untitled

Oman (ⁱ/oʊˈmɑːn/ oh-maan; Arabic: عمان‎ ʻUmān), officially called the Sultanate of Oman (Arabic: سلطنة عُمان‎ Salṭanat ʻUmān), is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates (UAE) to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the southeast and the Gulf of Oman on the northeast. The Madha and Musandam enclaves are surrounded by the UAE on their land borders, with the Strait of Hormuz and Gulf of Oman forming Musandam's coastal boundaries.

A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than 400 millimetres (16 in). A common definition distinguishes between true deserts, which receive less than 250 millimetres (10 in) of average annual precipitation, and semideserts or steppes, which receive between 250 millimetres (10 in) and 400 to 500 millimetres (16 to 20 in).

Deserts can also be described as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system, deserts would be classified as arid megathermal climates.

In optics, particularly as it relates to film and photography, depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Although a lens can precisely focus at only one distance at a time, the decrease in sharpness is gradual on each side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions.

In some cases, it may be desirable to have the entire image sharp, and a large DOF is appropriate. In other cases, a small DOF may be more effective, emphasizing the subject while de-emphasizing the foreground and background. In cinematography, a large DOF is often called deep focus, and a small DOF is often called shallow focus.

The DOF is determined by the camera-to-subject distance, the lens focal length, the lens f-number, and the format size or circle of confusion criterion.

For a given format size, at moderate subject distances, DOF is approximately determined by the subject magnification and the lens f-number. For a given f-number, increasing the magnification, either by moving closer to the subject or using a lens of greater focal length, decreases the DOF; decreasing magnification increases DOF. For a given subject magnification, increasing the f-number (decreasing the aperture diameter) increases the DOF; decreasing f-number decreases DOF.