Leitz minus aberration meaning

[Mustafa Umut Sarac]

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

 

[David Lyga]

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

 

[Mustafa Umut Sarac]

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

 

[ic-racer]

Nomenclature for negative and positive coma and spherical aberration.

Is negative aberration good thing or bad thing

Personally I prefer positive coma, where it seems to point into the picture frame, rather than pointing outward.

 

[Mustafa Umut Sarac]

ic-racer,

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

Umut

 

[Mustafa Umut Sarac]

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.

 

[Mustafa Umut Sarac]

negative coma

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

 

[ic-racer]

ic-racer,

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

Umut

Positive coma. They point inward toward the center.

 

[IloveTLRs]

Positive coma. They point inward toward the center.
View attachment 74023

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.

 

[Mustafa Umut Sarac]

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

 

[Mustafa Umut Sarac]

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

 

[Dan Fromm]

Study some more, you failed the examination. And look here: http://www.dioptrique.info/base/complements/courbes.HTM

 

[Mustafa Umut Sarac]

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.

 

[Dan Fromm]

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

 

[E. von Hoegh]

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.

If you think learning is degrading, try ignorance.

 

[Jim Jones]

If you think learning is degrading, try ignorance.

That's the best reply I've seen in a very long time!

 

[E. von Hoegh]

That's the best reply I've seen in a very long time!

Thank you. I can no more imagine living without thought and learning than I can imagine living without breathing.

 

[Mustafa Umut Sarac]

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.

 

[E. von Hoegh]

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.

Initiating ignore sequence... Done! Bye Mustafa.