Tessar, Sonnar, Sumicron, Plannar?????

[Rol_Lei Nut]

Zeiss Biogon and Distogon=wide angle, Planar=normal & Sonnar=telephoto.

Again, it's unfortunately not that simple.

The Rollei 35S had a 40mm f/2.8 Sonnar which is neither a telephoto nor especially fast. Also the classic 50mm f/2.0 Sonnar was no telephoto.

The 85mm f/1.4 Planar isn't exactly a normal.

[Q.G.]

A Tessar is a triplet in which one lens has been replaced by a cemented doublet. Typically twice the standard lens focal lenght. An old and popular design, but really not the best.

A Sonnar is a lens typically having a low number of rather thick elements. Makes very good lenses, from standard to (mostly) medium long focal length lenses.

A Planar is a double-Gauss type lens. Very good all round performance. Made in the standard to long standard focal length range.

A Biogon is a similar design, but with more glass and made for large angles of view.
Performance is (almost) on par with the Planars.

A Distagon is a reversed tele-photo, a.k.a. retrofocus construction.
A Retrofocus (the name of a lens made by Angenieux, who first made such a thing) lens makes using short focal lengths on reflex cameras possible, yet are not quite as good as non-retrofocus lenses (the distortion in particular is not as good).

[Fred De Van]

Where can I learn about the difference in all of these lens classifications? I have no idea what these classifications mean.

To get a correct answer find a book called Optics, the technique of definition, by Arthur Cox. Every answer so far are, at least in part, incorrect.

[stradibarrius]

I found this on the Zeiss web site;
The ‘C’ designation in the C Sonnar T* 1,5/50 ZM name means both ‘compact’ and ‘classic’. The lens design and aperture geometry reflect its predecessor from the 1930s, the Sonnar 1,5/50, which was the fastest standard lens of its time. The excellent flare control inherent of the Sonnar lens design is further optimized with the ZEISS T* anti-reflection coating.

The Planar® lens is the most successful camera lens design ever created. This nearly symmetrical layout provides the lens designer with numerous means to correct aberrations extraordinarily well, even for wide open apertures. The ideal basis for high-performance lenses with great color correction, high speed, flat image plane (this is where the name comes from)

[Q.G.]

Every answer so far are, at least in part, incorrect.

Now there's a challence: point out the incorrect bits and correct them.

[stradibarrius]

I really asked the question to try to distinguish between lenses that are great performers from those that are poor.
Personally I am not interested in optical formulas and the math that goes into the design. I am more interested in when choosing between the lenses which is the first choice, second and so on.

As with many thing in photography sometimes the performance can be very slight but the price difference can be great.

[Rol_Lei Nut]

I really asked the question to try to distinguish between lenses that are great performers from those that are poor.

Well, what do you mean by "great" and "poor" performance?

A lens ideally suited for one purpose or subject might be far less suited for another.

Just basing it on the scheme name isn't very useful: Some of these designs have been around for over a century and their various characteristics have changed greatly over time.

[Q.G.]

A lens ideally suited for one purpose or subject might be far less suited for another.

Indeed.
That's why there are different lens types, with different lens type names ...

Just basing it on the scheme name isn't very useful: Some of these designs have been around for over a century and their various characteristics have changed greatly over time.

Yes and no.
While there indeed is a large quality spread 'within' a particular lens type, i wouldn't, for instance, pick a Distagon to do close-up photography.
Though limited for the reasons you mention, knowing what design family is behind a lens design family name does have its use.

[Fred De Van]

Now there's a challence: point out the incorrect bits and correct them.

In order to do that correctly, I would have to write the book which Arthur Cox has already written.

[ntenny]

I really asked the question to try to distinguish between lenses that are great performers from those that are poor.
Personally I am not interested in optical formulas and the math that goes into the design. I am more interested in when choosing between the lenses which is the first choice, second and so on.

I think the only way to answer *that* question is through your own experience. Quality is so thoroughly subjective, and our vocabulary for talking in lay terms about optical properties is so limited, that it's hard to see what could be said about lenses that would help you in these terms.

For what it's worth, here's how my brain organises lenses: The most basic reasonably modern lens is a triplet, which occurs in a million different brand names with essentially the same design. Novar, Triotar, Cassar, Trinar, Vaskar...

Triplets have the basic problem that away from the centre of the image, especially wide open, they tend to go soft and vignette. Hence the Tessar design and its close kin, which add a fourth glass element to reduce these problems. Again, in addition to the Tessar itself (which was a Zeiss trade name), there are a bunch of essentially similar designs; Xenar, Skopar, most or all of the Russian "Industar-nn" lenses, etc. Unfortunately many of the same names have also been used for lenses of different (often *very* different) designs, so the name per se isn't a reliable guide---you have to have some context in order to know what lenses the name was being used for in a particular time, place, and setting. (The Lens Collector's Vade Mecum is helpful for keeping track of these changes; it's imperfect but it's still a helluva reference.)

I believe some of the Leitz Elmars are Tessar designs.

You can, of course, keep adding elements and changing configurations in an effort to climb the diminishing-returns curve; Tessars are a lot better at the edges than triplets, but there's still room for improvement. The canonical "next step up" from the Tessar is the Planar, which adds some more glass, is sharper, vignettes less, and costs more. Schneider's Xenotar, mostly seen on Rolleiflexen, is similar. However, things get complicated here because the number of reasonable combinations grows as you add more elements; five or six elements is enough to create a lot of design flexibility, and except for a few well-known lenses (Planar, Heliar...), it becomes difficult to use the name as a guide.

Also, it seems like the tendency to use the name as an indicator of the design went out of vogue sometime in the latter half of the last century, leading to things like the Olympus convention where a prefixed letter tells you how many elements there are ("D.Zuiko"==4 elements, "E.Zuiko"==5 elements, &c.).

And then Leica lenses are a language unto themselves, with the name sometimes reflecting the design, sometimes the maximum aperture, sometimes apparently just a whim. I've never attempted to understand this part of the lens world, as I don't ever expect to be able to afford an actual Leitz lens.

Finally, there are some outliers like the Zeiss Biogon (and its Ukrainian clone the Jupiter-12), which don't fit easily into any particular schema and just sort of have to be treated as individuals.

But as far as what you *like*---that part you gotta take up with yourself. Some people really like lenses to be as close to technically perfect as possible and will happily spend the GDP of a small country for a 237-element monster made of unobtainium-tinged glass hand-polished by elves enslaved in the forges of Mordor, or whatever---others find the theoretically "best" lenses to have a sort of antiseptic look and actually prefer using ones that on paper are "inferior".

-NT