Fifty: Six to Five or Six to Four. Three Planar formula lenses compared.

Sonnar Brian

Sonnar Brian

Product of the Fifties
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I picked up the Hexanon 50mm F1.9 in Leica mount this week. This is a six element in five group design, as is the Minolta 5cm F1.8 that I picked up a few years ago. The 6/5 configuration is attributed to the Voigtlander Ultron. I also brought the Canon 50mm F1.8 v2- mine is an early one, more aperture blades and has perfect glass. The Canon is a traditional 6/4 "Asymmetric" double-Gauss, that is attributed to the Opic of 1920. The Opic achieved the F2 speed by introducing slight asymmetry into the double-Gauss formula.

Note 1 about the Hexanon: it uses 39.5mm filters. Later versions seem to have switched to 40.5mm. I found a Series VI adapter ring that was close enough to fit. I ordered a 39.5mm S-VI adapter.

The Canon uses 40mm filters. Uncommon, but more available than 39.5mm. Finding a Canon 50/1.8 v2 with perfect glass takes patience. Many have been destroyed from lubricants seeping onto the surface behind the aperture. The newer type glass used by Canon etches easily. This example is an early lens. I speculate that the lubricant was changed sometime in the production. Later lenses have less aperture blades. This one has 11, later ones have 8.

The Minolta uses 46mm filters- the front element is larger than the Canon front element and larger than the Hexanon front element.

Prices on all of these lenses are down from a few years ago. Expect to pay $150~$200 for a clean Canon V2. The Minolta - expect $250~$350. The Konica, $275~$400.


M9 at ISO2500. More to come later.

Hexanon wide-open:
L1027203.jpg


Canon wide-open, same filter as used on the Hexanon:

L1027255.jpg



Minolta wide-open:

L1027296.jpg
 
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ISO160. Lighting from the skylight, partially cloudy day- sun in and out.

Konica wide-open:

L1027182.jpg


Canon wide-open:

L1027227.jpg


Minolta wide-open:

L1027272.jpg
 
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Lenses appear to have similar rendering, all are pretty good, nice to be able to work with good examples of each!. I notice that the Konica is odd man out in the first set, the Canon and Minolta lenses appear to provide a bit cooler (blue-shifted) colors than the Konica.
 
My Hexanon has a 40.5mm filter. Did not know that the earlier ones were different. I use the Hex exclusively on film, where it is just fantastic and renders color well on modern color films, unlike a number of other mid-1950s / early 60s lenses. What is your verdict on these three lenses on digital? My eyesight is not as good as it used to be. 🙂.
 
Agree with Dexdog- the Konica is warmer than the Minolta and Canon. I used the same filter on the Konica and Canon: the difference is due to the lenses. The Minolta- used same type filter. To get a slightly warmer color on the Canon and Minolta to suit taste- I would go with a Skylight 1B.

The lenses- all perform similarly. I cannot tell even in full 1:1 on the DNG files which is sharper, all are in the same league. Rendering is similar.

So which one will I keep?
That's a laugh. Like I would ever sell one of these.
 
Color rendition - people tend to favor warmer colors.

The Konica has a warmer cast.
The Canon is cooler.
The Minolta- neutral based on recalling the subjects.

Someday I'll tripod mount the camera, shoot a color image with all three, and do a histogram.
 
I hope you don't mind me asking, but what exactly defines a Planar vs a "standard" Double Gauss?

The reason I ask is that I finally got a chance to take my Helios-103 out on a decent body since I picked up my Amedeo adapter a while back, and that lens has always impressed me for a ~$50 lens (and yes, I'm aware of the absurdity of using a $400 adapter to play with a $50 lens):

Leica IIIg - Helios (small).jpg

(Shot on Fomapan 100 in Rodinal, for what it's worth.)

