By : Nikon School Blog | 21 Feb, 2018 |
Nikon started their digital SLR line up with the DX format. A few years later, the FX format was launched. The CX format followed a few years after this. These terms denote the different sensor sizes used by three different categories of Nikon’s Digital cameras with inter-changeable lenses. If you own any of these Nikon cameras, it will help to understand the fundamental differences between these three sensor sizes and how they affect the images you shoot.
Before SLRs became digital, the 35mm film was considered a standard medium for photography around the world. However, the first Nikon DSLRs used a sensor with an image area smaller than that of the 35mm film. Nikon called this sensor the DX format which measures approx. 23.5 mm x 15.6 mm. A new line of lenses optimised to create images on this smaller sensor was developed and designated as the Nikon DX format line-up. The DX logo is still visible on all lenses of this line-up. The DX format is about 1.5 times smaller than the 35mm film format and hence said to have a crop factor of 1.5 times. All DX format lenses have an effective focal length of 1.5 times their physical focal lengths.
Next to join the Nikon DSLR line up were the FX format DSLRs. These used an image sensor approximately the same size as the 35mm film (35.9 mm x 23.9 mm). A new line up of lenses was introduced to form images for the FX sensor, though they were not officially called ‘FX’ lenses. The cameras with the FX format sensor got the FX logo imprinted instead. The FX format being the same size as the 35mm format, there is no crop factor involved and lens focal lengths are what they are physically.
With the launch of the Nikon 1 series of interchangeable lens cameras, the CX format was introduced. This sensor strives to create a perfect balance between high image quality and compact form factor. The CX format is the smallest of the three, measuring 13.2mm x 8.8mm. This sensor has a crop factor of 2.7 times. The 1 NIKKOR lens line up was launched to make images with the CX format cameras.
All the three lens line ups offer lenses with different focal lengths but similar fields of view. For example, the standard ‘normal’ lens with the FX format is the 50mm which offers a picture angle of 47 degrees. This corresponds to the 35mm in the DX format which offers a picture angle of 44 degrees on the DX format. For CX format cameras, the 18.5mm acts as the ‘normal’ lens. It offers a picture angle of approx. 46 degrees.
However, though these lenses offer similar picture angles, they will differ slightly in the depth-of-field they offer. The higher focal length lens will result in shallower depth-of-field, and the smaller focal length more depth of field at same apertures.
While shooting with these formats, it’s useful to keep these factors in mind. The three different Nikon sensor formats each have their own usefulness. In the end, they all offer the same thing to their users – the happiness and satisfaction of creating beautiful images.