Implantable Radio Frequency Identification Tags
These devices are commonly known as RFID tags, and are most widely used in standard supermarket and library security systems. Ken Livingstone's faintly Orwellian Oyster cards, for paying Tube fares, are also individual RFID tags. The example pictured is particularly small - the size of a grain of rice - and could therefore be implanted under the skin of a human, in the same way that many household pets now carry ID chips. Once there, it can be used for identification, tracking or to store vital medical details such as blood group and allergies, or even used instead of a credit card.
Entomopter
A micro air vehicle (MAV) inspired by the movement of an insect, rather than a traditional aircraft. It can fly, crawl and swim, accessing areas that remote-controlled helicopters, for instance, cannot reach. Could be used in both emergency and espionage situations to enter a building (say through an open window). This example is about six inches long. The only thing preventing smaller versions being developed is the relatively large size of batteries. This machine uses a "reciprocating chemical muscle" that flaps the MAV's wings, and the waste gases from its fuel cell are recycled to power the flight controls and its on-board sonar sensor.
Keystroke Logger
This discrete device can be plugged into the back of any PC, and will then capture every keystroke typed in by the user. In the past, criminals and spies have used keystroke loggers to discover passwords and even invade online bank accounts. They are simple, effective and widely used, and can now be bought from any spy shop for around £50. Because they are hardware, rather than invasive items of software, normal anti-virus devices won't pick them up: the only way to tell they're there is to look at the back of your computer. Knowing these exist may make you think twice about using internet cafés...
Mobile phone security
The advent of mobile phones has been a gift to spies, who can pack a handset with hidden technology, from bug detectors to voice changers that disguise their identity. To be sure that the gadget does not fall into the wrong hands, they can also be fitted with iris scanners. Although expensive now, this could be the answer to gadget theft in the future. After all, colour screens were once expensive, too.
Spyrobot camera
The "tough-grip" wheels allow this mobile device to crawl into danger zones, run down stairs, and climb 40-degree slopes. It is self-righting, and can survive a 2m drop before being used to shoot either video or stills. This model is made by a firm called Macroswiss and can be bought over the counter for a few thousand pounds. It can be thrown through a glass window and used to film the inside of an unfamiliar building, and has all kinds of implications for fire brigades and rescue teams.
Super-powered Spy Leg
Finally, this is one possible example of technology that spies might use in 20 years, given current trends, a vision of the future from product designers at the Royal College of Art. It's a prototype of an artificial leg that would be stuck on in place of the agent's real limb to augment his (or her) physical skills. Four separate attachments can be used: a "cheetah" leg for fast running and high jumping, a tentacle appendage to help you climb like an octopus, a grapple hook for hanging (like Tom Cruise in Mission: Impossible) and a swanky brogue for undercover work. It's all a bit Inspector Gadget.
Source: http://www.belfasttelegraph.co.uk
One limitation of traditional cameras is the fact that they must be long in order to have an optical zoom, which is composed of several lenses that bend and focus light. Digital zoom is available for spy cameras and mobile phones, but such zoom makes the image blurry and with low contrast. 
