Freeze frame: Alessandro Trovati's essential lens for skiing shoots

Alessandro's kitbag is equipped for photographing a broad range of sports in different styles. It includes Canon EOS-1D X Mark II bodies, and lenses ranging from the Canon EF 11-24mm f/4L USM to the Canon EF 600mm f/4L IS III USM. However, the one essential lens he always takes with him is the Canon EF 100-400mm f/4.5-5.6L IS II USM. He says it's good for many sports he shoots, including cycle racing, but is essential when shooting skiing, which is notoriously challenging to photograph.

Elite skiers travel over long, steep courses at speeds of up to 130km/h in the downhill competition, or move rapidly from side to side as they weave between gates in the slalom. Alessandro may be photographing close-ups of skiers before they set off, or action shots during the event when they're travelling at high speed or crossing the finish line.

"Sometimes I am 100 metres away from the subject, and for that situation I usually use the Canon EF 600mm f/4L IS III USM lens," says Alessandro. "But there are many situations where I don't want to use such a long lens. The Canon EF 100-400mm f/4.5-5.6L IS II USM is very good in the finish area, for example, because you can shoot the celebrations wide or close-up. I keep that lens on one of my EOS-1D X Mark II bodies all the time."

The aperture of f/4.5-5.6 means this lens is not as fast as some of Alessandro's other Canon lenses. However, the 4-stop Image Stabilizer greatly reduces camera shake and means he can shoot at shutter speeds as low as 1/8 sec if he wants to capture motion blur within an otherwise sharp image. He can also use the lens's Zoom Touch Adjustment ring to control the amount of resistance and make zooming faster when the situation is rapidly changing.

"I've used other zooms in the past, but I hand-hold my camera so I can react quickly and some of the longer zooms are too big and heavy," he explains. "Now I use only the Canon EF 100-400mm f/4.5-5.6L IS II USM, because it's so good. Focusing is fast and very sharp. You can shoot a lot of different pictures with this one lens, and it's so small and light it can be used in many different situations." At just 1,550g, the lens is comfortable to hand-hold, and its 193mm length means it doesn't take up too much storage space.

"The EF 100-400mm f/4.5-5.6L IS II USM is good for all sports when you need flexibility," says Alessandro. "And when I'm shooting fast action, when the subject is sometimes close and other times far away, this lens is the best solution for me."