Lens For Canon T2i

I'll add another morsel to the plate, lukkyseven, since you mention wanting to know what else you can do with it.

Macro lenses are also generally great portrait lenses, since they are so sharp. If this is of interest to you, I will point you more towards the 60mm than the 100mm. The reason is, the 100mm will force you to be across the room from the person whose portrait you're shooting, whereas with the 60mm you'll be able to shoot from a much more reasonable distance.

You'll like the 100mm for insects better, for the same reason - you can shoot the bug from farther away, making them less likely to bolt at your presence.

Having to hold off on your purchase is actually a benefit. You now have the time to research how macro lenses work, and develop your picture-taking skills in an environment where the lens won't make up for minor problems with technique.

What's your current level of photographic skill? Are you familiar with your camera's manual settings?

OK, it'll be important for you to learn the basics of manual photography in order to maximize the results you get from a macro lens, or portraiture for that matter. You don't have to be professor-level, just cognizant of what aperture, exposure, ISO and White Balance mean in the grand scheme of things. The settings of those you will use in coin photography will likely be different than how you use them in outdoor shooting, so an overview will make you better understand what's happening.

I like that Tamron 90 as well. It's very sharp, and inexpensive for what you get. It suffers from the same lens-extension thing while focusing, but remember you'll be able to counteract that with the sheer number of megapixels your sensor offers, allowing you to move the camera further away from the coin while getting images the same size as I, for instance, can.

Keep in mind, some of the problems I discuss with distance placement are because I'm always trying to get the biggest-possible image. I want to get something the size of a Cent 2000 pixels wide on my screen. If you're willing to settle for nice, sharp images of 1000px diameter, much of the problem with camera distance will never affect you.

I took the picture I posted above with my 18-55. Is that one satisfactory?

These were the settings: Zoomed all the way in at 55mm. ISO 400, 1/50 sec. exposure at f/8 aperture. If I recall, the camera was about 18" from the coin. I did have to play a little bit in postprocessing to get the color right.

That's another area of learning for you - postprocessing. One can fix a whole bunch of wrong with Photoshop or the Gimp.

While I can't offer anywhere near the expertise of SuperDave , I saw that you are considering the Tamron 90mm lens. I just wanted to say that is the same lens I use and I have been very happy with it. If I remember right it was about $375 or somewhere in that neighborhood and I feel I got a good lens that serves my needs. As far as I'm concerned, it was money well spent.

use the Tamron 90mm... a lot less $$$ tah the Canon.
I am extremely happy with it

I won't disagree with Stunet's opinion of macro add-ons, even though my personal opinion is negative, because he's demonstrated his skill with them and they work well indeed in his hands. Raynox is one brand which I've seen decent results from, kicking around the Internet. Their stuff isn't a whole lot cheaper than a dedicated lens. Other add-on Macros, I don't know enough about to form an opinion.

If you end up saving the money for a second lens, permit me to recommend the Canon 55-250. I's the perfect addition to the 18-55 and far better than a lens of this price ($200-ish) has any right to be.

Not for coins. You end up having to put the coin on one side of the room, and the camera on the other.

Seriously, with the coin at desk height, I have to mount my 450D/100mm Macro so high that the LCD and viewfinder are unusable; I can't reach them. It's no big thing because I shoot remotely from the computer, but someone who didn't do it that way would find it an annoyance.

At 150 or 180mm, you would probably need 24"+ from the end of the lens to the coin. Camera on tripod, coin on floor.