Yes, The
58mm Canon Close-up lens 500Dwill help but it will only help you focus from 500mm which probably won't get you the magnification you want. Other "close up filters" are junk and not worth wasting money on.
The
T1i Kit comes with the
EF-S 18-55 f/3.5-5.6 IS Lens Lens which the specifications show the close focusing distance to be 250mm (~ 10") with a magnification of 0.34x. So an image of a "marble" at 10" as you see on the LCD will appear .34x life size on the sensor (in other words if the marble is small in the LCD it will be small on the sensor).
In order to get a larger image you need to be able to focus closer. A macro lens will do this but a less expensive option is a set of
extension tubes which are just hollow tubes that move the lens away from the body but maintain electrical contact for Auto Focus & aperture. Optical law states that the magnification is the focal length of the lens divided by the extension length so to get life-size on the sensor at a focal length of 55mm you would need 55mm of extension. Canon sells 12mm and 25mm extension tubes but you can get a set of 12mm, 20mm & 36mm extension tubes from Kenko for less than the price of both Canon tubes.
Note that the extension tubes will not work at the wide angle end of the lens (say 17 - 28mm or so) but you typically want to use the long end of the range anyway.
Using extension tubes, a Close up lens or a macro lens you should still use the following tips to get sharp images:
- manually focus (live view is very useful)
- a tripod or beanbag - i.e. don't hand hold
- a cable release or the 10s timer
- possible use the "mirror lockup" custom function
There are many books on macro & micro photography - Bryan Peterson's
Understanding Close-up Photography is a fairly recent book from a knowledgeable author and can probably be found at your local library
