Canon 400mm f/2.8 L IS USM EF-Mount Lens {Gel}

Canon's proven 400mm f/2.8L: the telephoto benchmark

At 400mm and f/2.8, this lens does one thing with no compromise: it puts a subject at distance in front of a completely separated background while keeping autofocus response fast enough for erratic movement. The ring-type USM motor drives internal focusing quietly and quickly, and full-time manual override means you can fine-tune without switching modes. The 8-blade diaphragm produces smooth out-of-focus rendering at wide apertures, and the IS system buys back stops when you need to handhold or shoot from an unstable position.

The 17-element, 13-group optical formula has held up as a reference design, used on Canon EOS bodies from film to full-frame digital without modification. Weather sealing and a magnesium alloy barrel make it field-durable for the kind of long days this focal length gets used on. The integrated tripod collar is essential at 5,370g, shooting handheld is possible but the collar keeps a monopod or tripod setup balanced. A 52mm rear gel filter slot handles polarizers and ND filters without front filtration hardware on a lens this diameter.

Native to Canon EF, it also adapts cleanly to Canon RF, Sony E, Nikon Z, and L-Mount bodies. For any shooter already working the Canon ecosystem, this is the lens that defines what 400mm f/2.8 means in practice.

Who It's For

Wildlife photographers working in low light or dawn/dusk windows get f/2.8 light-gathering at 400mm, which no zoom can match at this focal length. Sports photographers covering sidelines or indoor track need the USM speed and IS to lock focus on athletes in motion without blur from camera movement. Photojournalists on long-lens assignments rely on the weather sealing and magnesium construction for all-day outdoor work. Portrait photographers willing to work at distance use 400mm f/2.8 specifically for the extreme subject isolation it produces at minimum focus.

Key Features

• 400mm prime telephoto with f/2.8 maximum aperture
• Ring-type USM autofocus with full-time manual focus override
• Image stabilization for handheld and monopod shooting
• 17-element, 13-group optical design unchanged since 1999
• 8-blade diaphragm for smooth out-of-focus rendering
• Weather-sealed magnesium alloy barrel with integrated tripod collar
• Focuses internally to 3.0m minimum distance
• 52mm rear gel filter slot for polarizers and ND filters

FAQ

What autofocus motor does this lens use?

Ring-type USM (ultrasonic motor) that drives internal focusing elements. It's quiet, quick, and won't hunt when tracking erratic movement - the motor design has stayed consistent across the 27-year production run because it works.

Can you manually focus while autofocus is active?

Yes. Full-time manual override means you rotate the focus ring anytime without switching modes or disengaging AF. Dial in fine-tuning on a subject already locked, or catch focus shifts on the fly.

What's the maximum aperture and how does the 8-blade diaphragm perform?

f/2.8 maximum. The 8-blade design produces smooth, rounded bokeh at wide apertures - noticeable separation on subjects at distance, especially against busy backgrounds. That's the entire point at this focal length.

Is there image stabilization, and how many stops does it add?

Yes, the IS system is built in. It's not a replacement for tripod technique at 400mm, but it buys you handheld flexibility and steadier framing from monopod or unstable shooting positions. Exact stop improvement varies by body generation.

What about weather sealing and build materials?

Magnesium alloy barrel with metal mount and full weather sealing. Designed for field work on long shooting days. At 5,370g, it needs the integrated tripod collar for balanced support - the collar is essential, not optional.

Does it work on modern mirrorless cameras?

Native to Canon EF. Adapts cleanly to Canon RF, Sony E, Nikon Z, and L-Mount with appropriate Canon adapter. AF and IS function normally on adapted bodies.

What filtration options are available?

52mm rear gel filter slot built in for polarizers and ND filters. No front filter threads - that diameter would be impractical. The rear slot handles common optical adjustments without additional hardware.