Canon EF 70-300mm f/4-5.6 IS USM

Put this next to the EF 70-300mm f/4-5.6L IS USM and the gap is honest. The L is sharper at 300mm, weather sealed, focuses with a ring-type USM you can grab at any time, and costs two or three times as much. This one, the plain IS USM from 2005, gives you most of the reach for a fraction of the money, and for years it was the lens people actually bought when the L was out of budget. It replaced the wobbly old 75-300mm IS and felt like a genuine upgrade: quieter, steadier, sharper in the middle of the range.

The optics are fine until they are not. From 70mm to about 200mm, stopped down to f/8, it is a perfectly respectable lens, contrasty enough and sharp across most of the frame. Push to 300mm wide open at f/5.6 and it softens noticeably, with corners that smear and contrast that drops. Stop down to f/8 or f/11 and it tightens back up. That recovery is the entire reason to like the lens, so plan your shots around it. Bokeh at the long end is smooth enough for casual portraits, though the variable aperture means you are working at f/5.6 exactly when you want subject separation most.

The thing nobody warns you about is the focus motor. Despite the USM badge, this is a micromotor USM, not the ring-type drive in the L lenses, so there is no full-time manual override and autofocus hunts in low light. You can hear it work. For static subjects in good light it is a non-issue. For birds in flight or kids running at you in a gym, it lags. Image Stabilization, rated around three stops, is what keeps the lens usable; without it, handheld 300mm at the shutter speeds this aperture forces would smear most frames.

Who shoots it: travelers, casual wildlife and zoo shooters, parents at soccer games, anyone who wanted long reach without a backpack full of glass. People cross-shop it against the Tamron 70-300mm VC and the Sigma equivalents, and the Canon usually wins on autofocus consistency on Canon bodies even when the third parties match it optically. It is a daylight lens above all. Feed it sun and f/8 and it gives you results you would not expect from something this cheap.

One practical note. At 300mm and f/5.6 in fading light you are constantly fighting for shutter speed, and IS steadies the lens but not your subject. Meter for the actual light falling on what you are shooting rather than trusting the bright sky behind it, and let Zone Light Meter tell you honestly how far you have to open up or slow down. The 58mm front thread is small and cheap to filter, so a polarizer or ND for long daytime exposures costs almost nothing. Know where it falls apart, shoot inside those edges, and it earns its keep.