Excerpt: For APS-C shooters who covet the fast, image-stabilized 70–210mm zooms for full-framers, Sigma provides the sole choice. This 50–150mm f/2.8 OS lens ($1,099, street) replaces a similar but nonstabilized lens in Sigma’s catalog. Its EX designation points to a pro-quality optic, and the specs support that: Internally zooming and focusing, with six SLD glass elements for sharpness, it focuses quietly and includes a removable tripod collar, which the older 50–150mm lacked.
Conclusion: A solid build quality that we have become accustomed to from the Sigma range and still light enough for handheld, OS remains sharp with a fixed range, wide aperture usually reserved for pros. Perfect for those who require the power without the money, competing well against full-frame equivalents under the same situations.
Pros: Fixed f/2.8 aperture, Four stops OS, Pro focal range, Lightweight for a telephoto
Cons: Too large for most hobbyists, Only for crop sensor, Vignetting
Excerpt: This new f/2.8 telephoto zoom from Sigma is the answer to many photographers' prayers. As lenses go, this one is rather short on what you could class as key features, but that doesn't mean that it's below par. In fact it sets the benchmark on what a telephoto zoom should offer. The 50-150mm is a digital-only lens and effectively gives you a focal length of 75-225mm making it much more versatile than the 105-300mm (approx) that a 70-200mm focal length will provide.
Conclusion: So which lens you should choose? Sigma 70-200 f/2.8 or Sigma 50-150 f/2.8? First one has better optical performance, especially on APS-C/DX matrix. Astigmatism, vignetting and distortion are well controlled which is not in case of 50-150 model. But all in all advantage of 70-200 is not that big. Besides 50-150 mm is cheaper and much smaller and lighter.
Cons: poor image quality at the edge for 150 mm,, chromatic abberation should be smaller in APO lens,, noticable astigmatism for focal length range from 100 to 150 mm,, clear vignetting especially at 150 mm,, significant front-focus with Canon 20D.
Sigma AF 50-150mm f/2.8 EX DC HSM (Nikon mount) - Review / Test Report
10 November 2006
Conclusion: The Sigma is an impressive lens with only few weaknesses. The resolution is excellent at 50mm and 100mm and (roughly) very good at 150mm although the quality could be a little better at f/2.8 here. While not formally tested the close focus performance (@ 150mm <1.5m) seems to fairly poor. Distortions and CAs are well controlled. Vignetting is a slight problem at 150mm @ f/2.8 only. The bokeh (out-of-focus blur) is pretty good especially for a zoom lens.
Summary: With a compact size and weight alleviating the need for a tripod collar and the third generation of Sigma’s HSM focussing motor making the AF very quick, the lens is fast in every sense and easy to handle. Smooth operating control rings add to the feel of a nice lens that should find it’s way into a good number of kit bags!
Pros: Excellent optical performance, Very good handling with fast AF, Compact with a supplied hood.
Cons: Slight fall-off in resolution at the longest focal length., Distortion just noticeable at 150mm.
Excerpt: 1. Opis Sigma APO 50-150 mm F2.8 EX DC HSM spada v Sigmin EX pro razred objektivov. Oznaka DC nam pove, da je namenjena izključno fotoaparatom s senzorjem APS - C velikosti, HSM pa, da ima vgrajen ultrasonični AF motorček. Ta nam zagotavlja tiho in hitro ostrenje, hkrati pa lahko z obročem za ročno ostrenje v vsakem trenutku »povozimo« AF. Goriščnica objektiva, preračunana na polni format znaša 80-240 mm ( v našem primeru testiranja na Canon EOS 400D).
Pros: Ostrina pri vrednostih zaslonke od f4 do f8, Tiho in hitro ostrenje, Zgradba ohišja, Cena, Zelo dobra dopolnitev širokokotnega objektiva (ki je ponavadi v rangu 17/18-50/55mm)
Cons: V določenih primerih izrazita kromatska aberacija, Ostrina pri zaslonki F2.8