Nhiep anh.docx

8/10/2019 Nhiep anh.docx

1/41

Nhip nh nng cao - C bn v DSLR Mt my nh thay ng knh, d c hay khng c gng lt, thngkh kh s dng vi nhng ngi mi bt u do n c qu nhiu ntv nhiu chc nng chnh.

Chun b Thi t b: Bt k my nh thay ng knh no. Mc tiu: Nm vng c nhng phn c bn ca mt my nhthay ng knh v cch cm my khi chp nh. Thi gian: 10 pht.

Mt khi hiu nhng khi nim c bn, ngi chp s thy cc nt chc nng trn DSLR c btr kh khoa hc v d hiu.

Bi di y s trnh by nhng g c bn nht thng c trn mt my nh thay ng knh. D v c bn l ging nhau, nhng ngi c cng cn lu l nhng my khc nhau, cc nt c th c btr nhng v tr khc bit.

Mt trc

Nhng nt ch mt trc my nh. nh: Cnet.

mt trc ca my nh, bn s thy iu u tin p vo mt l vng lp ng knh. y l ni bn phi lp ng knh trc khi c th chp c nh. Lu , cc my nh khc nhau s c ngm ng knhkhc nhau v ng knh dnh cho my nh no ch c th lp trn my nh . Thng thng, trn ngknh s c cc im trn c thn my v ng knh gip ngi dng xc nh c khp lp utin.


2/41

Nt tho ng knh thng b tr ngay cnh vin ng trn thn my. Khi lp ng knh v xoay, bn snghe mt ting "tch" bo hiu ng knh khp vo thn. Khi tho ng, ch vic bm nt tho vxoay ng ngc chiu vi chiu va lp vo.

Nt xem trc su trng nh (DOF preview) kh thng dng trn cc my nh DSLR trong khi

li thiu vng nhng my nh khng gng lt. Khi bm nt ny, my nh s khp m v ngthng s t gip ngi chp xc nh trc su trng nh ca bc nh s chp.

n h tr ly nt s t ng chiu sng ln i tng trong iu kin nh sng ti gip cm binnt ca my nh bt nt c tt hn. Tuy nhin, nu khng mun nh hng ti i tng chp, nny c th tt trong menu.

Mt trn

Cc ch mt trn. nh: Cnet.

Vng xoay ch trn mt trn gip ngi chp chuyn i gia cc ch chp. Cc ch thng

dng nht c t trn vng xoay ny l ch t ng, u tin ca trp, u tin m v chnh tayhon ton (thng k hiu tng ng bng cc ch ci P, A, S, M hoc P, Av, Tv, M).

Bn cnh vng xoay ch l nt chp nh. Chc nng ca nt chp ny chc chn qu r rng vtng t nh trn my nh du lch: dng ly nt v chp.

Khe cm n dng gn n flash ngoi. Mt s nh sn xut hin cn lm thm mt s ph kin cth lp trn khe ny nh thc cn bng chng hn.

Hu ht cc my thay ng knh s cp u c sn n flash tch hp. n ny c bt bng mt nt ngay cnh n mt trn ca my nh vi biu tng tia chp.

Mt sau


3/41

Mt sau my nh. nh: Cnet.

Chim phn ln mt sau l mn LCD v mt s nt chc nng khc. Cc nt ny thng thng baogm cc nt iu hng, xem li nh, nt xa nh. trn, mt s my i mi hn c th c thm ntxem sng Live View hoc nt quay video.

Pha trn mn LCD l khung ngm quang cn hnh chp nh. nhng my khng gng lt hocmt s DSLR i mi c chc nng LiveView, ngi chp c th cn khung bng mn LCD thay vkhung ngm quang.

Nt xem li nh thng c k hiu bng hnh tam gic quay sang phi, gip xem li nhng bc nhva chp. Nt Menu dng truy cp vo cc tnh nng su hn ca my nh hoc hiu chnhnhng thng s khc nh phn gii hoc cc tnh nng khc.

Nt iu hng hoc vng xoay iu hng gip duyt gia cc tnh nng khc nhau ca menu vcng l nt duyt xem cc nh chp. Thng thng, cc nt ny cn c thm chc nng l cc"phm nng" truy cp nhanh cc ty chnh thng dng nh ISO, ly nt hay cn bng trng.

Mt di v cnh bn


4/41

Cc cng giao tip v khe cm pin. nh: Cnet.

Mt di y ca my l khe cm pin. mt s phin bn, nh sn xut c th tch hp thm khe cmth. Nu khe cm th khng trong khe cm pin th thng c b tr bn sn my nh. Snmy nh cn l ni c cc cng USB, cng A/V hoc thm ch cng mini-HDMI trn mt s phin bn i mi.

Cch cm my ng

Cch cm my ng bn tri. nh: Cnet.


