|APO||The lens incorporates low dispersion elements to minimize chromatic aberrations and ensure excellent sharpness and contrast even at maximum aperture.|
|T*||The multi-layer coating is applied to the surface of lens elements. It boosts light transmission, ensures sharp and high contrast images, minimizes ghosting and flares.|
|Maximum format:||35mm full frame|
|Diagonal angle of view:||8.2° (35mm full frame)|
|Lens construction:||7 elements in 6 groups|
|Number of blades:|
|Closest focusing distance:||350 cm|
|Maximum diameter x Length:||Ø120 x 244 mm|
Design and Features
In general, the correction of longitudinal chromatic aberration in camera lenses is confined to the superimposition of the images for two colours of light. The aberrations occurring with all other colours produce the "secondary spectrum" which increases in proportion to the focal length. The secondary spectrum and the lateral chromatic aberration (appearing in the image field as colour fringes on contrasty edges) limit the optical performance of a telephoto lens made up of classical glass.
Apart from crystal materials, the modern fluophosphate types of glass also offer the possibility of drastically reducing residual achromatism. In the 300 mm TeIe-Apotessar® T* f/2.8 lens this glass type, with its extreme optical properties, has been used for two elements. The result is superior image quality. The pictures are extremely sharp and brilliant.
The name Apotessar indicates the excellent correction of chromatic aberration.
For focusing the Tele-Apotessar® T* lens, a group in the lens is moved (internal focusing). The advantages of this principle over the usual shift of the total system are easy to see: constant length of the lens and virtually constant location of the centre of gravity during focusing; improved ease of motion and operation of the focusing ring; the focusing helicoid has to move only a light group and hence does not have to withstand the pressure of the weight of the entire lens. Another point to note is that the image quality is still very good at minimum focusing distance.
2) On a tripod
|User Manual. English, Adobe PDF, 115 KB|