Teleconverters, extension tubes, macro lenses, etc... Worth buying any??

[AXIS]

I currently have the 18-55mm kit lens and a 55-300mm lens. The zoom from the 300mm has been lots of fun and has really allowed me to get some of the shots I could before (wildlife and such). I still find myself wanting more zoom and a better setup for macro. Ive seen some info on reversing lenses for macro, "filter" mounted lenses/attachments, and other tubes and what not but I dont really know what is what. Are any of these worth actually buying or are they just expensive paper weights? Im hoping to find a cheap(ish) option for getting a bit more distance out of my 55-300mm and maybe some better macro shots from either lens.

 

[Judobreaker]

Extension tubes are useful for macro.
They do not affect image quality as they have no glass. The only real disadvantage they have is that you lose some light while using them so flash usually comes in handy.

There's some macro filters (Raynox I think) which work well too. There are several users on this forum that use them and I've seen very good results from them.

Reversing lenses also works well for macro, however it has some tricky disadvantages.
Because the lens is mounted in reverse this means the camera can not control the lens at all. You won't be able to set the aperture using the camera so unless your lens has an aperture ring you won't be able to set the aperture at all.
I think I've seen a device which connects a reversed lens to the camera sometime, but I'm not sure as to how well this works and how much it costs.
If you happen to have a lens with an aperture ring (the Nikon 50mm f/1.8D lens has one for example) you could try this quite easily.

A teleconverter would work for macro too in some sense. I'm not sure how well this would work on a non-macro lens (usually they are used in combination with a dedicated macro lens) but technically it would increase magnification.
The downside is however that a teleconverter degrades image quality. This might not always be a problem with more expensive teleconverters in combination with dedicated macro lenses (which are really sharp usually) but on lenses of less quality you'll be enlarging any lens problems, even if you use expensive teleconverters.
You would also be able to use this for a general wildlife focal length increase though so you would get a 2-in-1 bonus.
I'm not sure if I'd be happy with the quality though, I haven't tried myself but from what I've heard and seen using teleconverters is tricky business...

 

[SCraig]

Teleconverters have their place but if you think you're going to plunk a 2x TC on the end of that 55-300 and get a nearly free 110-600 out of it then think again.

First, the Nikon TC won't work with that lens so you are limited to third-party choices. No big deal, the Kenko Pro series are excellent teleconverters. There are others as well, but I know that the Kenko Pro (as opposed to the "Standard" series) are very good.

Next, a 2x teleconverter is going to cost 2 full stops of light so that 55-300 f/4.5-5.6 lens is going to become a f/8-11 lens. Going to a maximum aperture of f/8 is probably going to prevent your autofocus from working as well. Most cameras don't autofocus well with a lens having a maximum aperture of f/5.6 or more, however I do use my Sigma 150-500 and a 1.4 TC regularly and can get it to autofocus as long as there is plenty of light. Not always, but usually.

And finally, the resulting image quality using a 3x teleconverter is usually rather poor. How poor depends entirely on the quality of the teleconverter. I have a lousy 2x TC and the image quality on every lens I own is so poor I refuse to use it.

My recommendation is to stick with a 1.4x teleconverter, and get the best quality you can find. That combination works well for me. It isn't perfect, I still lose a lot of image quality, however sometimes the difference in image quality is offset by not having to crop as much.