Christmas lights in the context of "Christmas decoration"

In optics, defocus is the aberration in which an image is simply out of focus. This aberration is familiar to anyone who has used a camera, videocamera, microscope, telescope, or binoculars. Optically, defocus refers to a translation of the focus along the optical axis away from the detection surface. In general, defocus reduces the sharpness and contrast of the image. What should be sharp, high-contrast edges in a scene become gradual transitions. Fine detail in the scene is blurred or even becomes invisible. Nearly all image-forming optical devices incorporate some form of focus adjustment to minimize defocus and maximize image quality.

The Christmas season or the festive season, also known as the holiday season or the holidays, is an annual period generally spanning from November or December to early January incorporating Christmas Day and New Year's Day. The gift-giving associated with the season creates a peak season for the retail sector extending to the end of the period ("January sales"). Christmas window displays and Christmas tree lighting ceremonies are customary traditions in various locales.

In Western Christianity, the Christmas season is traditionally synonymous with Christmastide, which runs from December 25 (Christmas Day) to January 5 (Twelfth Night or Epiphany Eve), popularly known as the 12 Days of Christmas. Christmas in Italy is one of the country's major holidays and begins on 8 December, with the Feast of the Immaculate Conception, the day on which traditionally the Christmas tree is mounted and ends on 6 January, of the following year with the Epiphany. As the economic impact involving the anticipatory lead-up to Christmas Day grew in America and Europe into the 19th and 20th centuries, the term "Christmas season" began to also encompass the liturgical Advent season, the period of preparation observed in Western Christianity from the fourth Sunday before Christmas Day until the night of Christmas Eve. The term "Advent calendar" continues to be widely known in Western parlance as a term referring to a countdown to Christmas Day from the beginning of December.

A Christmas tree is a decorated tree, usually an evergreen conifer such as a spruce, pine or fir, associated with the celebration of Christmas. It may also be an artificial tree of similar appearance.

The custom was developed in Central Europe, particularly Germany and Livonia (now Estonia and Latvia), where Protestant Christians brought decorated trees into their homes. The tree was traditionally decorated with "roses made of colored paper, tinsel, apples, wafers, and confectionery". Moravian Christians began to illuminate Christmas trees with candles, which were often replaced by Christmas lights after the advent of electrification. Today, there is a wide variety of Christmas ornaments, such as garlands, baubles, tinsel, and candy canes. An angel or star might be placed at the top of the tree to represent the angel Gabriel or the Star of Bethlehem, respectively, from the Nativity. Edible items such as gingerbread, chocolate, and other sweets are also popular and are tied to or hung from the tree's branches with ribbons. The Christmas tree originated as a custom of the Lutheran Churches and only in 1982 did the Catholic Church erect the first Vatican Christmas Tree.

The economics of Christmas are significant because Christmas is typically a high-volume selling season for goods suppliers around the world. Sales increase dramatically as people purchase gifts, decorations, and supplies to celebrate. In the U.S., the "Christmas shopping season" starts as early as October. In Canada, merchants begin advertising campaigns just before Halloween (31 October), and step up their marketing following Remembrance Day on 11 November. In the UK and Ireland, the Christmas shopping season starts from mid-November, around the time when high street Christmas lights are turned on. In the United States, it has been calculated that about one fifth of retail sales to one quarter of all personal spending takes place during the Christmas/holiday shopping season. Figures from the United States Census Bureau reveal that expenditure in department stores nationwide rose from $20.8 billion in November 2004 to $31.9 billion in December 2004, an increase of 54 percent. In other sectors, the pre-Christmas increase in spending was even greater, due to a November through December buying surge of 100% in bookstores and 170% in jewelry stores. In the same year employment in American retail stores rose from 1.6 million to 1.8 million in the two months leading up to Christmas. This means that while consumers might spend more during this season, they also are given increased employment opportunities as sales rise to meet the increased demand.

Industries completely dependent on Christmas include Christmas cards, of which 1.9 billion are sent in the United States each year, and live Christmas trees, of which 20.8 million were cut in the U.S. in 2002. In most Western nations, Christmas Day is the least active day of the year for business and commerce; almost all retail, commercial and institutional businesses are closed, and almost all industries cease activity (more than any other day of the year), whether laws require such or not. In England and Wales, the Christmas Day (Trading) Act 2004 prevents all large shops from trading on Christmas Day. Film studios release many high-budget movies during the holiday season, including Christmas films, fantasy movies or high-tone dramas with high production values to hopes of maximizing the chance of nominations for the Academy Awards.

Christmas in Italy (Italian: Natale, pronounced [naˈtaːle]) begins on 8 December, with the Feast of the Immaculate Conception, the day on which traditionally the Christmas tree is mounted and ends on 6 January, of the following year with the Epiphany (Italian: Epifania [epifaˈniːa]), and in some areas female puppets are burned on a pyre (called falò), to symbolize, along with the end of the Christmas period, the death of the old year and the beginning of a new one. 26 December (Saint Stephen's Day, in Italian Giorno di Santo Stefano), is also a public holiday in Italy. The Italian term Natale derives from the Latin natalis, which literally means 'birth', and the greetings in Italian are buon Natale (Merry Christmas) and felice Natale (lit. 'happy Christmas').

The tradition of the nativity scene comes from Italy. One of the earliest representation in art of the nativity was found in the early Christian Roman catacomb of Saint Valentine. The first seasonal nativity scene, which seems to have been a dramatic rather than sculptural rendition, is attributed to Saint Francis of Assisi (died 1226). Francis' 1223 nativity scene in Greccio is commemorated on the calendars of the Catholic, Lutheran and Anglican liturgical calendars, and its creation is described by Saint Bonaventure in his Life of Saint Francis of Assisi c. 1260. Nativity scenes were popularised by Saint Francis of Assisi from 1223, quickly spreading across Europe. It seems that the first Christmas tree in Italy was erected at the Quirinal Palace at the behest of Queen Margherita, towards the end of the 19th century. Mount Ingino Christmas Tree in Gubbio is the tallest Christmas tree in the world. In Italy, the oldest Christmas market is considered to be that of Bologna, held for the first time in the 18th century and linked to the feast of Saint Lucy. Typical bearers of gifts from the Christmas period in Italy are Saint Lucy (December 13), Christ Child, Babbo Natale (the name given to Santa Claus), and, on Epiphany, the Befana.