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Double Gauss Designs
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woodrim



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PostPosted: Thu Dec 27, 2012 1:15 am    Post subject: Double Gauss Designs Reply with quote

I have posted this as a separate thread to make it easier to find in any future searches. Here are three charts of double gauss designs. You will need to click on the images to get one at a size that you can read.






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Lloydy



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PostPosted: Thu Dec 27, 2012 1:26 am    Post subject: Reply with quote

What we need now is a simple explanation of this type of lens design so that the simple folk, like me, can understand the basics of the design and the benefits, downfalls etc. I guess I'm not alone in hearing and reading about the different designs and not fully understanding and appreciating the differences, and more importantly the difference it makes when I press the button.
But remember ------ 'simple' Wink
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http://forum.mflenses.com/canon-a1-kit-with-lenses-and-flash-t68640.html

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http://forum.mflenses.com/sea-and-sea-t57172.html

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fermy



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PostPosted: Thu Dec 27, 2012 2:29 am    Post subject: Reply with quote

In simple terms it's the best design for a normal lens that can be hand calculated. The basic concept is clearly seen in the first lens here (Kodak Ektar): two convex lenses separated by air followed by their mirror image. The design is symmetric. The key advantage of design is that it allows good correction of various aberrations, allowing for very fast lenses. The disadvantage is that double-Gauss have a lot of glass-air surfaces, so require coating.

The designs that were popular before double Gauss: Tessar and Sonnar have fewer glass-air surfaces and can function uncoated. However, they have more aberrations, will be noticably weaker away from the center than double Gauss, but will have better contrast given the same coating. In practice, one might prefer Sonnars for portrait lenses as uncorrected spherical aberrations will result in smoother rendering.
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Lightshow



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PostPosted: Thu Dec 27, 2012 3:36 am    Post subject: Reply with quote

Thanks for the diagrams.Smile
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patrickh



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PostPosted: Thu Dec 27, 2012 4:25 am    Post subject: Reply with quote

Fascinating


patrickh
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DSLR: Nikon D300 Nikon D200 Nex 5N
MF Zooms: Kiron 28-85/3.5, 28-105/3.2, 75-150/3.5, Nikkor 50-135/3.5 AIS // MF Primes: Nikkor 20/4 AI, 24/2 AI, 28/2 AI, 28/2.8 AIS, 28/3.5 AI, 35/1.4 AIS, 35/2 AIS, 35/2.8 PC, 45/2.8 P, 50/1.4 AIS, 50/1.8 AIS, 50/2 AI, 55/2.8 AIS micro, 55/3.5 AI micro, 85/2 AI, 100/2,8 E, 105/1,8 AIS, 105/2,5 AIS, 135/2 AIS, 135/2.8 AIS, 200/4 AI, 200/4 AIS micro, 300/4.5 AI, 300/4.5 AI ED, Arsat 50/1.4, Kiron 28/2, Vivitar 28/2.5, Panagor 135/2.8, Tamron 28/2.5, Tamron 90/2.5 macro, Vivitar 90/2.5 macro (Tokina) Voigtlander 90/3.5 Vivitar 105/2.5 macro (Kiron) Kaleinar 100/2.8 AI Tamron 135/2.5, Vivitar 135/2.8CF, 200/3.5, Tokina 400/5,6
M42: Vivitar 28/2.5, Tamron 28/2.5, Formula5 28/2.8, Mamiya 28/2.8, Pentacon 29/2.8, Flektogon 35/2.4, Flektogon 35/2.8, Takumar 35/3.5, Curtagon 35/4, Takumar 50/1.4, Volna-6 50/2.8 macro, Mamiya 50/1.4, CZJ Pancolar 50/1,8, Oreston 50/1.8, Takumar 50/2, Industar 50/3.5, Sears 55/1.4, Helios 58/2, Jupiter 85/2, Helios 85/1.5, Takumar 105/2.8, Steinheil macro 105/4.5, Tamron 135/2.5, Jupiter 135/4, CZ 135/4, Steinheil Culminar 135/4,5, Jupiter 135/3.5, Takumar 135/3.5, Tair 135/2.8, Pentacon 135/2.8, CZ 135/2.8, Taika 135/3.5, Takumar 150/4, Jupiter 200/4, Takumar 200/4
Exakta: Topcon 100/2.8(M42), 35/2.8, 58/1.8, 135/2.8, 135/2.8 (M42), Kyoei Acall 135/3.5
C/Y: Yashica 28/2.8, 50/1.7, 135/2.8, Zeiss Planar 50/1.4, Distagon 25/2.8
Hexanon: 28/3.5, 35/2.8, 40/1.8, 50/1.7, 52/1.8, 135/3.2, 135/3.5, 35-70/3.5, 200/3.5
P6 : Mir 38 65/3.5, Biometar 80/2.8, Kaleinar 150/2.8, Sonnar 180/2.8
Minolta SR: 28/2.8, 28/3.5, 35/2.8, 45/2, 50/2, 58/1.4, 50/1.7, 135/2.8, 200/3.5
RF: Industar 53/2.8, Jupiter 8 50/2
Enlarg: Rodagon 50/5,6, 80/5,6, 105/5.6, Vario 44-52/4, 150/5.6 180/5.6 El Nikkor 50/2,8,63/2.8,75/4, 80/5,6, 105/5.6, 135/5.6 Schneider 60/5.6, 80/5.6, 80/4S,100/5.6S,105/5.6,135/5.6, 135/5.6S, 150/5.6S, Leica 95/4
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RAART