5/41

Khng ging nh my nh du lch, my nh thay ng knh nu khng cm ng cch c th khin nh b rung hoc gim sc nt ca nh. Cch cm tiu chun l tay cm chnh lun nm vng phn nhra ca my nh, trong khi tay cn li di ng knh.

Nhip nh nng cao - ng knh v cc thng s

Do kh nng thay th c ng knh nn ngi chp bng my DSLR c th la chn cc ng khcnhau cho nhng hon cnh khc nhau. > Nhip nh nng cao - C bn v DSLR

Chu n b - Thi t b: B t k my nh thay ng knh no - Mc tiu: Nm vng cch c cc thng s trn ng knh, khi no nn dng ng no v ccch c bn trn my nh. - Thi gian: 15 pht

Khng ging nh my nh du lch, my nh thay ng knh, ng nh tn ca n, phi c thm ngknh lp vo mi c th chp nh c. Do kh nng thay th c ng knh nn ngi chp c thla chn cc ng khc nhau cho nhng hon cnh khc nhau. bi ny, ngi c s tm hiu nhng phn c bn ca mt ng knh, cc loi ng knh v khi no th nn dng loi no.

Lu , v c bn d c tng t nhau nhng my nh khc nhau s c mt s khc bit v cch b trcng nh cch thc hot ng ca cc phm chc nng. V vy, ngi c vn cn tham kho schhng dn ca my nh ca mnh trc khi thc hnh chp.

Cc phn ca ng knh Mt trc.

Mt trc ng knh. nh: Cnet.
http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/http://sohoa.vnexpress.net/sh/camera/kien-thuc-nhiep-anh/2011/10/3b9b4ecf/


6/41

Mt trc ca ng knh thng c cc thng s biu th di tiu c v m ca ng knh .

Mt bn.

Mt bn ca ng knh. nh: Cnet.

mt bn, bn s thy vng zoom (nu l ng zoom) v vng xoay ly nt. Xoay vng zoom s iuchnh tiu c ca ng knh v xoay vng ly nt s iu chnh khong cch n i tng ly nt.Mt s ng knh i c cn c thm vng m iu chnh m trn ng knh. Tiu c ca ngknh cng thng c sn ln mt bn, nht l vi cc ng zoom.

Mt sau.


7/41


8/41

ng knh gc rng. nh: Wikia.

ng nh tn gi, ng gc rng cho mt gc nhn ln hn so vi gc tiu chun ca mt ngi. ngny thng c dng chp nh phong cnh c th thu c nhiu cnh vt hn. ng gc rngc th l ng zoom hoc prime, biu th bng s v n v mm, theo , s cng nh ng knh gccng rng (chng hn ng 28mm, 24mm hay 16mm).

ng zoom tiu chun.


9/41

My Canon 50D vi ng knh zoom tiu chu n. nh: Salestore.

Nu nh ng tiu chun cp n gc nhn tiu chun ca mt ngi th ng zoom tiu chunthng c hiu l ng kit i km my. Hu ht cc my thay ng knh s cp u i km ng kit ngi dng c th chp c ngay. Chng thng c di tiu c thng dng nht ko di t gc rngti tele v thng di khong t 28mm n 90mm.

ng tele.


10/41

ng tele ca Canon. nh: Letsgodigital.

ng tele gip thu i tng li gn hn. N c bit hu dng trong nhng tnh hung khng th vogn c ch th c chp, chng hn chp ng vt hoang d nh s t hay bo, hay i khi ch lchim mung. ng tele thng c di tiu c t 90mm tr ln v cng theo nguyn tc s cng ln tiu

c cng di (nh cc ng 300mm, 400mm hay 600mm). ng c chng.

ng knh Tilt-Shift. nh: The-picture.

Cc ng c chng thng ch hu dng mt s trng hp nht nh, chng hn nh ng macro,mt c hay ng trt (Tilt-Shift).

Thng s nhn hnh (crop) l g?


11/41

nh miu t h s crop trn my DSLR. nh: Cnet.

Khi mua my nh thay ng knh, c th bn s nghe thy thut ng "nhn hnh" (crop factor). Thutng ny bt ngun t vic kch c mi kiu phim trn my nh c trc y l 24 x 36 mm. Kch cny c coi l kch c chun (full-frame). i vi cc my nh s sau ny, ch nhng my c cm bin bng ng kch c ca phim (24 x 36 mm) mi c gi l my full-frame, v ch trn cc my

ny, ng knh mi th hin ng gi tr tiu c in trn ng knh . Cn cc my thay ng knh ckch c cm bin nh hn, khi lp ng knh, tiu c trn s phi nhn thm mt gi tr nht nh,gi tr ny chnh l crop-factor v n khc nhau ty thuc theo tng phin bn v tng nh sn xut.V d, mt ng 24mm khi lp trn thn my c crop-factor l 1.6x, ng knh ny s c tiu c l38mm.

