The Online Photographer

It's a special kind of Tessar. Here is its MTF performance—but this looks worse than it is, because it shows measurements for the very stringent standards of 20, 40, and 80 lp/mm, whereas most MTF charts you'll come across are for 10, 20, and 40 or even 5, 10, and 30 lp/mm. The larger the structures they're measuring (i.e., the lower the number of lp/mm or lines per millimeter), the better the measurements look. If you're up on how to read an MTF chart, you might already have guessed what you're looking at before you read the caption:

Performance data of a Tessar lens for a mobile phone camera measures [sic] with 20, 40 and 80 Lp/mm. It is better than the best 35mm lenses—but only for a very small image.

The chart and caption come from a ZEISS white paper on Tessar-types written by H.H. Nasse and published by Carl Zeiss AG Camera Lens Division in March of 2011. The paper also says:

The name Tessar lives on in our state-of-the-art miniature lenses for camera modules in the mobile phones of our partner Nokia. The similarity to the classic Tessar is that four lens elements are usually used. The small size is also a related feature and an absolute must for the small volume [that is, size —Ed.] of a pocket sized device [the phone]. However, the functionality of this tiny lens no longer has anything to do with the original Tessar patent. It is usually designed with four lens elements with aspheric surfaces. The resolution of these small and economical optics is far superior to the best 35mm lenses—but this is due to the short focal length and the small image field.

At the link, look at the remarkable picture with the matchstick in it. Superimposed on a FF sensor, for scale, it shows a cutaway of a Zeiss/Nokia Tessar phone camera lens, in which you can see the extreme and bizarre asphericity of the elements. Talk about mustache curves!

In comparison, here's the MFT chart of the Leica 43mm in the Q3-43 that Ken extolled in yesterday's post, at ƒ/2.8:

Looks better at first glance, doesn't it? But no. Don't get me wrong, it's truly awesome for a FF lens (especially in the extreme corners), but it's nowhere near the Zeiss Nokia Tessar because the frequencies represented here are 5, 10, 20, and 40 lp/mm! That means the lowest set of lines (solid, sagittal; dotted, tangential, a.k.a. meridional) on this chart are for the same structures as the middle line in the Zeiss/Nokia chart. No contest. By the way, I like an MTF chart that gives data for large structures, i.e. 5 and 10 lp/mm. That predicts both contrast and bokeh, which in the case of this Leica lens should be very good indeed.

So it's a bit of a trick answer to the question. But it's kinda neat that no matter what fancy FF lens you might have in your bag, the best lens you have is most likely in your pocket.

Mike

P.S. I might also add that as a general rule, lenses designed for less coverage measure better than lenses with more coverage. For film, 35mm lenses measure better than medium format lenses, which measure better than sheet film lenses. The larger formats make up, or more than make up, the image-quality deficit by requiring less enlargement—an 8x10-inch print from a 35mm negative requires enlargement of 10 diameters, whereas an 8x10-inch print from a 4x5 nagative requires enlargement of only two diameters. So it stands to reason that lenses designed to cover the much smaller typical sensor size for 2011 mobile phones would be better still, and this is what Zeiss confirms in its white paper. The 2011-era iPhone 4s, as an example, had a 1/3.2-inch sensor that was 4.5x3.4mm in size. Current iPhone sensors are considerably larger.

This isn't a hard-and-fast rule; spy satellite lenses (which fell under my father's purview when he was a Director of NASA in the 1970s—I got to see one of those lenses once) covered 10x10", and you can bet they resolved better than consumer camera lenses. Then again, those lenses cost $1,500,000 in inflation-adjusted dollars ($250,000 in 1975).

Another point of interest: I think I heard this from an official of an institution closely identified with Eastman Kodak, but I won't name or describe him to avoid embarrassing him if my memory is off. However, I believe I was told that Eastman Kodak developed, and once owned, the patents to mass-producing tiny press-moulded aspheric elements. But there was at the time no application for such lens elements, and the company couldn't figure out how to make money from them, so, assuming the technology was useless, they essentially gave the patents away. Today there are several such tiny aspheres in every mobile phone camera module.

Original contents copyright 2025 by Michael C. Johnston and/or the bylined author. All Rights Reserved. Links in this post may be to our affiliates; sales through affiliate links may benefit this site. As an Amazon Associate I earn from qualifying purchases. (To see all the comments, click on the "Comments" link below or on the title of this post.)

Featured Comments from:

Stephen Cowdery: "I noticed this phenomenon of the incredible resolution of small-format lenses with my Pentax Q7 and adapted larger-format lenses. With the exception of macro lenses, even the best bigger lenses couldn't compare with the native ones for the Q7."

Ed note: The Q7 was an interchangeable-lens digicam with a 1/1.7-inch type sensor 7.44 x 5.58mm in size.

Geoff Wittig: "I can confirm the Kodak press-molded aspheric element tale. One of my patients back in the day was a Kodak engineer who worked on the project. His team was flabbergasted that Kodak didn't exploit the idea but just threw it away since they couldn't comprehend how to get the kind of profit margins on it they were making from film. And within a couple of years such elements were in every CD/DVD player on the planet."