Grainy image tells me the video was captured under poor lighting conditions. This is common to all consumer grade camcorders with small lens diameter (less than 60mm) and imaging chip(s) (smaller than 1/5" or so). To improve video quality under poor lighting conditions, you can either turn on the lights, use a video light or get a camcorder with larger lenses and imaging chips.
Another common trait to consumer hard drive and flash memory camcorders is "pixeling". Since the video is very highly compressed, and in order to do anything with the video, step 1 should be to decompress the video, you are much better off by starting with a less-compressed video file when the video is captured. In the case of consumer hard disc drive and flash memory camcorders, there is a "video quality" setting in the menu. If you capture "high quality" video, this will be less compressed than if you wnat the hard drive to record a lot of video (which is sometime called "LP" mode).
Since we cannot see what you see and we do not know what steps you are taking between getting the camcorder video to the DVD, it is a bit of a challenge to provide much more help...
If the video you captured was outside on a bright sunny day and was grainy, then there is likely something else going on. ALL camcorders can take good video outside on a bright sunny day. The easy resolution with either of these camcorders is to turn on the lights or use a video light.
Both the Panasonic H80 and Sony DCR-SR47 use a 1/8" imaging chip. Both carry a 6 lux "rating" for low light when a slow (1/30 second) shutter is used (typical for auto mode in low light). The H80 has a 37mm diameter lens filter size; the DCR-SR47 has a 30mm diameter lens filter size.
These are competing products, and I would not expect much difference in the video quality when the video is captured under the same conditions.
If you want better assurance of good/acceptable video image quality under a wider range of environmental conditions (i.e., low light), then you will need to get bigger diameter lenses and imaging chips than what you find in entry-level consumer camcorders... and use less compression of the digital video stream when capturing the video. These higher-end camcorders (with larger lenses and imaging chips) will be a lot more expensive than the SR47 and H80 combined.