Hu ht cc my nh s s, trung cp u c kch c cm bin APS-C vi thng s nhn hnh l 1,6xhoc 1,5x. Cc my h Micro Four Thirds c thng s nhn hnh 2x, ch c DSLR cao cp mi ckch c cm bin full-frame.

Nhip nh nng cao - Cch dng n flash Mt trong nhng k thut kh nht trong nhip nh l s dng nflash sao cho hiu qu nht.

Chun b Thit b: Bt k my nh thay ng knh no km mt ng knh v mt nflash ri. Mc tiu: Nm vng cch s dng n flash sao cho hiu qu nht. Thi gian: 15 pht


12/41

Hu ht cc my nh thay ng knh u c n flash tch hp (tr mt s phin bn nh Olympus E-P1, E- P2 hay cc my DSLR chuyn nghip). Mc d cc n tch hp ny t ra kh hu dng khichp nh, nhng ni chung, cc n ny vn cha hiu qu trong mt s trng hp nht nh.

khc phc nhc im ny, cc my thay ng knh thng c thm chu lp n flash ngoi.

Cc n lp ngoi ny c cng sut ln s dng trong hu ht cc trng hp. Nhng nukhng iu chnh ng cch, vi cng sut ln chng s d dng lm i tng c chp b chysng, hoc nu sng th hu cnh li ti en khin nh b bp v mt i chiu su cn thit.

Tm hiu v n flash lp ngoi

Cc b phn ca n flash. nh: Cnet Asia.

1. u ca n l ni cha bng pht sng. Mt s n c kh nng lt hay xoay theo cc gc khcnhau, cho php ngi chp c th ht sng theo nhiu hng khc nhau.

2. Thn n l ni c cc nt iu khin, mn hnh hin th v khoang cha pin.

3. Chu n c cc u ni tip xc vi cc tip im trn chu lp n thn my. Cc chu nychnh l phn my nh v n c th nhn v truyn lnh ln nhau. Mi nh sn xut s c cc cch b tr cc u ti tip xc khc nhau, v th n hng no ch c th dng trn my ca hng (trcc thit b n t cc hng th ba).


13/41

Mt s n c th lt xoay phn u theo nhiu hng khc nhau. nh: Cnet Asia.

S dng k thut ht sng

Nu bn cha thng n flash vo i tng, nh c th s tr nn qu chi. trnh tnh trng ny, bn nn lt u ca n flash hng cho ln trn nh sng p vo trn (nu trn thp) hoctng xung quanh i tng. Thao tc ny s lm cho nh sng c tri u trn ton b khungcnh xung quanh i tng, lm cho nh trng t nhin hn.


14/41

iu chnh gc pht sng ph hp. nh: Cnet Asia.

Nu n flash c sn tm nha ht sng pha u n, bn c th ko ht ra ri b u flash hngthng ln tri, khi chp nh sng s phn vo tm chn sng tch hp ny ri mi ta ln i tng,lm cho nh sng trn i tng u v gt hn. Nu khng c tm ht sng ny, bn c th khc phc bng cch ly bng dnh gn mt tm nha trng vo sau n thay th.

S dng cp ni di n

Dy ni di n flash. nh: Cnet Asia.


15/41

Nu c thm kinh ph, bn c th mua thm y ni di n flash. Vi dy ni ny, n khng nhtthit phi gn ln trn thn my na, v th bn hon ton c th iu chnh n ht t bn trn hay tmt bn ca i tng. K thut ny c th to nn nhng hiu ng th v nh ch chiu sng mt nai tng, to cm gic nh c chp t studio.

Mt s my nh chuyn nghip cn c th iu khin n flash t xa m khng cn dy ni. Nu mynh ca bn khng c chc nng , bn hon ton c th khc phc bng cch lp thm b truyn tnhiu khng dy gia my v n, bn cng s c c chc nng gn tng t.

Ch chnh tay

Cc n flash cao cp thng c thm chc nng cho php bn hiu chnh cng sut pht sng can. Chc nng ny cho php ngi chp iu chnh mt nh sng pht ra ph hp ty theotng trng hp c th. Hin nay mt s my thay ng knh cng c chc nng tng t i vin flash tch hp trn thn my.

K hiu TTL l g

Khi s dng vi n flash, bn thng hay c c cm t TTL. T ny c vit tt t"ThroughThe Lens" (qua ng knh). Khi mt n flash c cm bin o sng TTL tch hp, c ngha l n cth tng tc vi my nh bit chnh xc trong mt cnh nht nh, my nh s dng thng s phisng nh th no, t n s pht mt cng sut tng ng va chiu sng khung cnh.

