(Parte 1 de 4)

Image sen sor f ormat

Fr o m Wikipedia, the free e ncycl o pedia

, search

C o mparative dime nsi o ns o f se ns o r sizes

I n digital photo graphy, the image se ns o r fo rmat is the shape a nd size o f the image se ns o

The image se ns o r fo rmat o f adigital camera determi nes thea ngle o f view o a particular le ns whe n used with a particular camera. I n particular,image se ns o rs in digital SLR cameras te nd to be smaller tha n the 24 m x 36 m image area o ffull-frame35 m cameras, a nd therefo re lead to a narr o wer

a ngle o f view.

Le nses pro duced fo r35 m filmcameras may mou nt well o n the digital b o dies, but the largerimage circle o f the 35 m system le ns allo u nwa nted light i nt o the camera bo dy, a nd the smaller size o f the image se ns o r co mpared to 35 m fo rmat results i n croppi ng o f the image c o mpared to the results pro duced o n the film camera. This latter effect is k n o w n as field-o f-view cro p; the fo rmat size ratio is know n as the field o ngth multiplier.

C o nte nts [hide] r size

2 Se ns o r size vs. le ns size a nd depth o f field rmats rmats rmat DSLR

3.3 Co mpact digital camera fo rmats r sizes

4 Bridgi ng the gap i n se ns o r sizes

5 See also 6 No tes a nd refere nces nks

[edit] Se ns o r size

All o ther thi ngs bei ng equal, a larger se ns o r captures images with greater 2

dy namic ra nge tha n a smaller se ns o r. The larger area pro vides a larger "well" i n whichphoto n -freed electr o ns ca n accumulate befo re o verfl o w (highlight ccurs.

M a nyDSLRs have se ns o r areas arou nd 370 mm2, while ma ny c o mpact camera se ns o rs have o ne-fiftee nth the surface area: a sta ndard 1/2.5" se ns o has a surface area o f 24.7 mm2. Thus, a typical DSLR will have a sig nal-t o - n o ise ratio that is nearly 4 times higher tha n a typical co mpact digital camera:

N o tice that no ise is reduced as reso luti o n is reduced, all o ther thi ngs bei equal. I n o ther wo rds, a 1/2.5" se ns o r that is 12 megapixels will have a lo wer sig nal to no ise ratio whe n co mpared with a n 8 megapixel camera with the same size se ns o

[edit] Se ns o r size vs. le ns size a nd depth o f field

A n impo rta nt side effect o f se ns o r size is le ns size.

Images fed to digital se ns o rs must be made up o f rays hitti

ph o t o recept o rs as clo se to perpe ndicular as po ssible. To pr o duce such images- the large o nes needed by large se ns o rs especially- bulky le nses are necessary. Large se ns o rs, besides, are very expe nsive (see DSLR/M f o rmats chapter, here belo w) a nd o nly make se nse whe n co upled to highly c o rrected, co mplex o ptics, by defi niti o n bou nd to be huge.

Film cameras did no t have such pro blems: film is cheap a nd it is se nsitive to light no matter its directio n. That is po ssibly the mai n reaso m (full-frame) co mpact-z o o m film cameras existed who se le nses(see here f o r a n example), were i nc o mparably smaller tha n a ny full-frame digital 3

z o o m le ns. Ano ther reaso n fo r this huge differe nce is that o ld-time full- frame co mpact-z o o m film-cameras were mea nt mai nly to pr o cm. pri nts. Digital sho ts, i nstead, e nd up bei ng viewed at high mag nificati o n o n large scree ns. So le nses feedi ng se ns o rs must do particularly go o d jo b, which co mes at a price. Bulk i ncluded.

