I never planned on owning a 3.62 lbs./1640g lens, but the Canon EF 100mm-400mm f4.5-5.6L IS II USM is an amazing lens, situationally. For me, the lens serves two purposes. Taking photos of birds in my backyard and going to the zoo. If you are going for an ultralight setup this would be about the last lens you should consider buying.
It’s pretty much like carrying a brick around; my arm and neck hurt after four hours of lugging the lens around, but I ended up never taking it off the camera, because it’s a near perfect zoo lens. Ultimately, it’s lighter and less obtrusive than carrying a tripod and a lighter telephoto lens.The biggest highlight of the lens, to me, is image stabilization mode three. The image stabilization activates only when you engage the shutter; I’ve never had a reason to use mode one or two so far. I’ve even been able to handhold it at 1/6 of a second and still get a sharp image. Unless you are going to a zoo or on a safari, I don’t see a really good reason to travel with this lens. And on a safari, I’d probably rent a faster lens with longer reach.The f5.6 on the zoom end generally means you will have to raise your ISO to compensate. But, the noisy photo below still shows the detail still captured in this close crop. The mode three IS also allows you to leave the ISO low on some shots and instead just lower your shutter speed; just make sure the subject isn’t moving.For anyone who had the previous version, gone are the original version’s lack of sharpness and the push-pull zoom. It still has a lens barrel that extends with the ring zoom and some people may be concerned about dust getting inside the weather-sealing.The Canon EF 100mm-400mm f4.5-5.6L IS II USM is an extremely flexible lens and if you enjoy shooting wildlife it’s a great choice. It’s not really an ultralight choice, but if you need the versatility this lens offers for wildlife, it allows you to leave the tripod at home.