Cc n flash hin ti u c nhng h thng o sng TTL rt tn tin, v th m nhiu nhip nh giathng khng cn quan tm ti vic hiu chnh thng s n na, h ch vic chiu n vo i tngv bm my.

Bc nh bn phi c chiu sng cn bng nh k thut chp htsng (n nghing gc 45 ), trong khi bc bn tri do chiu thngnn b bng pha sau. nh: Cnet Asia.


16/41

Khi cng sut n c iu chnh thch hp, nh trong s sng tnhin hn. nh: Cnet Asia .

S dng n flash ban ngy

C th bn s thc mc: Th cn vic dng n flash trong iu kin nh sng ban ngy th sao? Thc

ra nh trong bi v flash trn my du lch cng cp, trong nhng trng hp chp ngc sng(nh sng n t sau lng i tng), i tng lc ny s tr thnh bng en (silhouette). Lc ny sdng flash b sng cho tin cnh s lm i tng ni bt tr li. Trong trng hp ny, nh gimcng sut ca n, th chp mt vi ln vi vi mc khc nhau cho n khi c c mt bc nh ng.

"Topic ny ti m ra vi mc ch gip cung cp nhng kinthc cn bn cho cc bn mi BT U chp nh. V thi gian

cng c hn ch nn ti ch post ln y tng phn v s cgng post song song phn K thut chp cn bn. Hai phnny s h tr nhau gip cc bn nhanh chng t mnh chpc nhng bc nh nh .

Exposure (s phi sng)

Bn cht ca chp nh l s phi sng. My nh l mt hp ti.Khi bm nt chp nh, mt cnh ca c m ra cho nh sngbn ngoi i vo qua ng knh. nh sng tc dng vo film(hay sensor i vi my digital _ t sau y ti ch ni nfilm) to ra hnh nh. Mt bc nh ta c th tm chia lmhai phn : sng v s cn i nh sng. Ta hy hnh dung film l mt vt thu sng. V sng ca bcnh quyt nh bi lng nh sng m film thu c. Khi lngnh sng vo qu nhiu th nh s trng xa cn khng thnh s b ti. Mt bc nh c sng ng vi i tng cchp gi l ng sng.Ngoi yu t sng ra, s cn i nhsng khc nhau s to ra nhng bc nh hon ton khc nhau


17/41

vi cng mt sng. Lng nh sng film thu c gi l Ev ( Expoure value) .Chng ta s quay li phn Ev ny sau.

Trc ht bn s tm hiu nhng yu t nh hng n sng ca nh.

Apeture ( m ng knh)

m ng knh l phn iu chnh cng nh sng i quang knh. Chng ta c th hiu phn ny nh l kh nng chonh sng i qua ca ng knh. Cu to b phn ny bao gmnhng l mng ghp li to ra khe h dng hnh trn c thiu chnh c. Tng ng vi cc m ng knh ta c dytr s tiu chun 1 , 1.4 , 2 , 2.8 , 4 , 5.6 , 8 , 11 , 16 , 32 cc tr s ny gi l F -stop hay Khu . Ti mi F -stop ta cng knh l m d tng ng f/1, f/1.4 , f/2 f/2.8 v fchnh l di tiu c ng knh. Nh vy ta c th thy Khu cng ln th ng knh d cng nh v nh sng i qua ngknh cng t. V thm mt iu na l cng mt ng knh lm d nu di tiu c ng knh cng di th khu cng

ln.
http://www.vnphoto.net/data/p10/18_aperture_3d1_1808.jpghttp://www.vnphoto.net/data/p13/18_aperture1_1035.jpghttp://www.vnphoto.net/data/p10/18_aperture_3d1_1808.jpghttp://www.vnphoto.net/data/p13/18_aperture1_1035.jpg


18/41

* Cc bn thng hay thc mc ti sao dy tr s F -stop khngphi l 1 ,2 ,3 m l dy bi s ca cn bc hai ca 2. Trongk thut chp nh, ngi ta chn tiu chun iu chnh sngvi mt khong cch l gp i. Bn c th hiu l khi bn mng knh thm mt khu c ngha l lng nh sng thuc s tng gp hai ln. Mun nh th din tch l m phitng gp i tng ng vi ng knh tng ln 1.4 ln. l l do ti sao ta c dy tr s trn.

Shutter Speed (Thi chp hay tc )

Ngoi vic iu chnh cng nh sng i qua ng knh tacn c th iu chnh thi gian cho nh sng i vo thay i

sng ca nh chp. Yu t ny gi l thi chp hay tc chp. n v tnh l giy. Thi gian ny chnh l thi gian mn trp trong my m ra cho nh sng i vo. Thi gian ny cng lu (tc chm) thlng nh sng i vo cng nhiu v ngc li, thi gian nycng ngn (tc nhanh) th lng sng i vo s t i. Cng nh phn m ng knh, theo tiu chun th khi tngmt nc thi gian chp th lng nh sng i vo gp i. Tc chp nhanh hn 1s c 1/2 , 1/4 , .1/125, 1/250.Cn luhn 1s l 2, 4, 8 , 16s. Ngoi ra cn c k hiu B : mn chp m cho n khi bungtay bm nt chp. K hiu T : mn chp m cho n khi bm nt chp ln na.

