Wikipedia: A monopod, also called a unipod, is a single staff or pole used to help support cameras, video cameras, binoculars, rifles or other precision instruments in the field.
Quick Benefits:
- Lightweight, especially compared to a tripod.
- Smaller, more easy to transport.
- Adds around 1-3 f-stops.
- Eliminates vertical vibrations.
- Quicker to set up than a tripod.
- No longer hand holding heavy lenses.
Downside:
- Obviously not as stable as a tripod.
- Vertical shots are hard to take, unless you have an L clamp on your camera.
Overall:
Like most camera equipment, monopods have a specific place in the photography market. They are primarily used by sports photographers who need the flexibility to quickly move about their event without lugging larger, heavier tripods. Monopods work great not only steadying your camera, but also when carrying your camera. Simply swing your camera over your shoulder with the lens running down your back.
Hikers prefer monopods due to their light weight construction, and the ability to fold them to such a small and compact size.
If you are absolutely in love with your monopod and wish for the “fine tuning” that a tripod can achieve, throw on a ball head! Usually you won’t find any sort of head on a monopod, but you can now keep the monopod perfectly vertical and still rotate your camera. This will increase the stability overall.
Lastly, ignore monopods with “mini” tripods legs on the bottom. They’re so small they really don’t increase the stability, and only reduce the weight and size benefits of a monopod.
I highly recommend checking out this site for technique suggestions, it will increase the stability while holding onto the monopod.