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Joined: 10 Oct 2012
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PostPosted: Thu Dec 27, 2012 4:49 am    Post subject: Reply with quote

Captivating!
Idea
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Pentax K3

FOR SALE:

Do you have Pentax-A or F or FA primes and like to trade?

Here is the list what I have to trade/sale:
Primes - Kiron 28mm f2 (C/Y); Vivitar 28mm f2.5 Auto (FD); Minolta MD 50mm f2 (incl. adapter to m4/3); Miranda Auto 35mm f2.8 EC (incl. adapter to m4/3); Miranda Auto 135mm f2.8 EC (incl. adapter to m4/3);
Zoom – AF Sigma APO 70-210 f2.8 in Nikon mount, 2nd version with 82mm filter diameter and Soligor filter since day one (original owner)
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tromboads



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PostPosted: Thu Dec 27, 2012 8:32 am    Post subject: Reply with quote

.. Hears the pokemon theme song.. Got a catch em all, double gause!
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Excalibur



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PostPosted: Thu Dec 27, 2012 9:16 am    Post subject: Reply with quote

Very interesting but doesn't explain why some lenses are sharper\better than others (ignoring misuse or bad copy or type of glass)..e.g why is the Minolta PG 50mm f1.4 sharper than the Minolta PF 58mm f1.4 and similar comparisons. Or why everyone praises the RE Topcor 58mm f1.4 but ignores the Minolta PF 58mm f1.4 manufactured roughly at the same time......is the answer simply:- Minolta are inferior compared to Topcon in turning out lenses, so pick your own examples and wonder why Question
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.........past gear Tele Rolleiflex and Rollei SL66.
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casualcollector



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PostPosted: Thu Dec 27, 2012 1:04 pm    Post subject: Reply with quote

Excalibur wrote:
Very interesting but doesn't explain why some lenses are sharper\better than others


Different goals on the designer's part. Different capabilities of the manufacturer. Economic considerations (selling price). Different quality standards of makers. Sample variation. Differing tastes of user.

I have an issue of Camera 35 Magazine from 1971. The Canon F-1, Pentax Spotmatic F and Mamiya/Sekor Auto XTL were tested with their f-1.4 standard lenses. I believe this was a test chart on film test. The Canon had the best numbers with Pentax and Mamiya falling in behind. Today it seems the Pentax Super Takumar is the most highly praised and desirable of the group, judged by the comments of this forum.
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Found: 135/2.8 #R407660, 200/4 #R405526, 300/5.5 #R411127
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Mos6502



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PostPosted: Thu Dec 27, 2012 1:51 pm    Post subject: Reply with quote

One lens up there is a tessar variant, not a double guass, can you spot it? Smile

casualcollector wrote:
Excalibur wrote:
Very interesting but doesn't explain why some lenses are sharper\better than others


Different goals on the designer's part. Different capabilities of the manufacturer. Economic considerations (selling price). Different quality standards of makers. Sample variation. Differing tastes of user.

I have an issue of Camera 35 Magazine from 1971. The Canon F-1, Pentax Spotmatic F and Mamiya/Sekor Auto XTL were tested with their f-1.4 standard lenses. I believe this was a test chart on film test. The Canon had the best numbers with Pentax and Mamiya falling in behind. Today it seems the Pentax Super Takumar is the most highly praised and desirable of the group, judged by the comments of this forum.


One thing is that designers had to work around each other presumably, some designers were just better than others, or had other goals (ie. speed vs. sharpness, or aberrations vs. distortion etc.) so lenses of similar design perform differently, and as pointed out constraints of selling price, materials, etc. also make differences.

Lenses which are in "convenient" mounts like M42 will be more popular these days than lenses in esoteric mounts, which pretty much explains why the Takumars are more popular than other lenses which are as good or better but only available in other mounts.
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Keysersoze27



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PostPosted: Thu Dec 27, 2012 2:03 pm    Post subject: Reply with quote

Woodrim very nice work !!!!!

