He tuhinga mō ngā karaihe whakapā Tirohanga tawhiti Tirohanga tata
Ka taea te whakatikatika i te tirohanga tata o ngā kanohi mā te whakamahi i ngā karāhe mōhiti me ngā karāhe whakapā. Ka whakapirihia ngā karāhe mōhiti ki te karāhe, ko ngā karāhe whakapā ia ka whakapirihia ki te karu kanohi. He tawhiti motuhake tō ngā karāhe mai i te kanohi, ko ngā karāhe whakapā ia ka piri ki te kanohi kia kore ai e arohia te tawhiti i waenganui i te karāhe whakapā me te kanohi.
Ka whakamāramahia tētahi tauira o ngā raruraru e pā ana ki te tangata he tirohanga tata, he tirohanga tawhiti hoki, he aha ngā momo karaihe e whakamahia ana hei whakataurite i te tirohanga o ngā kanohi, he aha te roa arotahi me te kaha o te karaihe. Ka arotahi tēnei ki te whakamahinga o ngā karaihe whakapā hei whakataurite i te tirohanga tata me te tirohanga tawhiti.
Kanohi tirohanga tawhiti me ngā karaihe whakapā
Ko te tawhiti rawa atu ka kitea mārama e te tangata he kanohi tata te tirohanga he 50 cm. Kia mārama ai ngā kanohi tata ki ngā mea mutunga kore, whakatauhia (a) te momo karāhe arotahi e whakamahia ana, (b) te roa o te arotahi o te karāhe arotahi me te momo karāhe arotahi, (c) te kaha o te karāhe arotahi.
He tino tata ngā karāhe whakapā ki ngā kanohi, nō reira kaua e aro ki te tawhiti i waenganui i te karāhe me te kanohi. Ko te tawhiti i waenganui i ngā mea me te ahua me ngā karāhe whakapā ka kiia he rite ki te tawhiti i waenganui i ngā mea me te ahua me ngā kanohi.
Rongoā:
(a) Te momo karaihe i whakamahia
Mō te tirohanga tata, kua whakamāramahia ko te arotahi e whakamahia ana hei whakataurite i te tirohanga tata he arotahi kōpiko, he arotahi wehewehe rānei, he arotahi kino rānei.
(b) Te roa o te arotahi o te arotahi
Ko ngā mea e kitea ana e ngā kanohi titiro tata mā roto i ngā karāhe whakapā kei te tawhiti mutunga kore, nō reira me hanga e te karāhe he ahua i te tawhiti o te 50 cm ki mua i te karāhe whakapā. Kei mua i te karāhe te ahua, nō reira he mariko te ahua (whakatairitehia te whakamārama mō te hanganga ahua e te karāhe kōpiko).
Mōhiotia:
Ko te tawhiti o te mea (do) = mutunga kore
Ko te tawhiti o te ahua (di) = -50 cm (ko te tikanga kino he mariko te ahua)
E hiahiatia ana: Te roa arotahi (f)
Rongoā:
1/f = 1/do + 1/di
1/f = 1/~ + (- 1/50)
1/f = 0 – 1/50
1/f = – 1/50
f = – 50/1 henimita = -50 henimita = -0.5 mita.
He tōraro te roa arotahi, arā, he arotahi kōpiko te arotahi e whakamahia ana , he arotahi wehewehe rānei.
(c) Te kaha o te arotahi
P = 1/f = 1/-0.5 m = -2 Ngā Diopter
Ko te mana o te arotahi he -2 D. Ko te tohu kino he tikanga ko te arotahi e whakamahia ana he arotahi kōpiko, he arotahi wehewehe rānei.
Te tirohanga tata o te kanohi me ngā karaihe whakapā
Ko te tawhiti tata rawa atu ka kitea mārama e te tangata he kanohi tata kore ko te 50 cm. Kia taea ai e te tangata te pānui i te tawhiti o te 25 cm pērā i te kanohi noa, whakatauhia (a) te momo karāhe arotahi e whakamahia ana, (b) te roa o te arotahi o te karāhe arotahi, (c) te kaha o te karāhe arotahi.
He tino tata ngā karāhe whakapā ki ngā kanohi, nō reira kaua e aro ki te tawhiti i waenganui i te karāhe me te kanohi. Ko te tawhiti i waenganui i ngā mea me te ahua me ngā karāhe whakapā ka kiia he rite ki te tawhiti i waenganui i te mea me te ahua me ngā kanohi.
otinga
(a) Te momo karaihe i whakamahia
Ko te arotahi e whakamahia ana hei whakataurite i te tirohanga tata o ngā kanohi he arotahi pūkohu, he arotahi hūpeke rānei, he arotahi pai rānei.
(b) Te roa o te arotahi o te arotahi
Kia 25 cm te tawhiti o te mea e tirohia ana ki mua i te kanohi, me hanga e te karu arotahi he ahua i te tawhiti o te 50 cm i mua i te kanohi. Kei mua te ahua i te karu arotahi, nō reira he poutū, he mariko te ahua.
Mōhiotia:
Ko te tawhiti o te mea (do) = 25 cm
Ko te tawhiti o te ahua (di) = -50 cm (ko te tikanga kino he mariko te ahua)
E hiahiatia ana: Te roa arotahi o te karāhe whakapā
Rongoā:
1/f = 1/do + 1/di
1/f = 1/25 + 1/-50
1/f = 2/50 – 1/50
1/f = 1/50
f = 50/1 = 50 cm = 0.5 mita
Ko te roa arotahi he pai, ko te tikanga he arotahi kōpuku, he arotahi whāiti rānei, he arotahi pai rānei te arotahi e whakamahia ana.
(c) Te mana o te arotahi
P = 1/f = 1/0.5 = +2 Ngā Diopter
Ko te mana o te arotahi he +2 D. Ko te tohu pai he arotahi kōpikopiko, he arotahi hūpeke rānei te arotahi e whakamahia ana.
