Canon Canon EF 100-400mm f/4.5-5.6L IS USM Telephoto Review
The Canon 100-400mm L delivers pro-level image quality that still holds up, but its slow autofocus and lack of weather sealing show its age.
Overview
Look, the Canon EF 100-400mm f/4.5-5.6L is a classic for a reason. It's a workhorse telephoto zoom that delivers stunning image quality, landing in the 95th percentile for optics. The one thing you need to know? This lens is built for reach and sharpness, not for speed or low light. That f/4.5-5.6 aperture is a real limitation, but if you're shooting wildlife, sports, or landscapes in decent light, the pictures are incredible. Just don't expect to use it for portraits or anything in the dark.
Performance
The optical performance genuinely surprised me. For a lens this old, the sharpness is outstanding, especially when you consider it's a super-telephoto zoom. The two-mode image stabilizer, which sits in the 89th percentile, is a lifesaver for handheld shots at 400mm. What didn't surprise me was the autofocus. It's fine in good light, but that 47th percentile ranking tells the whole story. It hunts in low contrast and isn't the quietest. It gets the job done, but it's not fast or modern.
Pros & Cons
Pros
- Optical quality is phenomenal. Images are sharp and contrasty across the zoom range. 95th
- The image stabilization is super effective, letting you shoot handheld at surprisingly slow shutter speeds. 92th
- The 100-400mm range is incredibly versatile for wildlife, sports, and even some landscape work. 89th
- It's an L-series lens, so the fluorite and Super UD elements give you that pro-grade color and clarity.
Cons
- The autofocus is dated. It's noisy and can struggle to keep up with fast action. 13th
- The maximum aperture is slow. f/5.6 at 400mm means you need a lot of light or high ISOs. 20th
- It's not weather-sealed. For an 'L' lens, that's a pretty big omission if you shoot outdoors often. 21th
- At 1380g, it's a chonker. You'll feel it after a long day of hiking or shooting. 33th
Specifications
Full Specifications
Optics
| Type | Zoom |
| Focal Length Min | 100 |
| Focal Length Max | 400 |
| Elements | 17 |
| Groups | 14 |
Aperture
| Max Aperture | f/4.5 |
| Constant | Yes |
Build
| Mount | Canon EF |
| Weight | 1.4 kg / 3.0 lbs |
| Filter Thread | 77 |
AF & Stabilization
| AF Type | Autofocus |
| Stabilization | Yes |
Focus
| Min Focus Distance | 1800 |
| Max Magnification | 0.2x |
Value & Pricing
Prices are all over the map, from $1024 to $1555. That's a $531 spread, so shop around. At the lower end, it's a steal for the image quality you get. At the high end, you're paying a premium for the red ring on a lens that's missing key modern features like weather sealing and quiet AF. Stick to the lower price if you can find it.
vs Competition
The competitors listed are all fast prime lenses (35mm, 55mm f/1.8), which is weird. They're for completely different jobs. A real competitor would be something like the Sigma 150-600mm Contemporary. You get way more reach for similar money, but it's heavier and the optics aren't quite as crisp. Or, if you're on a modern Canon mirrorless body, the RF 100-400mm f/5.6-8 is lighter, cheaper, and has better AF, but you give up a full stop of light and that legendary L-series build. This Canon wins on pure optical pedigree.
Verdict
This is a specialist's lens. If you need a sharp, reliable telephoto zoom for daylight shooting and you're on a DSLR or using an adapter, it's still a fantastic choice, especially used. But if you need fast autofocus, weather sealing, or shoot in low light, look at modern mirrorless options. For the right shooter, it's a timeless tool.