Originally posted by Kendra59 I have always been interested in macro photography, but have no experience with it. A recent purchase of Pentax K-50 camera and the two kit lenses has whetted my appetite for more. Unfortunately, I am not able to go out and buy the best in new macro lenses. I would like advice on which makes and models of macro lenses that perform well, but sell on the used market for $250 or less. My understanding is macro photography must be done using a tripod for clarity, so the weight of the lens won't be too much of a factor. The Pentax K-mount lens pool is extensive; what are the hidden macro gems to look for? I am open to all brands that fit a K-mount...
Some good advice has already been given, but here are other tips
1) the least expensive way to get into macro and deep macro are the Raynox DCR 150 and DCR 250 clip-on achromatic close up filters. The 150 brings any lens to focus @ 8 inches, the 250 to four inches. The exact magnification depends on the focal length of the lens. These units give amazing quality, but it depends on the quality of the lens to which they are attached. They can provide excellent IQ with a good zoom lens. There is a thread on PF devoted to these adapters. Search it out and see what these little gems can do.
2) the 90mm Tamron macro, already recommended by others, has been an excellent macro lens since its introduction. Most macro is done with manual focusing, so even going back to the Adptall II version you will get a fine lens.
3) All versions of Pentax 50mm macros are excellent. I had their very first macro, a 50mm f4.0 preset, and it is still used by Pentaxians who post on this thread. The 50mm f2.8 SMCA is beautiful mechanically and excellent optically, but many criticize it for only going to 1/2 life size.
4) When you get closer than 1/2 life size in macro you're entering a different realm. Tripod or other sturdy support is important unless you're using a strobe, and a focusing rail is almost a requirement. When you go to greater that life size, a focusing rail of some kind is indispensable, and depth of field is a really big problem. In this realm, reverse-mounting a short FL lens, or coupling two lenses is more practical and usually provides better IQ than simply extending a lens with tubes or bellows.