The size of the image sensor can affect the effective focal length of a lens. A larger sensor will capture a wider field of view and result in a shorter effective focal length, while a smaller sensor will capture a narrower field of view and result in a longer effective focal length.

Focal length can be calculated by dividing the distance from the lens to the image sensor (or film) by the distance from the lens to the subject. This is known as the thin lens equation: 1/f = 1/di + 1/do, where f is the focal length, di is the distance from the lens to the image sensor, and do is the distance from the lens to the subject.

LONDON - Utarget, the online ad network, has merged its sales and publisher services with Fox Networks, the UK sales and ad network of Fox International Channels (FIC), its majority stake owner.

The focal length of a lens is a fixed characteristic and cannot be changed. However, the field of view and magnification can be altered by using different lenses or adjusting the distance between the lens and the image sensor.

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The focal length of a lens is directly related to its magnification power. A shorter focal length results in a wider field of view and less magnification, while a longer focal length results in a narrower field of view and greater magnification.

FIC acquired a majority stake in the UK-based online ad network Utarget in 2008 for an undisclosed sum.The merging of commercial operations means Utarget's 18-strong team, based in Windsor and headed by chief executive and founder Phil Cooper, has moved to the Shepherd's Bush offices of Fox Networks, the seven-strong online advertising network.Cooper said the move was not down to cost-cutting and has not led to any redundancies, but would prompt a number of benefits, including the sharing of resources, such as product offering, publisher networks and economies of scale.As part of the change, Cooper will continue in his role with  added responsibility of the overall Fox operations in the UK. Federica Aperio, UK managing director, will add oversight of sales, publisher services and ad operations for all products.The merger was announced by Hernan Lopez, chief operations officers of FIC, who said the move would mean the combined entity was in a "better position to serve advertiser and agency needs in the UK".

Focal length is a measurement of the distance between the center of a lens and the point where light rays converge to form a clear image. It is typically measured in millimeters (mm) and is an important factor in determining the magnification and field of view of a lens.