WHAT IS A MEGAPIXEL?

HWM (Malaysia) - - LAB TEST -

First, let’s look at what a megapixel ac­tu­ally is. Ev­ery im­age you see on a dig­i­tal pho­to­graph is made up of tiny dots, each one called a pixel. A megapixel is a term for one mil­lion of th­ese pix­els, and megapixel is used to de­scribe the res­o­lu­tion of a dig­i­tal im­age, as well as the res­o­lu­tion of a dig­i­tal im­age sen­sor.

For ex­am­ple, when a JPEG im­age has a res­o­lu­tion of 4000 x 3000, it means that the im­age is made up of 4000 col­umns by 3000 rows of pix­els. It has a to­tal of 12,000,000 (4000 x 3000) pix­els, and since that’s a rather large num­ber to say, we shorten it by de­scrib­ing it as a 12MP (12,000,000 di­vided by a mil­lion) pic­ture.

Megapixel is also used to de­scribe the to­tal num­ber of pix­els on an im­age sen­sor. To cre­ate a 12MP im­age, an im­age sen­sor has at least 12 mil­lion pix­els, or pho­to­sites, on it. Each photo site cap­tures light as it passes through the cam­era’s lens and hits the sen­sor, and trans­lates that into dig­i­tal in­for­ma­tion which is ren­dered into

an im­age by the cam­era’s im­age pro­ces­sor.

The to­tal num­ber of ec­tive pix­els is difer­ent from the to­tal num­ber of pix­els on a sen­sor. An im­age sen­sor can’t use ev­ery pixel on it for the sim­ple rea­son that a sen­sor is rec­tan­gu­lar and lenses are round. So there are al­ways pix­els fall­ing out­side of the lens’ cov­er­age, and the e ec­tive pix­els are the ac­tual num­ber of pix­els which re­main to cap­ture the light.

Ev­ery dig­i­tal photo is made up of lit­tle pix­els.

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