the square root of sensor area (to within a small aspect ratio-dependent factor), it is useful for estimating image sensor performance. For example, if two different-sized image sensors have the same aspect ratio and a resolution of 10 megapixels, and are made using similar technology, the larger sensor will have better signal-to-noise ratio by a factor equal to the ratio of the two sensors' crop factors. The larger sensor has the smaller crop factor and the higher signal-to-noise ratio. Digital lenses Most SLR camera and lens manufacturers have addressed the concerns of wide-angle lens users by designing lenses with shorter focal lengths, optimized for the DSLR formats. In most cases, these lenses are designed to cast a smaller image circle that would not cover a 24×36 mm frame, but is large enough to cover the smaller 16×24 mm (or smaller) sensor in most DSLRs. Because they cast a smaller image circle, the lenses can be optimized to use less glass and are sometimes physically smaller and lighter than those designed for full-frame cameras. Lenses designed for the smaller digital formats include Canon EF-S and EF-M lenses, Nikon DX lenses, Olympus Four Thirds System lenses, Sigma DC lenses, Tamron Di-II lenses, Pentax DA lenses, Fujifilm XF and XC lenses, and Sony Alpha (SAL) DT & E lenses. Such lenses usually project a smaller image circle than lenses that were designed for the full-frame 35 mm format. Nevertheless, the crop factor or FLM of a camera has the same effect on the relationship between field of view and focal length with these lenses as with any other lens, even though the projected image is not as severely "cropped". In this sense, the term crop factor sometimes has confusing implications; the alternative term "focal length multiplier" is sometimes used for this reason. Crop factor of point-and-shoot cameras Smaller, non-DSLR, consumer cameras, typically referred to as point-and-shoot cameras, can also be characterized as having a crop factor or FLM relative to 35 mm format, even though they do not use interchangeable lenses or lenses designed for a different format. For example, the so-called "1/1.8-inch" format with a 9 mm sensor diagonal has a crop factor of almost 5 relative to the 43.3 mm diagonal of 35 mm film. Therefore, these cameras are equipped with lenses that are about one-fifth of the focal lengths that would be typical on a 35 mm point-and-shoot film camera.