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Liliensternus

18 Oct 2010 15:42



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Arata frumos, dar sunt curios daca spot-ul acopera un senzor DSLR APS-C (22.7 x 15.1 mm) si daca poate fi optimizat la un F8. 
Coma vad ca e o problema.

Cu toate ca un obiectiv cu doua lichide este atermalizat, cred ca in acest moment este o complicatie un pic prea mare asa ca am sa ma limitez la cele cu un singur lichid. Pe de alta parte oiectivul cu doua sorturi de sticla si doua lichide nu este ecromat, nici apocromat ci un superacromat....food for thought.

Dintre acestea cel din imaginile atasate pare a fi foarte promitator. 

Secventa este urmatoarea: BK7/550206/F2

SINGLE LIQUID APOCHROMAT
Radius   Thickness  Material
12.629    0.655        BK7
-17.975   0.084        550206
-1 2.785  0.220        F2
-44.155   48.804      Air
- 18.910  (Image surface)
EFL= 50.025 F/-= 10.0
Clear aperture = 5.0

"With this choice of materials, simultaneous correction
for chromatic aberration, spherical aberration, and
coma is not possible. With a liquid between the two
glass elements, the design is similar to a cemented
doublet. It is known that coma correction in cemented
doublets requires a careful choice of glasses. An
example of a glass-liquid apochromat (using normal
dispersion glass) corrected for chromatic aberration,
spherical aberration, and third-order coma is SK6/
550206/F8. This choice of glasses was not used in the
test objective as it was desired to demonstrate apochromatic
color correction using liquids and only the
most common normal dispersion glasses."

Cred ca momentan, acesta ar fi cel mai usor de realizat dpdv mecanic.

Am sa revin maine cu un proiect de celula care imi pare destul de rezonabil.