Conclusion

There aren't too many telephoto zoom lenses for Sony Alpha cameras, so it's great to see Sigma joining the party with the launch of the 100-400mm F5-6.3 DG DN OS.

Commendably, it's not just an exact copy of the DSLR version, with an extra AFL button, a closer focusing distance at 100mm, and a new optional tripod collar.

On the negative side, it seemed to be more prone to hunting during focusing than the DSLR version, no longer has a distance scale, and you have to pay extra for that nigh-on-essential tripod collar.

Thankfully, the Sigma 100-400mm F5-6.3 DG DN OS offers very good image quality throughout its versatile focal range, whilst being light and compact enough to make it suitable for hand-holding.

Optically, though, it's no match for the admittedly pricier and heavier Sony FE 100-400mm F4.5–5.6 GM OSS, which is probably the telephoto zoom lens that Sony users most aspire to.

The Sigma 100-400mm F5-6.3 DG DN OS is still tack-sharp at both the centre and edges of the frame when stopped down by one-stop at all the focal lengths, with the exception of 400mm. Obvious vignetting at wide-open apertures is the only other real optical issue of note, and this can be easily corrected in post-production.

Build quality is very good, with the sober all-black design adding to the high-quality feel and the dust/splash-proof construction adding some peace of mind, plus there's a decent lens hood included, although the lack of a case/soft bag and even more importantly that all-important tripod collar are clearly concessions made to hit the aggressive price-point.

Overall, the Sigma 100-400mm F5-6.3 DG DN OS is a welcome addition to the rather sparse range of Sony full-frame telephoto lenses, especially priced at £899 / $949. You may have to also budget for the TS-111 tripod collar, but at least Sigma have seen fit to offer the option on this version of the lens.

If you're in the market for a versatile telephoto zoom that won't break the bank, then this new offering from Sigma should be at the top of your list.

Ratings (out of 5)
Design	4.5
Features	4.5
Ease-of-use	4
Image quality	4
Value for money	4.5