Leitz minus aberration meaning

Discussion in 'Camera Building, Repairs & Modification' started by Mustafa Umut Sarac, Sep 4, 2013.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I found that leitz summitar have negative spherical and coma aberration . Is negative aberration good thing or bad thing and if it is a good thing , how it comes at a picture ?

    Umut
     
  2. David Lyga

    David Lyga Subscriber

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    Mustafa, the only thing I can say regarding this 'negative' formulaic determination is that it just might balance out the other elements. So many elements are used to counter the bad effects of the others. That is why (especially) wide angles have so many surfaces: wides are the most difficult to correct. Read this:

    http://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations

    - David Lyga
     
  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    David, yes, negative, positive aberrations are used for balance each other. But it opens a new questions , is it explains everything. I have a Ektar ,my mother and I agree , when you look from the back of the lens , skin details, shadows, lines, 3d curves are faraway being increased and visible. Faraway, different than the eye sees. Why ? Are these high aberrations and compensartions used for something also ?

    Umut
     
  4. ic-racer

    ic-racer Member

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    Nomenclature for negative and positive coma and spherical aberration.
    posandnegcoma.jpg
    nmd_suppl_april_a03_fig01.jpg

    Personally I prefer positive coma, where it seems to point into the picture frame, rather than pointing outward.
     
    Last edited by a moderator: Sep 4, 2013
  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    ic-racer,

    Thank you very much, first time I have ever saw such graphs. Can you explain first graph and your preferenment ?

    Umut
     
  6. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    That is interesting about sph. aberration.

    Since the effective focal point determines the position of the image for any object, the fact there are several different focal points for the different kinds of rays means that there are several “ghost” images formed by the lens – the “real” one determined by the location of the paraxial-ray focal point, and a number of other images that are formed at different distances depending on where the rays that form them struck the lens.
     
  7. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    negative coma

    when coma is negative, the image produced by the off-axis rays is slightly smaller.
     
  8. ic-racer

    ic-racer Member

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    Positive coma. They point inward toward the center.
    nh_MA__pin_coma.jpg
     
  9. IloveTLRs

    IloveTLRs Member

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    So that's what that is called. My Summitar has displayed this effect, shot at f2 at infinity. I can't say I like the effect at all.
     
  10. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    How do you analysis below charts of Leitz Wetzlar Summitar Design Analysis ?

    00701$.GIF

    00701.GIF

    00701-.GIF

    00701~.GIF
     
  11. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    o3o-3k4f
    Nº de calcul 701
    Nom Summitar
    Inventeur _/_
    Maison Leitz
    Formule 22/21
    Date 1939
    Focale nominale (mm) 98,52
    Focale réelle (mm) 99,99
    Ouverture nominale f/2,
    Ouverture réelle f/2,
    Nb de dioptres 11
    Nb de lentilles 7
    Angle de champ nominal (ºdec) 45,00
    Angle de champ (ºdec) 45,00
    Diagonale image 82,83mm
    Format couvert 47x70mm (59mm)
    Nº dioptre diaph. 6
    Distance diaphragme (mm) 11,60
    Distance objet (mm) Infini
    Tirage à l'infini (mm) 68,38
    Pupille objet (mm) 44,24
    Pupille image (mm) -32,96
    Vignetage relatif (%) -30
    Pertes (%) 36,97
    Commentaire: DE 0 685 572


    Nº Rayon Indice Epaisseur H. nominales H. maximales
    0 XXXX Air XXXX
    1 68,860 1,53380 10,800 27,497 28,304
    2 -122,960 1,67270 3,000 26,964 27,635
    3 -1956,500 Air 0,200 25,492 25,492
    4 33,250 1,67000 9,800 22,304 22,304
    5 46,230 1,66450 3,000 19,803 19,803
    6 23,510 Air 20,700 17,162 17,162
    Diaphragme
    7 -28,230 1,56730 3,000 16,289 16,289
    8 88,530 1,62040 10,800 19,921 23,278
    9 -37,870 Air 0,200 20,649 23,151
    10 -1956,500 1,60740 4,900 20,228 25,302
    11 -67,090 Air XXXX 20,112 25,331

    Nº Indice C Indice F
    0 --- ---
    1 1,53088 1,54051
    2 1,66661 1,68752
    3 --- ---
    4 1,66576 1,67995
    5 1,65906 1,67758
    6 --- ---
    Diaphragme
    7 1,56337 1,57661
    8 1,61727 1,62755
    9 --- ---
    10 1,60415 1,61487
    11 --- ---



