It’s quite often that this question is asked when evaluating which camera to buy, and is made especially difficult due to the almost $200 more you’d have to shell out for the 30D.
The following is a short list of feature and specifications improvements found in the Canon 30D digital SLR camera. Bear in mind though, for the most part, the 20D is equal to the 30D in the image quality department, so you’d have to ask yourself if the improvements in features available in the 30D justifies the price differential.
- A larger and more usable LCD screen on the back of camera
- A new metering option, spot metering is now available
- A larger buffer size and the 5 fps option when shooting.
- 5 frames per second adjustable to 3 fps if needed
- The ISO value can be displayed in the viewfinder
- RGB histogram — great for evaluating if any color channel is blown
- More available ISO stops (values)
- Better file management — a new folder is created in-camera only after 9,999 pictures (the 20D creates one after every 99 images)
- Improved body grip
You can read more at the following discussion threads: Link #1 | #2
You might like to quickly check out available deals and current prices for various body-only or other configurations:
Canon EOS 20D | Canon EOS 30D
… but bear in mind that the offers quoted are for new equipment only. You’ll probably be able to find great deals for used equipment in the used market.
My personal recommendation would be to spend a bit more and get the Canon 30D for the improved features and specs.
Read Brian’s experience on upgrading to the 30D from the 20D.