I'm heading to Costa Rica in a few weeks, and figure there will be a lot of interesting critters and flowers and stuff to check out, so I'd like to try my hand at a bit of macro.
I'll be taking a 40D, 17-55 IS, 24-135 Tamron, and a 100-400L. For weight reasons, (hiking) I'm probably going to leave my tripod (ouch), 50 f1.8, and flash at home. This is not really a photo vacation, just a vacation that will allow some photos....
So... what are my options for low cost, and light weight additions to my bag ? I'm thinking extension tubes, but I'm pretty confused on what they actually do... and what I can expect from them with the lenses I have to work with.
The Tamron's magnification factor is supposed to be 1:3.3, so is probably my best bet, but if you say so, I could leave it behind and take the flash.
Really, there is no substitute for a true macro lens IMO. The ability to focus anywhere from 1:1 up to infinity is really nice. Extension tubes and close-up lenses are handy, but don't allow you to have infinity focus. So you end up doing more swapping of things.
My recommendation would be the EF-S 60mm macro because it's a nice focal length for other purposes than macro, is light, small, fairly inexpensive, and optically excellent.
You can swap it with one of your other lenses faster than you can get extension tubes on or off of another lens (and get that lens on or off of the body) and you may find that you can leave it on the camera more of the time because it's such a nice FL for portraits and just short telephoto work.
On the other hand, a close-up lens is handy on a zoom because your subject remains in focus as you zoom. And you don't lose much light. So I prefer a good quality close-up lens to extension tubes - especially on a zoom. So perhaps a Canon 500D to fit your 24-135 might make for a handy setup. But again, you'll spend some time getting that filter on and off of the lens because you won't have infinity focus with it in place. I wonder if someone makes a bayonet or "snap on" mount ring for close-up lenses
When I think about hiking and travel, I think a LOT about lens swaps. I hate swapping lenses when I'm already pressed for time and feel that I'm holding up a group (or the family). So for me, zooms are nice as are any lenses that can remain on my camera more of the time.
The EF-S 60 is, for me, a lens that I can do a lot with, so that's why I recommend it over the longer focal length macros or, in this case, extension tubes or the like.
Will you have time to stop, set up for a shot, and be able to take it? Or will you be with a fast-moving group? If it's the latter, I'd expect to get a lot of use from the 17-55 and the 24-135. But if it's the former, then all of your gear will probably come in very handy and then it's mostly a matter of weight and size.
