Digital Sensor Sizes
Sometimes it is a good idea to reiterate something. Multiple web sites contain information about relative digital camera sensor sizes, but it won’t hurt to have another source of information, so here goes…
The illustration shown here is rough. Don’t count the pixels because the scale is not dead on, and the sensors sizes are not at 100%. This merely shows the relative sizes of common sensors.
Note that there are many sensor sizes used in compact point-and-shoot digitals. All relatively small. The Four Thirds sensor is the same size used by the Micro Four Thirds system. The Micro Four Thirds system doesn’t use a mirror and pentaprism, so the camera bodies are smaller than Four Thirds cameras.
The controversial Foevon sensor used by Sigma in its digital cameras is a source of (enthusiastic) argument among photography enthusiasts due to the way Sigma counts pixels. For more information on the Foevon sensor, just run a web search on Foevon Sensor, then sit back for the first forty to fifty hours of reading.
Also note Canon’s slightly smaller APS-C sensor. It explains Canon’s slightly larger crop factor with 35mm lenses. The Nikon APS-C size is shared by Pentax and Sony DSLRs.