The Sigma 105mm F/2.8 Macro EX DG is one of the best deals I have ever come across in my short time in photography. I think that the 90-180mm range of macro lenses are some of the most versatile lenses. They are usable for a lot more then just macro, they can do great portraits, wildlife, action, and just anything where you need the most amount of detail. With most macro lenses starting out at F/2.8, they are great for shallow depth of field, but also stop down to as far as F/45 so you can get as much of your subject in focus, an importent thing when doing macro photography. I got my lens for only $300 in mint condition and I would recommend it to everyone, but not without warning. The autofocus was alright when it was on my T1i, but when using my 5D MKII, a lot of my shots have been out of focus and I have had to check my focus with live view. I don't know if it is an electronics problem or if it is that my 5D and lens are on oposite spectrums of the autofocus tolerance and I need to do some micro adjusting. But while the autofocus is bad, this lens is great for video as it has a very smooth focus ring that is a joy to turn. For portait this lens is great at around 3.5 this lens is great for portait as it give enough depth of field but still has pretty circular bokeh, it is importent to remember this lens only has eight straight apature blades rather than a nicer nine rounded. Overall sharpness and performance of this lens is great and I would recommend it to anyone who is looking to get into macro as this lens serves so many purposes, you will definitely get your moneys worth out of it.
Movie shot with lens in combination with 50mm 1.8
Nature
Wildlife shot
http://www.flickr.com/photos/66627224@N02/8276147216/#in/photostream
http://www.flickr.com/photos/66627224@N02/8210395424/#in/photostream
Portrait
http://www.flickr.com/photos/66627224@N02/8107624722/#in/photostream
Macro
http://www.flickr.com/photos/66627224@N02/8101755629/#in/photostream
http://www.flickr.com/photos/66627224@N02/8355912864/#in/photostream
http://www.flickr.com/photos/66627224@N02/8354838679/#in/photostream
Action
http://www.flickr.com/photos/66627224@N02/8355902460/#in/photostream
Movie shot with lens in combination with 50mm 1.8
Nature
Wildlife shot
http://www.flickr.com/photos/66627224@N02/8276147216/#in/photostream
http://www.flickr.com/photos/66627224@N02/8210395424/#in/photostream
Portrait
http://www.flickr.com/photos/66627224@N02/8107624722/#in/photostream
Macro
http://www.flickr.com/photos/66627224@N02/8101755629/#in/photostream
http://www.flickr.com/photos/66627224@N02/8355912864/#in/photostream
http://www.flickr.com/photos/66627224@N02/8354838679/#in/photostream
Action
http://www.flickr.com/photos/66627224@N02/8355902460/#in/photostream