Sigma 879956 1.4x Teleconverter TC-1401

The Sigma 1.4x Teleconverter TC-1401 is a purpose-built optical accessory that multiplies the focal length of compatible Sigma telephoto lenses by a factor of 1.4. This means a 150-600mm lens effectively becomes a 210-840mm lens, giving wildlife, sports, and aviation photographers significantly more reach without carrying a second, longer lens. The tradeoff is a one-stop loss of light — an inherent characteristic of 1.4x teleconverters — which shifts an f/5.6 lens to f/8 and an f/6.3 lens to f/9. The TC-1401 preserves autofocus functionality at effective apertures up to f/8 on compatible camera bodies, which is critical for tracking fast-moving subjects.

Build quality is a standout feature of the TC-1401. Its dust and splash-proof construction matches the weather sealing found on Sigma's Sport and Contemporary lens lines, ensuring that the connection between lens and body remains protected in adverse conditions. The compact form factor adds minimal length and weight to your setup, making it practical to keep in a camera bag as an always-available reach extender. It is worth noting that the TC-1401 is engineered exclusively for Sigma mount lenses — it will not physically or electronically couple with lenses from Canon, Nikon, Tamron, or other manufacturers.