Freeman on… Sensor Size
This issue, Nikon guru Michael Freeman explores what sensor size means, and why it’s important
of field than a DX sensor at the same aperture selective-focus shots when you want to blur out the background (with DX sensors the background will be blurred at wide apertures, just not as much – see page 77).
All this, however, comes at a price, both in terms of literal financial cost (since FX cameras and lenses are more expensive than their DX equivalents) and in terms of size and weight: if you shoot DX, you’ll save money and your kit will be smaller, lighter and generally more compact and convenient to handle, plus you’ll benefit from one notable advantage: the same focal length on a telephoto lens will give you half as much magnification again (so, for example, a 200mm lens will give you an effective focal length of a 300mm lens on a DX body). The FX sensor format maintains the dimensions of traditional 35mm film, while the DX sensor format, which is two-thirds smaller in terms of width and height, covers less than half the area (about 43 per cent). Here you can see how this affects the amount of a scene that you can get within the frame at identical focal lengths – which is why you’ll often see us referring to the ‘crop factor’ of DX cameras in lens reviews.