Film speed ( nhy sng ca film)
http://www.vnphoto.net/data/p15/18_shutter_close1_8474.jpg


19/41

Yu t ny th hin kh nng hp th nh sng ca film.Cnhiu loi film khc nhau. Tuy nhin hin thng dng nht vnl film mu m bn .loi film ny d chp hn so vi cc loikhc nn thch hp cho cc bn mi bt u. Trn mi cunFilm bn s thy ghi nhy sng l 50 , 100 hay 200 ASAFilm 100ASA tc thu sng gp i so vi 50ASA v bngmt na so vi 200ASA. Film c nhy sng cng cao th hnhnh cng mn ht cng km.

*Phn tip theo:

Exposure Value (Ev)

Trong nhip nh, s kt hp ca m ng knh v tc chp cho ta mt i lng c trng gi l Exposure value(Ev). Ev 0 l khi ta t khu l 1 tc chp l 1 giy. Evc tnh bng kt hp hai hm logarit ca gi tr m ngknh (Apeture value) v gi tr ca thi chp (Time Value). EV = Av + Tv Gi N l tr s khu ( f -number) ta c Apeture value :

Nu t l thi chp tnh bng giy ta c Time Value:
http://www.vnphoto.net/data/p15/18_tv_425.jpghttp://www.vnphoto.net/data/p10/18_av_8860.jpghttp://www.vnphoto.net/data/p15/18_film_5948.jpghttp://www.vnphoto.net/data/p15/18_tv_425.jpghttp://www.vnphoto.net/data/p10/18_av_8860.jpghttp://www.vnphoto.net/data/p15/18_film_5948.jpghttp://www.vnphoto.net/data/p15/18_tv_425.jpghttp://www.vnphoto.net/data/p10/18_av_8860.jpghttp://www.vnphoto.net/data/p15/18_film_5948.jpg


20/41

Cc cng thc trn ch tham kho. Trong thc t th bn chcn hiu l vi khi bn m ng knh thm mt khu th thigian chp phi gim i mt na (hay ngc li) th Ev khngthay i. Cc bn cn lu mt im m cc bn mi chp haynhm ln l m ng knh thm mt khu ngha l gim f -number mt stop. V d nh t f/8 v f/5.6 .

nh sng tc ng vo film cn ph thuc vo nhy sngca film. nhy sng ca film th n gin nh khu haytc chp l tng gp i th lng sng vo s tng gp i.Film 100asa th gp i 50asa, 200asa th gp i film 100asaTy thuc vo iu kin chp khc nhau s c nhng chn lakhc nhau .Tuy nhin n gin th cc bn mi chp nncn c vo mc chun 100asa.

Quay li sng ca hnh chp, l kt qu ca vic da vonh sng ca ch , nhy sng ca film, khu v tc chp. nhy sng ca film th tt nhin l cng thp th hnhnh cng mn. Nhng khng phi iu kin no cng c thchn la film c nhy thp c. Chng ta s quay tr l ivn ny trong bi ni v film. Cn by gi n gin th

hy chn film 100asa v quan tm n khu v tc . Di y l bng gi tr Ev cc bn tham kho:


21/41

Trong bng trn, cc gi tr Ev ging nhau s nm trn mtng cho t gc di bn tri sang gc trn bn phi. Ngayti mt Ev no trong bng, dng thng sang bn tri vthng ln pha trn bn s tm c mt cp Khu v tc tng ng. Nhn trong bng bn s thy c nhiu cp khu khc nhau cho cng mt Ev. Nh vy khi chn khu v tc khc nhau th hnh nh s khc nhau nh th no? Phntip theo ti s trnh by v cc yu t lin quan khi bn chnkhu v tc c c bc nh nh .

Depth Of Field ( DOF)
http://www.vnphoto.net/data/p14/18_ev-table_5365.jpg


22/41

Mt thc t l khi bn chp mt bc nh, r nt khngxuyn xut. Khi bn canh nt vo ch th trc v sau ch s c khong khng r nt. Khong cch m nh cn r nttrc v sau im ly nt (tm) gi l su trng nh vthng gi tt l DOF. Khong r nt do nhiu yu t nh hng n. Tuy nhin yut u tin c th ni l m ng knh. Cc bn c th xem hnh minh ha sau y.


