường' zoom cho máy ảnh SLR APS-C, được thiết kế như một bản nâng cấp cho nhiếp ảnh gia những người có outgrown 'kit' phóng thông thường được cung cấp với các cơ quan máy ảnh. Nó đã được công bố tại Photokina 2012, như ống kính đầu tiên trong thể loại 'Hiện đại' mới của Sigma của nhỏ gọn đa năng phóng cho nhiếp ảnh hàng ngày. Nó là một kế để một gần hệt tên là ống kính từ tháng 12 năm 2009, Sigma 17-70mm F2.8-4 DC Macro OS HSM, nhưng là nhỏ hơn và nhẹ hơn, sử dụng sửa đổi quang học, và có một thiết kế Mỹ phẩm mới. Trước khi này Sigma thực hiện unstabilised 17-70 mm f/2.8-4.5 DC, một ống kính mà rất đánh giá cao trong thời gian của mình.17-70mm đặt cung cấp một số khá rõ ràng lợi thế so với lens kit trung bình 18-55mm F3.5-5,6. Nó cung cấp phụ thu phóng đủ, là hơi rộng hơn và hữu ích dài hơn trong dãy Tele. Phạm vi tối đa khẩu độ F2.8-4 có nghĩa là nó thu thập thêm ánh sáng - hai lần so dài cuối, và 2/3 chặng dừng tại wideangle. Điều này cung cấp các lợi thế cho cả chụp ánh sáng thấp, và nhận được nền mờ khi chụp hình đối tượng như gương điển hình. Nó cũng cung cấp bất thường đóng tập trung để chỉ 22cm (vì thế từ 'Vĩ mô' trong tên ống kính).The lens use Sigma's 'Hypersonic Motor' for quiet autofocus, and is available to fit Canon, Nikon, Pentax, Sigma and Sony cameras. The Canon, Nikon and Sigma versions all feature built-in optical image stabilisation, to allow shooting at slower shutter speeds than usual without image degradation from camera shake. The Pentax and Sony versions don't have OS, and rely on the camera's built-in stabilisation systems instead. (Note that the lens won't autofocus on old Pentax DSLRs that don't have the requisite electrical contacts to power the focus motor.)The 17-70mm doesn't have many direct equivalents from the camera manufacturers - the closest is the Pentax smc DA 17-70mm F4.0 AL (IF) SDM - and offers an interesting middle ground between upgrading to an extended range zoom such in the 16-85mm class, or a fast zoom like a 17-50mm F2.8. It's also pretty reasonably priced. So is it the ideal compromise choice, or just too good to be true? Read on to find out.Headline featuresApprox. 26-110mm equivalent focal length range; F2.8-4 maximum apertureAvailable for Canon, Nikon, Pentax, Sigma and Sony mounts (APS-C/DX format DSLRs only)In-lens Optical Stabilization system (excluding Pentax and Sony versions)Hypersonic Motor (HSM) focusing0.22m closest focus (0.36x magnification)Angle of viewThe pictures below illustrate the focal length range from wide to telephoto (on Canon APS-C, 1.6x).