Lenses

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Cons: For my copy, an unusual faint noise while zooming, just noticed it after a month of using it. No manual focus override when in AF mode. When in AF mode, focus ring moves.

Pros: Image quality, contrast are excellent. AF is fast and accurate. But since this is a variable lens, the focus result is sometimes not correct due to changes in the focusing plane of the lens itself. Built of this lens is excellent for the price you pay, i like the size and compactness, weight is a little heavy but is fine due to expensive glass used.

Summary: Excellent lens for the half price of other major brands like Canon, etc.

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Cons: Awesome sharp from 2.8 can be a little soft at extreme edge, but with that conditions of light only Canon L IS Lense on a full frame can do same!!! Good build quality (like L lense)Very sharp at the center at all focal lens Sharp across the frame when stopping down to f4

Pros: No manual override focus

Summary: Get ride off my 17-40 F4 L and very pleased with this Sigma and would recommend to anyone. Couldn't use the Canon in interior, only with flash build-in off the camera Is as good or better as similar Canon 17-55 2.8 IS for a little more than half the price

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Cons: Dust easily stuck on lens body - harder to clean

Pros: Sharp, Contrasty, OS works, Value for money, Good build quality

Summary: Best price performance compared to Nikon 17-55, Tamron 17-50, Tokina 16-50

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Cons: focus ring turns during autofocus. no full time manual override like in other HSM lenses. Lenshood is not very well done and appears to be of cheap build quality.

Pros: Very sharp, even wide open. good build quality. well working optical stabilization. pretty quiet autofocus due to HSM

Summary: Had the Tamron 17-50 2.8 non OS before an d sold it after a week. The Sigma really delivers in terms of sharpness and autofocus speed (two thing where the Tamron failed me). On top having OS is a nice feature

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Cons: No full-time manual focus, but at a considerably less price point than Canon 17-55/2.8, so this is ok. Occasional mis-focus, but keeper rate is satisfactorily high.

Pros: Somewhat soft from f/2.8, but usable and becomes noticeably sharper by f/4. Quiet AF. Wonderful colors and contrast.

Summary: I use on Canon APS-C. This Sigma beats the socks off the Tamron 17-50/2.8, which I owned and despised due to its loud AF and that the Tam hunted for focus in low light. I like that it's a much more compact lens than the Canon 17-55/2.8.

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Cons: Awesome sharp from 2.8 and across most the frame Light weight lense

Pros: None for this price

Summary: Highy recomend, a little better them the 17-40 F4 i had before

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Cons: Focus ring rotation in front if that upset you. No manual focus override, but the button for change it in a good position.

Pros: Amazing sharp at center from 2.8 From F4 is sharp from center to extreme border, the OS works very well.

Summary: Very sharp lense with and Extra L sharp at center, very fast focus. I´ve tested in low light and it was great no back focus. Recomend for sure

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Cons: A little heavy

Pros: Very sharp, autofocusses precisely. Affordable 77mm filter diameter. Build quality seems very solid.

Summary: Very happy with purchase; this standard zoom takes photos that match up to the quality from my prime 30mm and 50mm lenses

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Cons: That focus ring...

Pros: Excelent image quality, good AF, good stabilization

Summary: Probably the best ratio price/quality in this category

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Cons: Clumsy manual focusing

Pros: Seems as good as similar Canon for a little more than half the price.

Summary: Nice piece of glass

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Cons: Not weather sealed

Pros: Solid build lightweight compared with Nikon Close minimum focal distance Sharp? OMG - this lens is sharp HSM v quiet and quick

Summary: This is a really excellent lens - great value for money but not at the expense of quality

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Cons: AF not accurate on 17mm

Pros: Sharp wide open, OS

Summary: Focus on 17mm is lottery

Build quality
Optical quality
Value for money
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Cons: Soft image at the frame edge at wide open Focus ring rotates during AF No full-time override manual focus Focus not so accurate at widest angle

Pros: Good build quality Very sharp at the center at all focal lens Sharp across the frame when stopping down to f4 onward Small and light Lens hood included and nice soft case

Summary: Good quality and recommended lens for its price.

Build quality
Optical quality
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Overall

Cons: Its heavy compared with plasticky kit lens (18-55mm Canon).

Pros: Fast 2.8 which slows to a respectable f4 at the tele end. My copy is sharp throughout the range and you really have to look for distortion at the wide end. The macro feature is a big plus when you want casual closeups of flowers and other objects and do not need true Macro (1:1). Everything smooth as butter--ultra fast focus. Nice Bokeh and I do not notice any chromatic aberrations until zooming in on details using my computer. The OS feature works extremely well and gives nothing away to Canon in this area.

Summary: Value 5 Stars. Everything else is very good at 4 stars. I am pleased with my purchase and would recommend to anyone.