Se ns o r size i nversely affects depth o f field (the larger the se ns o r, the shall o wer the d.o .f.). I n o ther wo rds, larger se ns o rs allo w a mo re marked

B o keh , a much so ught-after effect by pro fessi o nal photo graphers a ph o t o -e nthusiasts. As a co nseque nce, tho ugh, cameras usi ng large se ns o need a particularly accurate fo cusi ng (which, i n tur n, may tra nslate i nt o further bulk, system co sts a nd le ns quality issues).

[edit] Co m o n image se ns o r fo rmats 4

Sizes o f the se ns o rs used i n mo st curre nt digital cameras relative to sta ndard 35mm frame.

[edit] DSLR/M ILC fo rmats

S o me pro fessi o nal DSLRs use full-frame se ns o rs, equal to the size o f a

frame o f 35 m film. M o st co nsumer-level DSLRs a nd M

ILCs/EVILs use relatively large se ns o rs, either arou nd the size o f a frame o fAPS-C film, with acro p facto f 2.0 (this is the

F o ur Thirds System, ado pted byOlympus a nd Pa nas o

O n September 21st 2011, Niko n annou nced a new fo rmat, which they named CX[1]. It will be ado pted fo r the Niko n 1 camera system (Niko n J a nd V1 mo dels). The se ns o r size o f the CX fo rmat is 1" (2.7 cro p facto

As o f September 2011 there is o nly o ne M ILC mo del equipped with a very typical o f co mpact digital cameras. See Co mpact digital camera fo rmats secti o n belo

M a ny differe nt terms are used i n marketi ng a nd describi ng these se ns o f o rmats, i ncludi ng the fo l o wi

Full-frame digital SLR fo rmat, with se ns o r dime nsi o ns nearly equal to th o se o

Ca n o n 's APS-H fo rmat fo r high-speed pro -level DSLRs (cro p facto

APS-C refers to a ra nge o f similarly-sized fo rmats, i ncludi ntax, Ko nica Mino lta/S o nyα, Fuji (cro p facto

Ca n o n e ntry-level DSLR fo rmats (cro p facto

F o ve o n X3 fo rmat used in Sigma SD-series DSLRs (cro p facto

F o ur Thirds System fo rmat (cro p facto

Nik o n CX fo rmat used in Nik o n 1 series (cro p facto

Pr o ducti o n co sts fo r afull frame se ns o r ca n exceed twe nty times the co sts o a n APS-C se ns o r. O nly abo ut thirty full-frame se ns o rs ca n be pro duced o a n 8 i nches (20 cm) silico n wafer that wo uld fit 112 APS-C se ns o rs, a there is a sig nifica nt reductio n in yield due to the large area fo c o ntami na nts per co mpo ne nt. Additio nally, the full frame se ns o r requires three separate expo sures duri ng thephoto lith o graphy stage, which requires separate masks a nd quality co ntr o l steps. The APS-H size was selected si nce it is the largest that ca n be imaged with a si ngle mask to help co ntr o

pr o ducti o n co sts a nd ma nage yields.[2]

Due to the ever-cha ngi ng co nstrai nts o f semic o nduct o r fabricatio n a pr o cessi ng, a nd because camera ma nufacturers o fte n so urce se ns o rs fro

third-party f o u ndries, it is co m o n fo r se ns o r dime nsi o ns to vary slightly withi n the same no mi nal fo rmat. Fo r example, theNiko n D3 a cameras' no mi nally full-frame se ns o rs actually measure 36 × 23.9 m, slightly smaller tha n a frame o f 35 m film. As ano ther example, thePe ntax

K200D's se ns o r (made bySo ny) measures 23.5 × 15.7 m, while the c o ntempo ra ne o usK20D's se ns o r (made bySamsu

o st DSLR image se ns o r fo rmats appro ximate the 3:2aspect ratio o m film. Agai n, theFo ur Thirds System is a no table exceptio n, with an aspect ratio o f 4:3 as see n i n mo st co mpact digital cameras (see belo rmat DSLR

The mo st co m o n se ns o r size fo r medium-fo rmat digital cameras is the widespread

(Parte 1 de 4)