Canon EF 70-200mm f/4L IS USM

Wide open at f/4 this lens is already very close to its sweet spot. Most zooms ask you to stop down to f/5.6 before the frame snaps into focus. This one is sharp at f/4 across most of the image, corners catching up by f/5.6, and from there it holds that flat, even rendering edge to edge. That is exactly why people who own both the f/4 and the f/2.8 version keep the f/4 in the bag for daylight work.

It arrived in 2006 as the stabilized successor to the non-IS f/4L. The IS unit was rated for about four stops, strong for its day, and the whole package weighs around 760 grams. Set it next to the f/2.8 brick and the difference in your hand is immediate. Event shooters, travelers, and landscape photographers all gravitate to the f/4 for the same reason: it is the telephoto you actually want to carry past the first hour.

Rendering is clean and slightly cool, with Canon's typical L contrast. Bokeh at 200mm f/4 is smooth enough for tight portraits and gymnasium sports, though it is never going to dissolve a background the way the f/2.8 does. The circular aperture keeps out-of-focus highlights round rather than faceted. Flare is well controlled with the hood on; shoot it into a low sun without the hood and you will get some veiling, same as any telephoto with this many elements.

The honest weakness is the maximum aperture itself. f/4 is a stop and a half slower than the f/2.8 sibling, and indoors or at dusk that stop matters more than the four stops of IS can buy back, because IS does nothing for a moving subject. Shoot a dim wedding reception or indoor basketball and you will be pushing ISO where the f/2.8 owner is comfortable. For static subjects, landscapes, and outdoor portraits, you never notice.

Today it holds its place as a value pick on Canon's EF system. People cross-shop it against the f/2.8L IS (heavier, brighter, far pricier) and the third-party Tamron and Sigma 70-200 f/2.8 options. The f/4 wins on weight, sharpness wide open, and price on the used market, where it stays one of the more sensible L purchases going. Adapt it to an RF mirrorless body and it keeps working with full autofocus and IS.

On film bodies it covers the 35mm frame with a 67mm filter thread that makes ND grads and circular polarizers cheap to feed, useful since landscape at 200mm is where this lens shines. At that focal length you are usually isolating something against a brighter or darker field, so a spot reading off the subject in Zone Light Meter keeps it where you want it on the curve while the background falls where it falls.