I need some help :D

I want to deal with macro photography. I have a EOS REBEL T2i and would like a help on how to start looking for a macro lens. I thought to http://www.macroringfl​ash.com/metz-ms-1/ but I'm not sure if it's the right decision. Thoughts?

Thats a flash not a lens......a lens is the pokey out bit on the front of the camera that focuses the image onto the sensor...
If you google macro lens reviews you should get an idea of what will be best for you.

There are a few Canon macro lenses. They're all good. I have the 100mm f/2.8. The key factor that I considered is the focal length. The longer the focal length, the less likely you will scare away some critters like dragon flies before you can take their picture. With shorter focal lengths you have to get closer. Also essential for macro work is a tripod. Some of the newer macro lenses have image stabilization. Others will tell you how effective it is. With macro, camera movement and hand shake is more of a factor. The ring flash that you mention can be useful because the pop-up flash will be blocked by the lens since you're so close to the subject. Alternatively, you can get one or two external flashes and either fire them wirelessly or put one on a cable.

don123, thanks for the wealth of information in your post.

Yep, your link is a ring light.

You have no reason to stray from Canon for a macro lens. You are already dealing with a hefty crop factor, but the usual advice is to get a longer lens so you aren't on top of your subjects. canon has a 50 I believe, but the 100 seems better, being much newer. There is an IS version, but if you're on a tripod, save the cash (for that ring light!) and get the older version for just a couple hundred. Macros are all sharp. I'd skip the 180 on a crop—you'll be in the next room. if you want 100% on "film" as the original, you need 1:1. my Zeiss's only go 1:2, but I don't shoot macro. I haven't used tubes since the 80s, but they will get you closer.

take your pick, no duds that I know of among the Canon/Sigma/Tamron/Tok​ina these being the most popular brands. 90 or 100mm seems a good compromise between weight and working distance. I use the MP-E65 a lot but thats only because I'm interested in very small subjects like Springtails.