Digital photography is an ocean of acronyms, names and numbers. It is very easy to sink in this ocean if you don’t know how to swim, or at least how to wear a life jacket. The chances are if you are just starting off as a photographer, you may have already been pestered with terms such as full frame, crop, 4/3rd and so on sensor sizes. The sensor size and its features are probably the most heard and talked about aspect of a digital camera. You are certainly going to be hearing more about these as you progress further in your journey. There are already oodles of information about them on the Internet and some of them are really so technical that it takes the fun out of something which was originally supposed to be pure enjoyment. It will remain a priority to use as less acronyms as possible in this brief study of sensor sizes to ensure that you are not further pestered with acronyms.
Let’s just take one size at a time and understand a bit more about it. First up is the full frame sensor. But before we can delve into that, let’s just say a few quick words about what the sensor is and why it is so important. If there would have been no sensors, then it would be like, well, shooting pictures with your old film camera except without any film! The sensor is to a digital camera what the film it to a film camera. It is where the images projected through the lens gets transposed and then captured. Basic thumbrule of photography is larger the sensor size, the more light it can capture and thus better the images.
Full frame cameras are those digital cameras which uses a sensor size roughly equivalent to that of the size of a 35mm film. In precise measurements, if I am allowed to use at least dimensional measurements, it is 24mm by 36mm. Large sensors are also more expensive to build and as such you can only find them in the professional or upper semi-professional bodies. One very popular camera using the full frame sensor is the Canon 5D Mark III. The newly launched and highly acclaimed Nikon D800 also uses a full frame sensor.
Cropped sensor is a term used to denote a sensor that has a size which is smaller than full frame. All sensors smaller than full frame are considered as cropped sensors. However there are several different sizes and each one has a unique name associated with it. A cropped sensor is less expensive to make and as such most of the current DSLR camera makers have several cameras with cropped sensors and compatible lenses in their product range. However there is a distinct disadvantage when it comes to shooting images in low light for cropped sensors. As full frame sensors are larger, they have a distinctly better low light performance as they can collect more light compared to their smaller brethren.
Micro 4/3rd system was designed by Olympus and Panasonic. However unlike the 4/3rd system this is not an open system. This system is widely used in their mirrorless interchangeable lens cameras which are smaller when compared to the DSLRs with an APS-C sensor. Smaller size comes from the fact that these cameras don’t have a mirror to project the image to the optical viewfinder. Needless to say that there are no optical viewfinders either.