
diaphram (prakashiki)

prakashiki mein, ack diaphram ack patali apaardarshi sanrachana haye jisake kendra mein ack udghaatan (chhidra) hotaa haye. diaphram kii bhoomika prakaash key maarg koo "rokna" haye, sivaay prakaash key joe "aperture" seey gujarta haye. iss prakaar ise ack stop (ack aperture stop, yadi yeh fokal plain taka pahunchane vaale prakaash kii chamak koo seemit kartaa haye, yaa lens mein diaphram key anya upayogon key liye ack feeled stop yaa flair stop) bhee kahaa jaataa haye. diaphram koo ack lens yaa uddeshya key prakaash path mein rakhaa jaataa haye, aur chhidra kaa aakar lens key madhyam seey gujarane vaale prakaash kii matra koo niyantrit kartaa haye. diaphram key chhidra kaa kendra lens pranali key optical aksh key saath mell khaata haye. 
adhikansh aadhunik cameray ack prakaar key samayojya diaphram kaa upayog karate hain jise ack iris diaphram key roop mein jaanaa jaataa haye, aur aksar ise buss ack iris key roop mein sandarbhit kiya jaataa haye.
diaphram mein chhidra aur aff-sankhya parr lekhon koo photographic prabhaav aur alag-alag udghaatan kii matra kii pranali key liye dekhein.
iris diaphram banaam anya prakaar.
ack praakritik prakaash pranali jisamen ack diaphram aur ack chhidra hotaa haye, maanav aankh haye. iris diaphram haye, putali aperture haye. maanav aankh mein, iris donon koo sankuchit aur fail sakata haye, joe putali key aakar mein bhinn hotaa haye. aashcharyajanak roop seey, ack photographic lens joe apane chhidra (kundalakar sanrachana key beach mein chhed) key aakar koo lagaatar badalane kii kshamata rakhta haye, ack iris diaphram key roop mein jaanaa jaataa haye.
ack iris diaphram chhidra koo cumm karke detector seey takaraane vaale prakaash kii matra koo cumm curr sakata haye, aamtaur parr "pattiyon" yaa "blade" key saath joe ack vritt banaate hain.
photography key shuruati varshon mein, ack lens koo vinimeya diaphram key ack sett key saath fitt kiya jaa sakata thaa, jise aksar peetal key strips key roop mein jaanaa jaataa haye jise waterhouse stop yaa waterhouse diaphram key roop mein jaanaa jaataa haye. adhikansh aadhunik sthir aur video camers mein iris diaphram koo chala blade dwara samaayojit kiya jaataa haye, joe aankh kii iris kaa anukaran kartaa haye. 
diaphram mein dou seey bees blade hotey hain (aaj adhikansh lens mein paanch seey duss blade hotey hain), joe usa upkaran kii keemat aur gunavatta parr nirbhar kartaa haye jisamen iska upayog kiya jaataa haye. seedhe blade key parinamswarup diaphram key udghaatan key bahubhuj aakar mein hotaa haye, jabaki ghumaavdaar blade iris key udghaatan key goalpan mein sudhaar karate hain. ack tasveer mein, iris diaphram mein blade kii sankhya kaa anuman prakaash srot yaa ujjwal pratibimb seey abhisaran karane vaale vivartan spikes kii sankhya koo ginkar lagaaya jaa sakata haye. blade kii ack visham sankhya key liye, blade kii tulanaa mein doguni spikes hoti hain. 
blade kii ack samaan sankhya key mamle mein, prati blade dou spikes ack dusare koo overlap karenge, isaliye spikes kii sankhya dikhaai degi joe upayog kiye gaye diaphram mein blade kii sankhya hogi. yeh chhote chamkile dhabbon key saath andhere mein lii gaee tasveeron mein sabse adhik spasht haye, udaaharan key liye raat key shahar key drishya. kuchh cameray, jaise kii olympus xa yaa lens jaise mc zenitor-mee1, halanki, ack vargakar chhidra banaane vaale daahine konn vaale blade key saath dou-blade vaale diaphram kaa upayog karate hain.
