The SIGMA 15-30mm f/3.5-4.5 DG IF is a wide-angle lens produced since 2001, suitable for FF and APSC format cameras. The focusing is automatic and takes place via a non-ultrasonic AF motor which is quite noisy, there is no image stabilization. The lens hood is incorporated and there is a slot for inserting gelatin filters. The shooting angle is 110 degrees with the 15mm focal length, while it drops to 71.5 degrees with the 30mm focal length; The minimum focusing distance is 30 centimetres. Weight and dimensions are above average but this does not cause the camera to be unbalanced, the materials are of good quality and give resistance and durability to the lens. The images taken are quite sharp and have faithful colours. At a 15mm focal length there is a significant distortion which decreases, until it almost completely disappears, at a 30mm focal length. Aberrations are also present but do not constitute an insurmountable problem as, like distortions, they are totally manageable in PP. The SIGMA 15-30mm f/3.5-4.5 DG IF is a lens with not excellent performance, it can be useful as a support lens but not to be used as a main one. It can be used by both professional and amateur photographers, it is very easy to use and is one of the few wide angle cameras to have autofocus. The cost is competitive but considering that it was put on the market a few years ago, there is a more than good chance of finding it used and thus managing to save money. It can be an excellent idea to increase a photographic kit.