The SIGMA TELE CONVERTER is developed exclusively for the new lens lines. By mounting it in between a telephoto lens and a camera, the offered magnification of focal length of TC-1401 is 1.4 times and that of TC-2001 is 2 times respectively.
Both models incorporate SLD (Special Low Dispersion) glass elements that offer excellent aberration correction. It is exceptional for a lens accessory to use one of the best glass materials, yet this is because Sigma is seeking for the best image quality, and it is necessary to meet the new "SGV" standards.
It is suitable for professional use since its durable construction is dust and splash-proof. It is compact and light, and provides easy extension of focal range.

Features:

Incorporating SLD glass elements for better image quality.
TC-1401 incorporates 1 SLD (Special Low Dispersion) glass element, and TC-2001 carries 2. By minimizing chromatic aberration effectively, it has achieved very good optical performance, thus it is possible to maintain the optical quality of the original lens.

Compatible with lenses of large diameter.
Its power distribution is designed for lenses of large diameter. Without affecting the lens performance, it offers stable image quality until corners. The rich peripheral brightness enables shooting quality images at every focal length.

The durable dust and splash-proof construction is suitable for professional use.
It is dust and splash-proof, and designed for higher durability. SIGMA 150-600mm F5-6.3 GD OS HSM |Sports and other telephoto lenses are able to meet the demands that professional photographers would require in severe shooting conditions, such as in the rain.

AF is effective up to F8.
When the new SIGMA TELE CONVERTER is attached to cameras that are compatible with AF at F8, it is possible to shoot with AF.
* When shooting subjects with low contrast or luminosity value, focus may not be spot on the subject.

Evaluation with SIGMA's own MTF measuring system "A1"
We used to measure lens performance with an MTF measuring system using conventional sensors. However, we've now developed our own proprietary MTF (modulation transfer function) measuring system (A1) using 46-megapixel Foveon direct image sensors. Even previously undetectable high-frequency details are now within the scope of our quality control inspections. The SIGMA TELE CONVERTER TC-1401 and TC-2001 will all be checked using this "A1" before they are shipped.

SIGMA TELE CONVERTER TC-2001:

Lens Construction. 10 elements in 5 groups
Shooting Range and Shooting Ratio. 2.0 times of magnification from original lens
Dimensions (Diameter × Length). ?69.8mm × 48.9mm/2.7in. × 1.9in.
Weight. 290g/10.2oz.