23/41


24/41

inch. S 3 v 4 r nt trong tt c cc hnh. Cc im cn li rnt dn khi m ng knh kha nh li. n y cc bn cth hiu rng khi ng knh khp nh li th khong r nt cngthu hp li.

Gii thch mt cht v khong r nt. Cc bn xem hnh bndi.

Ch l im mu vng v cng l im ly nt. V ly ntvo ch nn hin nhin cc tia sng t ch qua ng knhs hi t trn film. Cc im khc c cng khong cch vi ch u hin r trn film. By gi hy xem im mu trng xahn ch . im nh r ca im trng s nm pha trcfilm v nh ca n in trn film s l vng trn mu trng.Khong trng gi l Circle of Confusion ( CoC ). Vn t ra y l lm cch no thu hp vng trn lm nh r nt hn. Trong hnh minh ha di y, bnthy t mt im s c mt chm tia sng i qua ng knh vto nh trn mt phng film. Khi kha bt ca iu sng lingha l mt s tia sng b chn li ( phn mu xanh nht). Do phm vi ca CoC cng c thu hp li v hnh nh tr nnsc nt hn.
http://www.vnphoto.net/data/p15/18_coc_5567.jpg


25/41

Hyperfocal

Khi bn ly nt vo im xa v cc th hnh nh s r nt t vcc cho n mt khonhg cch no trc ng knh. Khongcch khng r nt trc ng knh khi bn ly nt v cc gi lHyperfocal.

Sau khi xc nh c khong hyperfocal bn ly nt li vokhong cch . Lc ny su trng nh DOF s bt u tgia khong hyperfocal n v cc. Thc t y l DOF lnnht m bn c th t c. Tuy nhin bn phi lu rngkhong cch hyperfocal ny khng c nh m ph thuc vokhu ng knh. mi F-stop th khong cch hyperfocal ukhc nhau.

Nh vy trong trng hp chp hnh cn ly dof tht rng, hnh
http://www.vnphoto.net/data/p13/18_hyperfocal2_2033.jpghttp://www.vnphoto.net/data/p14/18_hyperfocal1_5227.jpghttp://www.vnphoto.net/data/p15/18_coc1_1491.jpghttp://www.vnphoto.net/data/p13/18_hyperfocal2_2033.jpghttp://www.vnphoto.net/data/p14/18_hyperfocal1_5227.jpghttp://www.vnphoto.net/data/p15/18_coc1_1491.jpghttp://www.vnphoto.net/data/p13/18_hyperfocal2_2033.jpghttp://www.vnphoto.net/data/p14/18_hyperfocal1_5227.jpghttp://www.vnphoto.net/data/p15/18_coc1_1491.jpg


26/41

r nt trong phm vi ln nht th bn s ly nt vo khongcch hyperfocal kt hp vi ng nh m ng knh .

hyperfocal ch hiu qu khi dng vi ng knh gc rng v khpkhu nh li. Asahi tui gi gn trong ci bng sau cho cc bnd b ti.

Shutter Speed ( Tc hay Thi chp)
http://www.vnphoto.net/data/p15/18_hyperfocal-tablemini_840.jpg


27/41


28/41

Cng chp chic xe chuyn ng, nhng cc bn thy r rngtc chp cng chm th ch cng khng r. Khi chp nhkhng c chn my khng b rung tay thng thng sphi chp vi tc t 1/30s thm ch c th t 1/60s tr ln.

Chp vi tc chm hn, cn thit bn phi dng n chnmy.
http://www.vnphoto.net/data/p8/18_shutter1_198.jpg


29/41

Khi chp trong iu kin nh sng khng c kh nng chpvi tc chm c th bn s phi dng n knhlc ND (Neutral Density). Knh lc ny s gip bn gim cng sng vo ng knh. Ngc li khi chp ban m iu kinnh sng khng , bn phi c chn my chp vi tc chp chm. Ti s quay li phn knh lc ND ny chi tit hn sau bi ny.

Khi mun th hin s chuyn ng ca ch , bn s dng kthut lia my (paning). C ngha l khi chp my s c lia

bm theo ch . Khi ch s r nt, phng nn s lu

m .
http://www.vnphoto.net/data/p14/18_ubnd1_8344.jpg


30/41

i khi chp phong cnh, cn c s th hin mt chuyn ngno nh ma ri, nc chy .th bn cng s dng n tc chp chm hn. So snh hai hnh di y bn s thy hiuqu ca vic chp tc chm to ra hnh nh chuyn ng

ca dng sui.
http://www.vnphoto.net/data/p10/18_angelo2_1736.jpg


31/41
http://www.vnphoto.net/data/p11/18_suoi2_8543.jpghttp://www.vnphoto.net/data/p10/18_suoi1_7341.jpghttp://www.vnphoto.net/data/p11/18_suoi2_8543.jpghttp://www.vnphoto.net/data/p10/18_suoi1_7341.jpg


