Summary: Yes it's slow, noisy, and then there's the lens hood issue, (lens hood doesn't fit when the lens cap is attached). That's the bad news, the good news is this lens is razor sharp and super accurate. I use it on a full frame Canon body to produce beautifully clear images. Because of this lenses sharpness and precision I suggest using a tripod when doing any 1 to 1 macro work.
Summary: Initially I thought I bought the best lens so far. It was sharper than my 50 mm Canon f1.8 lens. Then one day while I was shooting I forgot to tighten one of the legs on my tripod. My camera with Sigma 70mm attached to it fell down on the wooden floor. The lens had the hood attached to it. So it didn't hurt any of the glass part or the front part.
Good for product photography, but not for 1:1 macro
David Siegfried, Amazon
26 April 2013
Summary: I purchased the Nikon mount version of this lens, primarily for product photography in a tight space. It works really well for that, as it focuses seamlessly from infinity down to 1:1 macro magnification with no breaks, or gaps in the field of view, that you might get using a macro ring. And it doesn't make you switch to a special "macro mode" as some zoom "macro" lenses do. This lens simply allows you the freedom to shoot at literally any distance you want.
Versatile focal length, good build quality, excellent image quality
26 March 2013
Summary: I've been looking at this lens for quite some time, and it's not disappointing at all. The 1:1 magnification and 70mm focal length make this a double duty lens, great for portraits and macro and product photography. The weight is just right it feels like a well made dense lens, the quality expected for an "EX" class Sigma lens. Focusing is accurate, very quick considering the focus throw, limiter switch is useful and sharp at 2.8 but very sharp at f/4. Highly recommend.
Summary: I actually purchased this from Bic Camera in Japan. I am using it with my Canon T4i and am quite happy with the way it is performing on the Macro end and quite surprised that I can use it for portraits. Nice solid build and yes the auto focus is a bit slow but most of my shots are manual focus so it is not an issue.
Summary: I had MANY dedicated macro lens in 30+ years of photography- mostly because a prime macro is considered to be the sharpest lens. You can shoot anything with them, the clarity is just amazing and at a fraction of the price you have to pay for Big Names- Zeiss, Leica, etc... You can find many reviews like photozone, dpreview, photozine, and so on that can testify about them but I would always prefer those with an MTF chart, like photozone.
Summary: This lens can get you within about 3" of a tiny subject and affords stunning detail, even with the 12 mp limitation of my Pentax K-r. If you're ordering a macro lens, you already know what it's for - this one will do the job brilliantly. At 70mm it's a little long for some applications, especially on an APS-C camera, (which brings your field of view down to the equivalent of a 105mm lens.
Summary: It is sharp. It is the sharpest lens I own, just a little more than the 135 STF. The reputation this lens has for corner to corner sharpness is well deserved (I have an APC sensor but I have no reason to doubt the reviews done with full frame sensors). The autofocus is extremely accurate (but see notes below). Even at f/2.8 and near 1:1 magnification, it nails the focus. Manual focus is made much more accurate by the 270 degree rotation of the focus ring.