Now I've always thought this was a Double Gauss, and the old Soviet Cams site says it's six elements in three groups:
1693306098084.png

And true enough, comparing this with the lens design for the LTM Canon 50/1.8 from Canon Rangefinder, I don't see a whole lot of difference:
1693306142625.png

And here's the optical design for the LTM Minolta 50/1.8, which has the obvious air gap at the front, but is also very similar:

1693306437210.png

Is it the curve in the middle of the rear group that changes the definition of the design from a Double Gauss to a Planar? And does that have a consistent and noticeable effect in the rendering of the lens compared to a "straight" Double Gauss like a Helios or a Summicron?
 
The original Double-Gauss lens was Symmetric, the front and rear elements- the same. Using symmetric components back-to-back corrected aberrations. The problem: it also limited maximum apertures to a very modest F4.5 or so. The Planar uses symmetric doublets in a 1-2-2-1 configuration. H.W. Lee of Taylor, Taylor, and Hobson kept the same configuration, but introduced a change to the focal length of the rear section to make it Asymmetric and was able to increase the aperture to F2. The Zeiss version of this lens was named the Biotar. Later on- Zeiss just started applying the "Planar" name to their versions of the Opic.

The 6/5 version of the Ultron, Minolta, and Hexanon are all six elements in 5 individual groups- more than an air-gap. Minolta used "Air-Spaced" groups in the 5cm F2, 7 element in 4 group lens- based on the Summitar. The Summitar uses cemented pairs instead of air gaps. Air-Gapped groups are also used in the Collapsible Summicron and first type Rigid Summicron. This is why a spec sheet labels a Summicron as a 7 element in 4 group design, the front groups are air-spaced doublets. Some people mistakenly call the early Summicrons a 7/6.
 
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So if I'm understanding this correctly, the Helios-103 is closer to the original Planar than the Canon and Minolta lenses mentioned here?

Also, I find it amusing/confusing that, as mentioned, the Helios is described over at Soviet Cams as being in three groups, while the Canon 50/1.8 design is apparently four groups. I assume that must be a mistake on Soviet Cams' part?

(In case it isn't obvious, lens design definitions confuse the hell out of me!)
 
The Helios-103 and Menopta 53/1.8 (export version, made in the 90s) are Asymmetric, the front and rear sections are different focal lengths. Similar to the Canon 50/1.8.
The Soviet Cams reference, must be a typo. This lens is always listed as a 6 element in 4 group design.

Many years ago I bought two Lots of Six Menopta 53/1.8 lenses. Set half for Nikon S-Mount and the other half for Contax mount.
Most- I shimmed for Nikon mount. The earlier Helios-103, up to 1982: have a secondary Shim for the rear section. Remove it- get a reduced focal length for the lens. I also Blackened the aperture blades for it, removed flare when using the lens stopped down. I've paid as little as $2 for a Helios-103 and spent hours working on them.
 
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The 39.5mm to Series VI adapter arrived, and works perfectly. I have never seen a 39.5mm filter before, let alone a Series VI adapter made for it- Tiffen. The Tiffen Series VI adapter for Canon 40mm is a #603. I'm lucky this one is marked 39.5mm, I'd never guessed there was a such size.

Three_Planars.jpgThreePlanars2.jpg
 
Regarding the Konishiroku Hexanon 5cm f1.9 LTM, I've collected a list of about 100 serial numbers with #3121021 being the lowest and #3124488 being the highest.

My hunch: Production started at 3121000 and went to 3124500, meaning about 3,500 were originally made.

If anyone has seen or owned an example of this lens outside that serial range, please let me know.

Only sharing this info here for posterity as I couldn't find any production info about this lens online.
 
Mine falls into the 22xx range- and has the smaller filter threads.
Any idea when the change from 39.5mm?
 
Missed this earlier. I don't have any of these three specific lenses. I do have the Chiyoko/Minolta 50/2 & a good Canon 50/1.4 though so perhaps the best one for me to watch for would be the Konishiroku/Konica Hexanon 5cm f1.9 LTM for this style of lens. As if I need another 50 ... (hmm... not _that_ expensive at Eprey... Oh, look there's a nice Summitar too... 😱 🤣 😎 )
 
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