32/41

Cc ch chp cn bn

Trn my SLR hin nay u c h tr bng cc thit b int. Thng thng trn cc my s c 4 ch cn bn sauy:

1.Manual: (Th cng)

Cc thng s chp khu v tc s chn hon ton bngth cng. i khi bn c mun chp mt bc nh vi ccthng s khc bit dng nh d sng overexposure hay thiusng (underexoposure) bn s phi chn ch chp ny.K hiu trn my: M

2.Progaram: (T ng hon ton)

Hai thng s tc v khu s do my hon ton t chn.Cng vic cn li ca bn l ly nt v chp. K hiu trn my:P

3.Aperture- Priority ( Chn khu _ Tc chp t ng) Ch ny ngi chp s chn khu v tc chp s domy t ng a ra. Ch ny thng c chn kimsot vng nh r DOF. Tuy nhin cn lu khi nh sng thiuvic chn m ng knh b c th lm tc chp gim thpkhin nh b run tay. K hiu trn my A hay Av

4.Shutter speed- Priority ( Chn tc chp _ Khu do my

t chn) Ch ny ngi chp s chn trc tc chp, my s tng chn khu tng ng. Ch ny thng c chnkhi chp nh ng nhm kim sot hiu qu to ng trn nh.K hiu trn my S hay Tv

Trn y l cc ch cn bn. Cc nh sn xut cn thit kcc ch t ng khc nh chp th thao, chp phong cnh,chp chn dung th cc bn s xem trong hng dn i kmtheo my.


33/41

Neutral Density Filters ( Knh lc ND)

Tc dng ca knh lc ND l lm gim cng nh sng ivo ng knh. Sau khi gn knh lc ND, nu gi nguyn mng knh th tc chp s chm li, nu gi nguyn tc chp th ng knh phi m rng hn. Cc bn c th xem bngdi y.

ng mu th hin mt lng nh sng thu c (EV) trnng vi cc cp tc v khu c mt lng sngthu c ging nhau. Sau khi gn knh lc ND th ng bygi l ng t nt. V trn l hai v d v gi nguyn tc v gi nguyn m ng knh sau khi gn ND.

Trn knh lc ND c cc cch ghi thng s khc nhau. y tia ra hai dng thng gp

Dng th nht l theo m ca knh(density) v di y lbng th hin s gim khu tng ng (Reduction by f -stops).
http://www.vnphoto.net/data/p11/18_nd-diagram1_1932.jpghttp://www.vnphoto.net/data/p14/18_nd-diagram_575.jpghttp://www.vnphoto.net/data/p11/18_nd-diagram1_1932.jpghttp://www.vnphoto.net/data/p14/18_nd-diagram_575.jpg


34/41

V d nh hng Tiffen hay B&W c filter ND loi 0.3, 0.6 v 0.9 gim sng 1, 2 v 3 f -stop.

Cn hng Hoya hay Nikkon th dng thng s 2,4 hay 8 gim 1 , 2 hay 3 f -stop

Tt c cc knh lc ND u lc dng thang xm (gray)khng mu . Cc loi knh lc ND ch khc nhau v m nht gim sng nhiu hay t. Trong hnh di y l hai knh lcND4 v ND8 ca Nikon. Cc bn c th d dng nhn thybng ca ci ND8 th m hn ND4.

V d p dng knh lc ND

*Dng gim tc chp

Trong nhiu trng hp chp cnh ng chng ta phi chp vitc mn chp chm hn bnh thng to hiu quchuyn ng trn hnh nh ( motion blur). nh minh ha diy chp ch Av ( tc chp t ng). Chn khu f2.8 (tc chp chm nht) m hnh nh vn cn b bt ngdo nh sng qu mnh. tc chp c th chm hn ta

dng n knh lc ND. So vi khng dng knh lc ND th dngknh lc ND4 c tc chp bng 1/4 v knh lc ND8 c tc
http://www.vnphoto.net/data/p14/18_ndfilter_7103.jpg


35/41

chp bng 1/8.

Mt c im na ca knh lc ND l bn c th ghp nhiuknh chng ln nhau. V d knh ND4 + ND8 s gim cng nh sng 2+3= 5 f-stop

*Dng tng m ng knh.

