Compact is ISO 400, whereas the digital SLR has an ISO of 1600. Six years on the market equivalent for the digital compact camera would be something like the Sony Cyber Shot HX 100V³ but at a price point closer to £300 rather than £700. For this you get a 16.2-megapixel camera with thirty times optical zoom and an ISO sensitivity of between 100 and 3200. The camera has an inbuilt GPS receiver SO that pictures can be geotagged. There is a 2D and 3D sweep panorama facility with autostitching. Still images can be captured at a rate of ten per second. Video can be captured at 30 frames per second at 1920 by 1080 (2 megapixel) resolution that equates to a data capture rate of 17 Mbps. A high-end digital SLR such as the DSLR 850 from Sony, albeit at a slightly higher price (of the order of £1800) has an ISO rating of 100 to 6400 and a resolution of 24.6 megapixels. Bear in mind that at this kind of resolution a single JPEG image can easily be 20 MB or closer to 40 Mb as an uncompressed RAW file. If you want to absorb memory bandwidth this is a good way to do it. Comparing compacts with SLRs at equivalent prices just on the basis of resolution may suggest that the compacts offer better value for money. However, compact cameras have smaller sensors, which means the pixels are smaller which means they collect fewer photons, which means they are less sensitive and have a lower signal-to-noise ratio. The smaller the sensor, the more the magnification needed to produce a same size print. Smaller sensors also will tend to exhibit more severe chromatic aberration and sensor blooming (where a charge leaks from an overloaded pixel to its neighbours). The lens on a compact gives a longer focal length than the standard lens of the SLR, though the motor drivers can be quite slow. Compacts and SLRs both typically have a wide aperture range. A wider aperture will deliver more photons to the sensor array but will reduce the depth of field (the range over which differ- ent parts of the captured image remain in focus). Other differences