Q on Ultron lenses

[wolan]

Hi,
apart from the famous Carl Zeiss Ultron 50mm f1.8 there are other two lenses from Voigtländer lenses with the same name. Is this a coincidence? Or does that define a specific lens design?

Thank you.

[calvin83]

I think it is similar to the name "Planar".

[wolan]

The peculiarity of the CZ Ultron is that it has a concave front element. But not sure about the Voigtländer lenses.

[visualopsins]

[tb_a]

The original Ultron was developed by A.W. Tronnier 1950 for Voigtlaender and was a 50mm/F2 lens with 6l/5g for the Voigtlaender Prominent RF camera. It was basically a modified Xenon lens which has been also designed by Tronnier for Schneider/Kreuznach already in 1937. As Zeiss took over Voigtlaender in the late 1950's they also made some of these lenses under Zeiss branding. The original design didn't have the concave front element. However, the lens design with the concave front element came also from Tronnier. It was introduced 1968 and built by Voigtlaender/Braunschweig but labelled as Carl Zeiss Ultron 50mm/F1.8 (7l/6g) for the Zeiss-Icon/Voigtlaender Icarex camera.

[paulhofseth]

Quite some time bfore the Zeiss Ikon camera company debacle, the foundation had bought the Vogtländer shares. Later they merged their sales efforts and finally merged the production companies with Voigtländer to become ZIV.

The Icarex was made by Voigtländer from july 1968 to december 1971 (first in bayonet mount, a bit over a year later in thread mount.) As a more expensive option than the Tessar, it came equipped with the concave front element, 7 lens element Ultron 50mm. Bayonet fit filter, sunshade. and lid.

Mr. Ottos thorough book lists all Zeiss camera versions. Mr. Thieles excellent lists of Zeiss prototypes will enlighten you on when the Ultrons were designed.

The later 50mms reverted to a more symmetrical "double Gauss" Planar type convex front element.

Names sell things, diagrams do not. Hence the ghost of this excellent 50mm lives on.

p.

[scsambrook]

Probably not really relevant to the original enquiry but the Leica screw mount Cosina-Voigtlander 35mm f1.7 Ultron lens also has a concave front element. Plus an aspheric surface as well.

[memetph]

[spiralcity]

As far as I know (and this is about the "Q" mark) It was used for grading lenses. Lenses intended for Western markets were subjected to high quality control standards. All lenses that passed the inspection where entitled to a special engraving. An intertwined 1- and -Q mark, known as a primarqualitat. Items with a slightly less quality were given a symbol of a triangle with a 1 or 2 in the center. This started in the 50's and lasted 2 decades.

As far as Voigtlander and Zeiss having a 50mm named the same really doesn't strike me as odd.

[tb_a]

[tb_a]

[memetph]

Looking at the optical schemes , the Planar/Color Ultron seems to be a descendant of the Zeiss Ultron.
The current Ultron 35 1.7 seems not to be a double gauss. The other Ultron of the VC range, the SL 40mm f2 is a double gauss ( 6/5) .

[tb_a]

[iangreenhalgh1]

Where did you get that 165lp/mm figure? Sounds like nonsense, 165 lines per mm would be more likely, which is 82.5 line pairs per mm, still extremely high.

[tb_a]

[iangreenhalgh1]

Well, I bet that site got it wrong as I have a hard time believing the Ultron can resolve anything like 165lp/mm, that would make it higher resolution than the very best lenses available today:

https://www.lensrentals.com/blog/2017/07/experiments-for-ultra-high-resolution-camera-sensors/

[kds315*]

[iangreenhalgh1]

[memetph]

I don't see any reason why at their best aperture and in the center the best lenses of the past would not match or approach the optical performances of the modern ones especially not measured using a digital sensor. Sensor's reflections are a problem for old lenses.
There are still some old designs in today's production and. stopped down. they can compete .

The purpose of those modern designed monsters is to achieve the best performance at wide aperture and all over the frame. They want also no CA in the corners and no LoCA at wide aperture ( APO). They need to use aspherical elements and want nevertheless a nice bokeh without onion rings . They need complex schemes but want good Tstop etc...

[iangreenhalgh1]

At what MTF value was the 165lp/mm measurement taken? I really do not think it was at a MTF of 1.0, which is where most measurements of resolution are made.

The old Color-Skopar was closer to being apochromatic than many lenses that are labelled 'APO' today, so yes, old lenses could be very highly corrected.

[paulhofseth]

Some features of newer optics, such as internal compensation for closer focus, obviously makes for greater flexibility, but not necessarily for better results if the intended use is for distant subjects (Leica R180\3.4) or for 1:10 (Zeiss 60\2,.

Some sacrifices may also have been made in order to make newer designs and groups of elements light enough for the motors of autofocus and internally stabilised devices to react fast.

Sample variation and robustness over time will of course also play a role.

As always, comparisons between old and new are most useful when done considering their actual use.

It would be interesting from a historical pont of view if Lensrentals ran measurements on older optics, but would perhaps not lead to much change in old lens usage, since some of the characteristics have pictorial value beyond lpmms.

p.

[visualopsins]

[scsambrook]

[iangreenhalgh1]

Yes, I think there has probably been an error at some point over time, that was my original point as the 165lp/mm figure just sounds wrong, how would you even measure such a resolution? If I remember rightly, Tech Pan tops out at about 150lp/mm.

[visualopsins]