Im jealous of all the beautiful macro shots people are taking. Alas, I am a poor starving student and cannot afford to buy a real macro lens. I have seen items called close up macro filters that screw in just like regular filters but can change the focal length of a pre-existing lens to make it like a macro lens. Does anyone know if these are any good?
1) Macro lens
Since you say you can't afford this, we'll leave it out of the discussion.
2) Screw-on filters
These shorten the minimum focusing distance so that you can get your lens closer to the subject. Works best on a long lens (e.g. 200-300mm range), can be stacked for more power. Make sure you get a double-element macro lens like the Canon 250D or Nikon 4T... the cheap single element ones like Hoya brand tend to have lower image quality and more CA.
3) Extension tubes
These fit at the back of the lens (like teleconverters), and also help your lens "close-in" on the subject. Works best with short lenses (e.g. 50mm) and there's no loss in quality since you aren't stacking additional glass. I've seen a Kenko set of extension tubes sold at B&H for $120, I believe....
4) Reverse lens
Get a fast prime around 50mm length, reverse it and attach it to your lens with a macro coupling ring. Can get very, very high magnification with long lenses, BUT very limited in application because of the high magnification and extremely short working distance (1-4cm).
EDIT:
Some samples with close-ups and macro filters from my Olympus C-750UZ:
How can I make a reverse lens in a F717(58mm) with a 50mm lens?! All the coupling rings I that I found are for 58mm-52mm... Will it work in the same way?!
How can I make a reverse lens in a F717(58mm) with a 50mm lens?! All the coupling rings I that I found are for 58mm-52mm... Will it work in the same way?!
By "50mm lens", it means that the "focal length" of the lens is 50mm, not the "filter size". You can find a variety of 50mm lenses with all sort of sizes... e.g. the Canon EF 50mm f/1.8 MkII is 52mm-threaded, whereas the Canon EF 50mm f/1.4 is 58mm-threaded.
Also you can use step-up or step-down rings if you cannot find a macro coupler with the correct size.
You can get combinations of lens reversing rings and step up/down rings from B&H Photo.
For the 50mm lens, you can use just about any decnt quality 50mm lens. Like an old Canon FD or Nikkor AI lens. It doesn't need to be AF or the latest and greatest.