Tc dng chnh ca knh lc ND l lm gim cng nh sngi vo ng knh.V iu ny c th gip chng ta m rng ngknh vi cng m tc chp nh nhau. C ngha l bn s

thay i c khong cch ca vng nh r (DOF). Trong cchnh minh ha di y dc chp ch Tv, tc chp l30. Hnh u tin bn tri khng dng knh lc nn hiu quxa phng cha cao. Hai hnh bn phi dng thm knh lc ND4v ND8 nn m ng knh tng 2 v 3 f -stop. Kt qu lkhong nh r thu hp li v ch ni bt hn trn phngnn b xa m. Trong trng hp nh sng qu gt cng c thdng hai knh lc ND ghp vi nhau ng knh c th mrng hn.
http://www.vnphoto.net/data/p11/18_ndfilter-ex2_6133.jpghttp://www.vnphoto.net/data/p10/18_ndfilter-ex1_6957.jpghttp://www.vnphoto.net/data/p11/18_ndfilter-ex2_6133.jpghttp://www.vnphoto.net/data/p10/18_ndfilter-ex1_6957.jpg


36/41

o sng v b sng.

Metering

H th ng o sng trong my chp cn bn c g i l TTL .Trong camera s c thi t b nh n v o nh sng ph n x t ch . V th c th ni thi t b o sng trong thn my lloi thi t b o sng ph n x . C lo i thi t b o cm tay ki uthu nh sng tr c ti p, nhng tr c h t chng ta s tm hi uv thi t b o sng trong my.

Cn bn th c 3 d ng o sng ( metering) trong thn my.

1. Matrix metering : o sng l y tr s trung bnh trn g n h tb m t hnh nh

2. Center metering : o sng trong m t vng nh trung tmhnh nh

3. Spot metering : o sng ti i m trung tm.

Ty theo c p my, c th khng c cc lo i o sng k trn ho c c thay i trong t ng lo i o sng. V i cng ngh hin nay th cc ch c nng o sng thay i kh nhi u. V
http://www.vnphoto.net/data/p12/18_metering_3029.jpg


37/41

d nh matrix metering c chia thnh nhi u im hn nn tr s trung bnh trn ton nh c o chnh xc hn. ng d ngcc lo i o sng ti s quay l i trong bi cn b n th c hnh.

Khi o sng, nh sng ph n x t ch rt a d ng. Mu s c, ch t liu .... nh hng n s ph n x nh sng nn n ukhng c m t tiu chu n o sng th khng c. V ng ita ch n mu xm gray 18% lm tiu chu n o sng. Do khi o sng trn thn my, b n c n ph i hng my o vovng g n v i mu xm gray18% nh t. Khi c n thi t c th dng mi ng gi y gray 18% t g n ch o sng.

Bn ch t c a thi t b o sng trong thn my nh gi i thch trn,nn khi ch p m c d o sng nhng chuy n hnh nhkhng ng sng v n x y ra l chuy n bnh thng. Ch nh h nnh trng h p hnh nh ton mu s c s c s ... th o sngtrong trong thn my kh chnh xc.

Compensation

Ti t m g i nh ng ch c mu sng nh mu tr ng ctbin, mu da ng i da tr ng, mu m t nc trong... l A . Muen ca than, mu da ngi da en , mu mt nc en...l B. V o sng b ng nh sng ph n x nn h th ng o sngtrong my r t d b sai. Trong tr ng h p ny ta th y r cngmt ngu n sng nh nhau nhng khi o sng gi a A v B c

th chnh nhau 2 n 3 F- stop. Cng v l do ny m trongthn my c o sng ph i h tr thm ch c nng b sng (compensation)

A nhi u mu tr ng nn tnh ph n xa nh sngcao B nhi u mu en nn tnh ph n xa nh sng th p

Khi o sng vo A th phi i u ch nh b sng theo h ng c ng(+) v khi o sng vo B th phi i u ch nh b sng theo


38/41

hng tr (-). H u h t cc my c ch c nng b sng u cth iu ch nh t ng n c 1/2 ho c 1/3 F-stop.

cc b n hi u r hn v ch c nng b sng, ti lm m t citest nh sau Hnh nh c ch p b ng ch Av, o sng spot metering. Hnh u tin ch p o sng vo Graycard 18% lm chu n.

Lot hnh ti p theo ch p o sng tr c ti p vo n n tr ng c axe
http://www.vnphoto.net/data/p12/18_graycard_6860.jpg


39/41

R rng cc b n d dng nh n th y n n tr ng c a xe lc nyc h xu ng c sng tng ng vi Graycard. cc n n tr ng th ph i b sng theoi hng tng (+).

t quy n catalog vo im o sng ta c kt ng c li nhsau:
http://www.vnphoto.net/data/p15/18_lightcompensation_5124.jpg


40/41

nh ch p ra tr nn d sng v my nng nn en c aquy n catalog c sng tng ng graycard. Lc nyc n ph i b sng theo h ng gi m (- ) c c n n enng vi th c t .

K t qu cho th y o sng c a my hon ton ph thu c vo sng c a im o sng do o sng bng phng th c ph n x .N u c graycard chu n hay my o sng tr c ti p th vi c o
http://www.vnphoto.net/data/p11/18_darkcompensation_6163.jpg


41/41

Documents

Nhiep anh.docx