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Canon 2X EF Extender II Teleconverter (L Series Tele/Zoom Lenses)

Model #212437
  • $221.00

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New in box complete with manufacturer's USA warranty. Not previously owned or used.
Essentially new with no signs of use. “Open box.” In manufacturer's packaging with original accessories and instructions. 180-day warranty.
Barely used with virtually no traces of wear. Only the closest inspections will reveal slight use. Lens glass could contain light dust or debris. Excellent picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Lightly used with limited signs of wear. Exceptionally nice but may have slight wear on finish visible. Lens glass could contain light dust or debris. Excellent picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Noticeably used with average signs of wear. Shows moderate wear for the age of the item, with the possibility of blemishes and/or minimal dings. Lens glass may have average dust and zoom/focus ring tension may have slight looseness or tightness overall, but will not affect picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Frequently used with above-average wear. May have dents, dings, or finish loss. Lens glass may have small scratches, dust, and blemishes, and zoom/focus ring tension may have moderate looseness or tightness overall, but should not affect picture quality. Accessories usually not included, unless noted in listing. 180-day warranty.
Heavily used with extensive visible wear. Equipment is rough, with multiple impressions in the finish, excessive finish loss and brassing. Glass will have marks, fungus and/or heavy/cloudy haze which could affect picture quality. Accessories usually not included, unless noted in listing. Not covered under KEH warranty.
Non-functional or damaged. Equipment will not work. Usable for parts. Not covered under KEH warranty and non-returnable.
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$221.00
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Canon 2X EF Extender II: doubles focal length for L-series glass

Slip this between a compatible Canon L-series telephoto and your EF body and the math is immediate: a 400mm f/2.8 becomes an 800mm f/5.6, a 300mm f/4 becomes a 600mm f/8. The 2x magnification factor comes at the cost of 2 stops of maximum aperture, a trade that makes sense when you're working in good light and need reach that would otherwise require a lens costing several times more.

Compatibility is limited to Canon L-series telephoto and zoom lenses, which keeps the optical pairing tight. Canon engineered the II-series extenders alongside that glass, so autofocus communication, EXIF data, and image stabilization signals pass through without interruption. The bayonet fits the EF mount directly, no adapters needed.

For what it adds to your kit in reach and subtracted bulk, this extender earns its place in a working telephoto system.

Who It's For

Wildlife and sports photographers working with 300mm or 400mm L-series primes get the most direct benefit, turning a mid-range telephoto into something that can isolate distant subjects at 600mm or 800mm without adding a second heavy lens to the bag. Safari shooters on long trips where kit weight is a hard constraint will find the 2-stop aperture trade acceptable in daylight. Birders using the 100-400mm zoom gain meaningful reach at the long end for subjects that won't let you get close.

Key Features

  • 2x magnification factor for doubled focal length reach
  • Reduces maximum aperture by 2 stops
  • Canon L-series telephoto and zoom lens compatibility only
  • EF bayonet mount for direct attachment
  • Preserves autofocus communication without degradation
  • Full EXIF data and image stabilization signal transmission
  • No adapter required for EF camera bodies

FAQ

What lenses work with the Canon 2X EF Extender II?
Canon L-series telephoto and zoom lenses only. Canon designed the II-series extenders specifically for those optics, so autofocus and image stabilization function without compromise.
How much does the extender reduce maximum aperture?
2 stops. A 400mm f/2.8 drops to f/5.6 when the extender is mounted. In bright conditions, the trade-off is straightforward: doubled reach for reduced light gathering.
Does autofocus still work with this extender?
Yes. The EF bayonet passes autofocus signals directly to compatible Canon bodies without degradation. EXIF data and image stabilization signals transmit normally too.
Can I use this extender with non-L Canon telephoto lenses?
No. The II-series extenders are optimized for L-series glass only. Using them on other Canon telephoto lenses will result in autofocus errors and optical degradation.
What's the actual focal length multiplication?
Exactly 2x. A 300mm lens becomes 600mm; a 500mm becomes 1000mm. The magnification factor is precise across the L-series lineup.
Do I need an adapter to mount this to my EF camera body?
No. The extender mounts directly to the EF bayonet on your lens, then the lens attaches normally to your camera body. No adapters required.
Will this extender work with Canon RF-mount cameras?
No. This extender is EF mount only. Canon produces separate RF extenders for mirrorless systems.
SpecificationValue
MountCanon EF

This description was generated using AI based on KEH's internal product standards, product expertise, and knowing what customers care about most. While we strive for accuracy, details may vary by individual item.

Brand Name Canon
Focus Type Autofocus (lens motor)
Lens Mount Canon EF