isi tarah, prakaash key dhyaan seey baahar key bindu (bhram key vritt) samaan sankhya mein bhujaaon key saath bahubhuj key roop mein dikhaai dete hain kyonki chhidra mein blade hotey hain. yadi dhundhala prakaash golakar haye, tou yeh anuman lagaaya jaa sakata haye kii chhidra yaa tou goal haye yaa chhavi koo "chaude-khule" mein shoot kiya gayaa thaa (blade key saath lens key kinaaron mein peechhe hatna, lens bairal key aantarik kinare koo prabhaavi roop seey bunn jaane kii anumati denaa).
iris key khulane key aakar kaa "bokeh" naamak chhavi mein dhundhale out-off-phocus kshetron kii upasthiti key saath seedha sambandh haye. ack golakar udghaatan naram aur adhik praakritik kendrit kshetron kaa utpaadan kartaa haye.
kuchh lens kuchh prabhaav paida karane key liye vishesh roop seey aakar key diaphram kaa upayog karate hain. isamen rodenstock typhenbuilder-emagon, fuji aur simaa soft phocus lens key "diffusion disk" yaa "chaalani aperture", seabold key dreamgun key "sector aperture", yaa minolta/soney smooth trance phocus yaa fujifilm aeye. pee. dee. lens mein golakar appodisation filter shamil hain.
kuchh aadhunik swachaalit bindu-aur-shoot camers mein diaphram bilkul naheen hotaa haye, aur ack swachaalit aine. dee. filter kaa upayog karke chhidra parivartanon kaa anukaran karate hain. vaastavik diaphram key vipareet, iska kshetra kii gaharaai parr koee prabhaav naheen padata haye. ack vaastavik diaphram jaba adhik bund hoe jaayega tou kshetra kii gaharaai "badhegi" (i.ee., prishthabhoomi aur vishay donon koo ack hii samay mein adhik kendrit dikhaai detaa haye) aur yadi diaphram koo phir seey khola jaataa haye tou kshetra kii gaharaai "cumm" hoe jaayegi (i.ee.prishthabhoomi aur agrabhumi ack hii kendra tala key cumm seey cumm hissedar honge).
itihas.
apane 1567 key kaam "laa pratika della percepativa" mein venis key kuleen daniel barbaro (1514-1570) ney ack chitra sahaayata key roop mein ack baconvax lens key saath ack camera obscura kaa upayog karate hue varnit kiya aur bataaya kii chitra adhik jeevant haye yadi lens koo beach mein ack paridhi chhodane key liye utanaa hii cover kiya jaataa haye.
1762 mein, leonhard euler ney doorbinon key sambandh mein kahaa kii, "isi tarah tube key ander ack yaa adhik diaphram key saath prastut karna aavashyak haye, ack chhote golakar chhidra key saath chhidrit, sabhi baahari prakaash koo baahar karna behtar haye."
1867 mein, dzirre vaine monkoven, photographic optics parr sabse shuruati pustakon mein seey ack mein, photography mein "stop" aur "diaphram" key beach ack antar kheenchata haye, lekin optics mein naheen, kahate hainh
yeh antar deewaar key 1889 key "photography key shabdakosh" mein banaae rakhaa gayaa thaa (chitra dekhein), lekin ernst abbe key inn avadhaaranaon koo ekikrit karane key siddhant key baad gayab hoe gayaa.
rudolf kingslake key anusaar, iris diaphram kaa aavishkaarak agyaat haye. anya loga iss upkaran key liye joseph nicefore nieps koo shreya dete hain, 1820 key aspas. aich. shaahi sookshmadarshi samaaj key ack sadasya braun ney 1867 taka ack lokpriya behtar iris diaphram kaa aavishkaar kiya thaa.
kingslake mein kuchh anya diaphram prakaron key liye adhik nishchit itihas haye, jaise kii aim. 1856 mein noton kaa dou sliding squares kaa adjustable "catt aaee" diaphram, aur 1858 mein johnn waterhouse kaa waterhouse bund hoe gayaa.
hamberg vedhshala-bergdorff sthaan mein 60 semi (~ 23.6 inch) aperture vaalaa badaa apavartak thaa joe reposold aur steinhill (lens) dwara banaaya gayaa thaa. hamberg mahaan apavartak kii ack anoothi visheshta iris diaphram haye joe chhidra koo 5 seey 60 semi taka samaayojit karane kii anumati detaa haye. yeh doorbeen 1910 key dashak kii shuruat mein sakriya hui thee.

