There are no current digital cameras with interchangeable lenses, but there is a lot of talk about EVIL, or Electronic Viewfinders Interchangeable Lens, cameras. This has already been initiated in several of the bridge cameras.
The only thing that remains is combining the technology with lens interchangeability; the challenge is not so much technology as it is marketability. Interchangeable lenses are available on the high end of digital rangefinders, but are too high end to be considered bridge cameras.
Because of the small sensor on bridge cameras, the smaller diameter lens is quite sufficient; this makes very large zoom ranges possible with a single lens. Focal lengths equal to 436 mm on a 35mm camera are feasible in a compact body with a fixed zoom or ultra zoom lens.
Lens interchangeability is rendered nearly unnecessary when a single small-diameter zoom lens can take the place of a wide-angle, telephoto, and macro lens. This has caused manufacturers to make all small-sensored bridge cameras with a fixed lens.
There are two general types of electronic screens used as viewfinders in the bridge cameras and LPD -- the LCD or the Electronic Viewfinder or EVF. A high-quality Electronic Viewfinder distinguishes the more advanced bridge camera from the consumer-compact LPD cameras.
In LPDs, there is no mirror blocking the image created by the lens projecting over the sensor as in the dSLRs; the image is continuously generated by the sensor. This is one of the main characteristics of LPDs, and there are both advantages and disadvantages over the view that is optically generated by the dSLRs.
The digital preview is affected by all of the settings; this is an advantage because the image is seen as it will be recorded. The movable framing is another advantage, as framing can be done from different angles by moving the LCD viewer.
In situations of low light, the electronic screens do not work as well; this is a definite disadvantage. In addition, the screen has low resolution, making it more difficult to focus manually.