Canon EF300mm f/2.8L IS II USM Instructions Manual page 20

16. Extenders (Sold Separately)
Lens specifications when using extender EF1.4× II/III or EF2× II/III are as follows.
Focal length (mm)
Aperture
Diagonal
Vertical
Angle of view
Horizontal
Maximum magnification (×)
Attach the extender to the lens, and then attach the lens to the camera. To remove it, reverse the order.
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Errors may occur if you attach the extender to the camera first.
When shooting with EOS A2/A2E/5 fitted with either the EF300mm f/2.8L IS II USM or EF400mm f/2.8L IS
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II USM, use –0.5 step exposure compensation when using extender EF1.4× II, and use –1 step exposure
when using extender EF2× II.
Extenders cannot be used more than one at a time.
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AF is possible with extender EF1.4× II/III or EF2× II/III.
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When an extender is attached, the AF speed will become slower to retain proper control.
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EF300mm f/2.8L IS II USM
EF1.4× II/III EF2× II/III
420 600
f/4 – 45 f/5.6 – 64
5° 55' 4° 10'
3° 15' 2° 20'
4° 55' 3° 30'
0.25 0.36
EF400mm f/2.8L IS II USM
EF1.4× II/III EF2× II/III
560 800
f/4 – 45 f/5.6 – 64
4° 25' 3° 5'
2° 25' 1° 40'
3° 40' 2° 35'
0.25 0.35
ENG-19