Automatic said:
Sorry but I don't have a clue what a full frame camera is. And what lenses would work on a 30D as well as "full frame " cameras.
OK, here is a quick lesson.
Are you familiar with 35mm film? It has been the standard consumer film for a few decades. Camera makers (like Canon & Nikon etc.) have been making 35mm cameras and lenses for many years. Now along comes digital technology and the camera makers come out with Digital SLR cameras (we won't sorry about point & shoot digi-cams). DSLRs are very similar to film SLR cameras except that instead of film behind the shutter, there is a digital sensor.
Point & shoot digital cameras (actually almost all non-SLR digital cameras) have small sensors, about the size of a finger nail. These are cheaper to make but the image quality is not really great. The camera makers put bigger sensors into DSLR cameras...but it was still too expensive to make the sensors the same size as 35mm film. Thus most of the DSLR cameras have sensors that are bigger than the finger nail ones but smaller than 35mm (or full frame) film.
OK, but what does that mean? Well, this is meaningful because since the DSLR cameras are very similar to the film SLR cameras...they can use the same lenses (in most cases). Imagine light coming through a lens...it projects an image circle that is big enough to cover 35mm film (because that's what it was designed for). Now imagine that same image circle but instead of film it's hitting a digital sensor...and the sensor is not a big as the 35mm film. All the sensor is going to see, is a smaller portion in the cetre of the image. Therefore, the image is essentially 'cropped' by the sensor.
"So what?" you say...well you don't really have to worry about this. All you need to do is to put a lens on your camera and shoot what you see. However, you will have trouble seeing a wide view through the camera...because the smaller sensor has cropped off the outsides of the image circle. (this is why camera makes have made special "wide" lenses that have a smaller image circle...Canon EF-S lenses for example.)
As technology gets better, it's getting cheaper to make bigger sensors...and bigger is better. The Canon pro level DSLR cameras (EOS 1D etc) & the EOS 5D, have sensors that are the same size as 35mm film...thus we call them "Full Frame" because they can use the whole image circle from lenses that were made for 35mm film. The digital only EF-S lenses will not work on these cameras...their image circle is just too small. Also, the EF-S lenses stick back into the camera farther than EF lenses...and the mirror would get in the way.
So, back to the original question. The 10D is an odd ball because it has a sensor smaller than 35mm film, yet it was not made to use the digital only EF-S lenses. You could get a 20D or 30D or one of the Digital Rebel cameras that do let you use these EF-S lenses. However, because bigger is better, you might one day want to upgrade to a 'Full Frame' camera...and if you have invested in EF-S lenses...they will not work on the new camera. This is why some people buy cameras like the 20D but don't like to buy EF-S lenses because they want to upgrade to Full Frame someday.