It is said that Zeiss' Tessar Eagle Eye is the sharpest masthead - no, it can be said that this is not the case at all. The Tessa lens was designed and put into production when the Zeiss factory was founded, because it performed relatively well compared to some lenses from other manufacturers at that time (note: at that time), it was easy to process for mass production, and its quality was stable, etc. It became famous due to its advantages and won the reputation of "Eagle Eye". But soon Zeiss went a step further and successfully designed and produced the Planar lens, which is still unbeatable to this day. Compared with Tiansai, it is... haha.

The structure of Tessa mirror is 4 elements in 3 groups, and the image is as sharp as a knife. But Tiansai also has its own limitations. One of them is that it is difficult to make a wide aperture. Generally speaking, the maximum aperture of most Tiansai heads you see is basically F3.5 or F4.5.

The Planar lens has a double Gaussian structure of 6 elements in 4 groups. The imaging is more delicate; the color reproduction is smoother; and the sense of three-dimensional space is very strong! And it can make a large aperture.

So the original poster may have noticed that some of the top versions of cameras are equipped with Planar type lenses!

For example: the ultimate model of Zeiss' 135 SLR brand "Contax"----Contax

The standard lens equipped with the SLR is Planar's 50mm or Snoona lens; Hasselblad's lens; Rolleiflex twin reflex mirrors---most of the primary lenses use Tessa lenses, while the higher versions use both. It's from Planar!

The structure of Tessa mirrors has long been perfected and matured, and has been mass-produced in the industry for a long time. Its structure is stable and rigorous, relatively easy to produce, low-cost, and of course the imaging quality is guaranteed. Very good value for money. Factories in various countries have imitations, which is one of the reasons why there are so many versions.

Why does he have so many versions? There are many reasons, and another more important reason is war. After World War II, Germany was divided into two. Due to its geographical location, many branches of Zeiss factories were also "scattered" in East Germany and West Germany. However, they quickly resumed production and each used the Carl Zeiss trademark... Only in East Germany Germany will have the outline image of its Zeiss factory building engraved on the cameras it leaves the factory; while West Germany will have other famous production places such as Stuttgart (Stuttgart) on the cameras.

The shape of the lens also has the symbols of various periods, such as what was later commonly known as: zebra head, pineapple head, etc.

In fact, as mentioned above, don’t believe too much and listen to the “hypocrisy” of some copycat writers on the Internet.

1. My body is Nikon's D700, but most of the ones I buy online have M42 interfaces. It is said to be for Leica bodies, and it is said that you can use M42 to N-mount adapter, but What should I do if I can only achieve focus within a few meters of distance? ----Purchase an adapter ring of better quality. We can discuss this issue later if necessary.

2. There are many versions of this lens, which version is better? (DDR, Zebra...) ----At that time, the lens coating technology was not yet perfect, so there were many single-layer coatings in the early days. Later, MC multi-layer coating is applied, so the color reproduction is also somewhat different.

In any case, these classic fixed focus lens structures such as Tiansai type, Planar type (Planar), Snoona (Snoona), etc. are all famous mirrors! They are still used in top cameras and have even been taken into space. These camera brands and lenses represent the highest quality! It's time-tested and recognized worldwide.