SONY Hi-8  vs  VHS

VIDEO QUALITY
When it comes to in-cruiser video performance, the quality of the images it gathers may be the most important test of all. The quality of the systems recordings depends largely on the format it uses.

Boil it down and the video quality of a format is directly related to  the quantity of information it can pack onto the tape. More information translates to better detail, which, makes for better images. We quantify a formats ability to record detail by measuring how many light-to-dark transitions it can record across the screen. This is called a formats horizontal resolution.

The format that records the least amount of video information is VHS. This format delivers just over 200 lines of horizontal resolution, which is about one third less detail than cable TV.

When engineers figured out how to pack more information on a tape, the Super VHS and Hi-8 formats were born. These hi-band formats record almost twice as much information as VHS. The Sony Hi-8 format can deliver 400 lines of horizontal information.

SOUND QUALITY
A video that looks good and sounds bad is a bad video. The format you use can make a significant difference in how your recording sounds as well as looks.

As with video quality, audio quality is directly linked to how much sound information a format can store.

At the bottom again is VHS with its linear audio track. This format uses only 1/5 of the the tape for audio recording resulting in very little information being saved on tape.

The Sony Hi-8 format uses hi-fi stereo for audio recording. hi-fi stereo is recorded using depth multiplexing which records the audio signal deeper into the tape underneath the video signal. This allows the entire width of the tape to be used for the audio tracks resulting in over twice as much recorded information when compared to VHS.

GENERATION LOSS
Video tape evidence is often copied and distributed to 2nd and 3rd parties (lawyers, ect.). The quality of copies rarely matches that of the original. Do a copy of a copy and things get worse.

This is called generation loss. Part of the problem is noise, which pollutes the signal a little more with each generation of tape. The other factor is the inevitable los of detail that happens when copying. Generation loss isn't just limited to video, sound can get noisy and indistinct as well.

In general, the better the quality of the format, the less generation loss you'll notice with each copy. This is why VHS suffers the most from generation loss. This format often reveals considerable degradation after just one copy.

Sony Hi-8, because of its depth multiplexing, is far less susceptible to generation loss. And because Sony Hi-8 records more detail and less noise to begin with, the small amount of generation loss is far less noticeable.

Optical Zoom vs Digital Zoom
Optical Zoom: Allows you to capture close-ups without sacrificing resolution (picture quality). It uses the actual lens to magnify the image, whereas a digital zoom uses computer imaging to magnify the image. Although digital zooms can go much farther than optical, they sacrifice quality, as they are only computer approximations of the image, rather than the actual image. Optical Zoom produces the highest quality picture.

Digital Zoom: Integrated technology that lets you magnify a portion of an already captured image to achieve the effect of a zoom. This means that the existing data is not enhanced, but merely displayed at a lower resolution (picture quality). As the magnification or zoom increases the resolution decreases. When you zoom digitally, you are essentially just cropping part of the image, without increasing the resolution of the portion of the image you really want to keep.