EF400mm f/5.6L USM

EF400mm f/5.6L USM

This lightweight, compact 400mm super telephoto lens is highly portable, enabling the photographer to keep pace with even the most rapidly moving subjects in constantly changing shooting conditions. One Super UD lens element and one UD element combine to effectively control secondary spectrum. A double focus ring facilitates a variety of grips to suit various shooting situations. A pull-out hood, switchable focus range, and detachable ring-type tripod mount contribute to outstanding operability.


Angle of View
(horizontal, vertical, diagonal)
5°10’/ 3°30’/ 6°10’
No. of Diaphragm Blades 8
Closest Focusing Distance 3.5m
Maximum Magnification 0.12x
Water/dust Resistance -
Filter Size 77mm
Max. Diameter x Length Ø90 × 256.5mm
Weight Approx. 1,250g
Extension Tube EF12 II 0.16−0.03x
Extension Tube EF25 II 0.21−0.07x
Lens Cap E-77U / E-77 II
Lens Hood Built-in
Lens Pouch/Case LZ1132

  • Super UD element
  • UD element

MTF Characteristics

Spatial frequency Maximum aperture
10 lines/mm
30 lines/mm
How to read
MTF characteristics

Spatial frequency Maximum aperture
10 lines/mm
30 lines/mm

The more the S and M curves are in line, the more natural the blurred image becomes.

Modulation Transfer Function, or MTF, is a method of evaluating lens performance using contrast reproduction ratio. When evaluating the electrical characteristics of audio equipment, one important measure of performance is frequency response. This indicates the fidelity of the reproduced sound with respect to the source sound as it passes through the microphone, recording and playback circuits, and finally the speakers. When the reproduction is accurate, the equipment is classified as “hi-fi,” or “high fidelity.”
In the same way, when a lens is viewed as a transmission system for optical signals, measuring the frequency response of the optical system reveals whether the optical signal is transmitted faithfully. For a lens, the equivalent of frequency is “spatial frequency,” which indicates how many patterns, or cycles, of changes in sinusoidal density are present in a 1 mm width. Accordingly, the unit of spatial frequency is lines per mm, as opposed to Hz in electrical systems.

The MTF characteristics shown on this website are 10 lines/mm and 30 lines/mm, where the horizontal axis indicates image height (the distance on a diagonal line from the center of the image, in mm) with the image center set to 0, and the vertical axis indicates contrast. The closer the 10-line/mm curve is to 1, the better the contrast and clarity of the lens; the closer the 30-line/mm curve is to 1, the better the resolving power and sharpness of the lens. Although a good balance between both of these is important for a lens to be sharp and clear, a lens is generally said to offer excellent image quality if the 10-line/mm curve is greater than 0.8, or satisfactory image quality if greater than 0.6.

Resolving power and contrast are both good

Contrast is good; resolving power is poor

Resolving power is good; contrast is poor