You could also add the Fujinon 55 f1.8 and use the Zuiko Auto-S 50mm f1.8 diagram since it is the same at 98% Wink

Also the Yashica line of 50mm lenses is also in the same category...
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28mm: Zeiss Distagon 2.8/28 MMJ
35mm: CZ Distagon 2/35 ZE , S-M-C Takumar 3.5/35
40mm: CZJ Tessar T 4.5/40 1Q
50mm: CZ Planar 1.4/50 MMJ,CZ Planar 1.7/50 AEJ+MMJ,Leica Summicron 2/50 v3,S-M-C Takumar 1.4/50,Pentax SMC 1.4/50 K,Pentax SMC 1.8/55 K,Nikkor 1.8/50 ,CZJ Tessar T 3.5/50 1Q , CZ Planar 1.8/50 (QBM),Zuiko 1.4/50, Zuiko 1.8/50, Icarex Tessar 2.8/50, Nikkor 2/50 Ai,Schneider Kreuznach Xenar 2.8/50 Preset, Pentacon Prakticar 2.4/50 MC v1, CZJ Pancolar 1.8/50 Zebra , Rikenon 1.4/50 P
55mm: Fujinon 1.8/55 EBC
58mm: Helios MC 44-3 2/58
85mm: Zeiss Sonnar 2.8/85 AEJ
90mm: Voigtländer APO-Lanthar 3.5/90 SLII , Leica Elmarit-R 2.8/90 v2
100~105mm:Zeiss Sonnar 3.5/100 MM, Nikkor 2.5/105 AiS, S-M-C Takumar 2.8/105
135mm: Leica Elmarit R 2.8/135 v2, S-M-C Takumar 3.5/135, CZJ 4/135 Sonnar Exakta leatherette (1963),CZJ 4/135 Triotar
Macro:Leica Macro-Elmarit R 2.8/60, Micro-Nikkor Auto 3.5/55 Compensating type (1964)
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woodrim



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PostPosted: Thu Dec 27, 2012 2:27 pm    Post subject: Reply with quote

To me, the most interesting thing was to find the Vivitar 90/2.5 Series 1 Macro there; one of my favorite and treasured lenses. Who were Opcon?
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Excalibur



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PostPosted: Thu Dec 27, 2012 3:05 pm    Post subject: Reply with quote

casualcollector wrote:
Today it seems the Pentax Super Takumar is the most highly praised and desirable of the group, judged by the comments of this forum.


...........or until recently (e.g Nex) most Digital users couldn't use old Canon FD lenses (well they could but it was inconvenient and with some problems) so less comments made Question
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Canon A1, AV1, T70 & T90, Contax 139, Fuji STX-2, Konica Autoreflex TC, FS-1, FT-1 & C35, Minolta X-700, X-300, SRT101b and AFZ, Nikon L35ad, RF2, EM, N2000 and F401, F90X, Olympus Om20 & OM2, Pentax S3, Praktica MTL3, TL 5B, & BC1, , Ricoh KR10super, Yashica T5D, Bronica Etrs, Mamiya RB67 pro AND drum roll:- a Sony DSC-P92
.........past gear Tele Rolleiflex and Rollei SL66.
Many lenses from crap to excellent.
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tromboads



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PostPosted: Thu Dec 27, 2012 10:30 pm    Post subject: Reply with quote

A Tessar.... Your eyes are doing better then mine, we need 3 systems, er groups, and fourish elements?



Mos6502 wrote:
One lens up there is a tessar variant, not a double guass, can you spot it? Smile

casualcollector wrote:
Excalibur wrote:
Very interesting but doesn't explain why some lenses are sharper\better than others


Different goals on the designer's part. Different capabilities of the manufacturer. Economic considerations (selling price). Different quality standards of makers. Sample variation. Differing tastes of user.

I have an issue of Camera 35 Magazine from 1971. The Canon F-1, Pentax Spotmatic F and Mamiya/Sekor Auto XTL were tested with their f-1.4 standard lenses. I believe this was a test chart on film test. The Canon had the best numbers with Pentax and Mamiya falling in behind. Today it seems the Pentax Super Takumar is the most highly praised and desirable of the group, judged by the comments of this forum.


One thing is that designers had to work around each other presumably, some designers were just better than others, or had other goals (ie. speed vs. sharpness, or aberrations vs. distortion etc.) so lenses of similar design perform differently, and as pointed out constraints of selling price, materials, etc. also make differences.

Lenses which are in "convenient" mounts like M42 will be more popular these days than lenses in esoteric mounts, which pretty much explains why the Takumars are more popular than other lenses which are as good or better but only available in other mounts.
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skida



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PostPosted: Fri Dec 28, 2012 2:23 am    Post subject: Reply with quote

I have to admit doing a search on "Double-Gauss" Embarassed

Clever bloke, that Carl Friedrich Gauss: when he wasn't playing with magnets he was designing telescope lenses!
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