When paired, the teleconverter and lens offer 210-840mm F6.3-9 zoom lens reach, with full autofocus functionality with most recent DSLR cameras.

This lens from Sigma's Contemporary range is lighter and more compact than the Sports version, and is more affordable too. It's available for Nikon, Canon and Sigma bodies and works with both full-frame and APS-C DSLRs.

I haven't fully used it, yet. I did try to capture an eagle and got nothing but blur. Perhaps operator error. Still working out the kinks.

A little while ago, we reviewed the mighty Sigma 150-600mm f/5-6.3 DG OS HSM | Sports - quite an impressive lens in terms of size and weight and despite its long zoom range, it's also pretty good.