    Sommes de Seidel: Etats par dioptres
    Nø Ab. Sphé. Coma Ast. Sag. Ast. Tan. Ast. Tot. Dist. Petzval
    1 0,695 -0,171 -0,547 -0,632 0,042 -1,348 -0,505
    2 -0,327 -0,297 0,315 0,855 -0,270 -2,860 0,044
    3 0,241 0,429 -0,784 -2,312 0,764 13,958 -0,021
    4 0,923 -0,152 -1,232 -1,282 0,025 -2,032 -1,206
    5 0,000 -0,001 0,001 -0,005 0,003 0,054 0,004
    6 -2,204 0,627 1,876 2,233 -0,178 5,337 1,698
    Diaphragme
    7 -3,824 -1,400 1,795 2,820 -0,513 -6,572 1,282
    8 0,084 -0,089 -0,119 -0,309 0,095 -1,262 -0,024
    9 2,391 0,558 -1,141 -1,402 0,130 2,665 -1,011
    10 -0,034 -0,098 0,300 0,861 -0,281 -8,609 0,019
    11 2,377 0,591 -0,710 -1,004 0,147 1,765 -0,563
    Total 0,323 -0,003 -0,247 -0,176 -0,036 1,097 -0,283


    Sommes de Seidel: Totaux par dioptres
    Nº Ab. Sphé. Coma Ast. Sag. Ast. Tan. Ast. Tot. Dist. Petzval
    1 0,695 -0,171 -0,547 -0,632 0,042 -1,348 -0,505
    2 0,368 -0,469 -0,233 0,224 -0,228 -4,207 -0,461
    3 0,609 -0,039 -1,017 -2,088 0,535 9,750 -0,482
    4 1,532 -0,192 -2,249 -3,370 0,560 7,718 -1,688
    5 1,532 -0,192 -2,248 -3,375 0,564 7,773 -1,684
    6 -0,672 0,435 -0,372 -1,142 0,385 13,110 0,014
    Diaphragme
    7 -4,495 -0,966 1,423 1,678 -0,127 6,538 1,296
    8 -4,411 -1,055 1,305 1,369 -0,032 5,276 1,272
    9 -2,021 -0,497 0,163 -0,033 0,098 7,941 0,261
    10 -2,055 -0,594 0,463 0,828 -0,182 -0,668 0,281
    11 0,323 -0,003 -0,247 -0,176 -0,036 1,097 -0,283
    Total 0,323 -0,003 -0,247 -0,176 -0,036 1,097 -0,283


    Valeurs des aberrations du 3ème ordre:
    % Ab. Sphé. Coma Ast. Sag. Ast. Tan. Ast. Tot. Courb. Dist.
    10% -0,010 -0,010 -0,019 -0,014 0,005 -0,016 0,000
    20% -0,039 -0,039 -0,075 -0,054 0,021 -0,065 0,003
    30% -0,085 -0,084 -0,165 -0,122 0,043 -0,144 0,009
    40% -0,142 -0,141 -0,284 -0,218 0,067 -0,251 0,022
    50% -0,204 -0,201 -0,427 -0,341 0,086 -0,384 0,042
    60% -0,261 -0,254 -0,583 -0,493 0,089 -0,538 0,074
    70% -0,299 -0,284 -0,742 -0,676 0,066 -0,709 0,119
    80% -0,298 -0,268 -0,892 -0,890 0,001 -0,891 0,179
    90% -0,233 -0,173 -1,017 -1,138 0,122 -1,077 0,258
    100% -0,074 0,049 -1,099 -1,417 0,318 -1,258 0,358
     
  12. Dan Fromm

    Dan Fromm Member

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  13. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Dan , I am sure I failed. Collecting information little by little is good for young people , its joyful but after 40 years , it is degrading.
     
  14. Dan Fromm

    Dan Fromm Member

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    Mustafa, I am older than you. It is impossible to stop learning, learning never gets easier, and it is ennobling, not degrading.
     
  15. E. von Hoegh

    E. von Hoegh Member

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    If you think learning is degrading, try ignorance.
     
  16. Jim Jones

    Jim Jones Subscriber

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    :laugh: That's the best reply I've seen in a very long time!
     
  17. E. von Hoegh

    E. von Hoegh Member

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    Thank you. I can no more imagine living without thought and learning than I can imagine living without breathing.
     
  18. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I will be glad to see what you learned in these years with your photographs but you select to stay ignorant and your short hidden guerilla post attacks reveals what you ever thinked in those years.
     
  19. E. von Hoegh

    E. von Hoegh Member

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    Initiating ignore sequence... Done! Bye Mustafa.