Yet another awesome lens by Sigma! I have yet to try it out outdoors but my tests from indoors are very promising! As always, Walmart has the best prices and service!!

I have owned this lens for about a year now. I am very pleased with the images I get from it. I have found it hunts whilst focusing in grass or trees. I tend to use manual focus 10% of the time because of this slight problem. I would not say it is a fault.

BEAUTIFUL LENSE, WORKS PERFECT FROM 300MM AND BELOW A LITTLE SOFT FROM 300-400 .. FAST AUTO FOCUS EXTREMELY SHARP, A BIT HEAVY, BUT IST A BIG LENSE (EXPECTED) ZOOM RING IS KIND OF HARD WHEN ZOOMING OUT( COMPARED TO NIKON LENSES)..

A definite step up from Canon 70-300 IS USM only if you are comfortable with the two extra pounds. If you don't have at least a good monopod, you will need one. I can, however, get useable hand held shots at 120th of a second at 400mm with optical stabilization on.

Super tele lenses (400mm+) tend to be rather expensive being and as such often limited to professional use. However, there're a few lenses where the manufacturers were able to keep a rather moderate price level and the Sigma AF 120-400mm F4.5-5.6 DG HSM APO OS is surely among to more popular options...

I do not currently plan to create a full text review for the Sigma 120-400mm f/4.5-5.6 DG OS HSM Lens, but the full array of standardized tests are available for your own evaluation and comparison with similar lenses.

I had read mixed reviews on this lens and wasn't sure if it would be the best choice for my needs. I do mostly wildlife photography and needed a long reach lens. After driving myself crazy, I finally chose to buy it over the more expensive Canon 100-400 IS. I was amazed for so many reasons.

Very well balanced; excellent IQ; positioning of the manual ring and zoom ring

A bit heavy; but not much different than others in this class

Nature photographer Ross Hoddinott puts Sigma's 120-400mm zoom to the test and is impressed by its versatility Sigma announced its 120-400mm lens in January 2008, along with the 150-500mm f/5-6.3.

A 3.3x zoom lens covering super-telephoto focal lengths, with optical stabilisation to aid hand held shooting.

Priced well; Good build quality; Optical Stabilisation; Silent focusing with full-time manual override

Prone to flare when used without the supplied lens hood; Loose zoom mechanism suffers with zoom creep; Hunts for focus in low light conditions

Not a bad lens for the money this Sigma can be quite sharp and reasonably quick to focus if you know how to use it and your camera to their maximum potential. This is not a point and shoot type of lens , it does require your input to get the best out of it.I found it quite heavy when lugging it all...

Cost effective; High build quality; Smooth focusing; Quiet,accurate HSM AF motor; Great adjustable tripod leg mounting shoe; Zoom creep lock

Soft wide open at maximum zoom/aperture; Heavy; Autofocus can hunt a bi,t but once locked on to the general target area is very fast