MEGA PIX­ELS MEGAP ARE NOT IXELS

HWM (Malaysia) - - LAB TEST -

Im­age sen­sors have lim­i­ta­tions. Two sen­sors of difer­ent sizes, a larger one in a DSLR and a smaller one in a smart­phone, can have the same num­ber of me­gapix­els, i.e. the same num­ber of pix­els on their sen­sors, but the larger sen­sor in the DSLR will pro­duce a bet­ter im­age.

That’s be­cause the smaller sen­sor crams more pho­to­sites onto a smaller sur­face area, thus each pho­to­site is smaller and its abil­ity to cap­ture light is less­ened. It’s like two peo­ple who each have the same num­ber of buck­ets to col­lect rain wa­ter, only one has larger buck­ets and the other has smaller ones.

Gen­er­ally speak­ing, larger sen­sors with larger pho­to­sites pro­duce bet­ter look­ing im­ages. This is not al­ways true, but all things be­ing equal, a larger sen­sor can cap­ture an im­age with more clar­ity, a higher dy­namic range, more ac­cu­rate color and with less im­age noise. So while it looks like you should just have more me­gapix­els on big­ger sen­sors, the re­al­ity is that it’s more of a ne bal­anc­ing act than a sim­ple com­bi­na­tion.

But pho­to­site size is just one part of the pic­ture the num­ber of pix­els is an­other. ith fewer pix­els you sac­rice im­age de­tail - there are less pix­els to ‘draw’ the same amount of in­for­ma­tion as a sim­i­larly-sized sen­sor with more pix­els. Re­mem­ber that a dig­i­tal im­age is com­posed of in­di­vid­ual dots, or pix­els. The more there are, the ner your im­ages can be. A rough ex­am­ple would be the be­tween the -bit NES graph­ics of yes­ter­day, and to­day’s ful­lHD PlaySta­tion 3 games.

The sen­sors in mo­bile phones face a dou­ble chal­lenge, they aren’t as big as the sen­sors found in dig­i­tal cam­eras, so they

have to com­pen­sate with more me­gapix­els to ‘draw’ more de­tail. But if they cram too many me­gapix­els in a small sen­sor, they face the risk of de­grad­ing the nal im­age qual­ity.

Fur­ther, while sen­sor size and pixel count are re­li­able in­di­ca­tors of im­age qual­ity, they don’t form the en­tire pic­ture. Im­prove­ments in im­age qual­ity can be made from ad­vances to sen­sor tech­nol­ogy and im­age pro­cess­ing as well.

The more pix­els you have, the finer the de­tail you can cap­ture in an im­age.

Imag­ine that each red block rep­re­sents 1 mil­lion pix­els. Even though th­ese two sen­sors have the same num­ber of pix­els, the pix­els or pho­to­sites on the larger sen­sor are big­ger. This is why, even though a DSLR cam­era and a smart­phone can both shoot at 12MP, the im­ages from the DSLR cam­era’s larger sen­sor will look bet­ter.

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