Chico, using extension tubes reduces how much is in focus as well as getting you closer. Macro is very hard to get right because the area in focus is so small, which is why sometimes you get stacked images to make just one (where you takes several photos of the same thing with various parts in focus and they are then literally stacked and blended by software to produce one image (CZ Combine or Zerene Stacker, being the 2 programmes for it).
You can use tubes on any lens, but prime lenses are better (like your 50) as they are usually higher quality glass.
You can use tubes on any lens, but prime lenses are better (like your 50) as they are usually higher quality glass.
