Thank you for purchasing a Canon product.
EF40mm f/2.8 STM is a compact, lightweight, low-proﬁle high quality standard
single focal point lens.
“STM” stands for Stepping Motor.
Do not look at the sun or a bright light source through the lens or
camera. Doing so could result in loss of vision.
Looking at the sun directly through the lens is especially hazardous.
Whether it is attached to the camera or not, do not leave the lens under
the sun without the lens cap attached.
This is to prevent the lens from
concentrating the sun’s rays, which could cause a ﬁre.
If the lens is taken from a cold environment into a warm one,
condensation may develop on the lens surface and internal parts.
prevent condensation in this case, ﬁrst put the lens into an airtight plastic
bag before taking it from a cold to warm environment. Then take out the lens
after it has warmed gradually. Do the same when taking the lens from a warm
environment into a cold one.
Do not leave the lens in excessive heat such as in a car in direct sunlight.
High temperatures can cause the lens to malfunction.
Cautions during shooting
This lens uses a stepping motor to drive the focusing lens (the lens that has
the job of focusing the shot).
1. Cautions when the power is off
Since the motor does not operate when the camera is off or has been
turned by the auto power-off function, take note of the following points.
2. Cautions when the lens is in sleep mode
This lens has a sleep mode separate from the camera auto power-off
function for saving power when the lens has not been operated for a period
Since the motor does not operate when the lens is in sleep mode, even if
the camera is turned on, take note of the following points.
To retract the lens if extended, keep the lens attached to the camera, and
then autofocus at inﬁnity or turn the focusing ring.
To shoot with this lens attached on an EOS-1D Mark IV, update the EOS-
1D Mark IV ﬁrmware to version 1.1.1 or later. Updating to this ﬁrmware will
optimize exposure accuracy.
When using an EOS ﬁlm camera, the action of the focus may slow down if
the battery is low on power or when the ambient temperature is low.
About the AF frame selection
High accuracy cross (+) detection can be used in the center AF frame and
horizontal line detection can be used in the frames other than the center AF
frame for the following cameras.
EOS-1Ds Mark III, EOS-1Ds Mark II, EOS-1Ds, EOS-1D Mark IV,
EOS-1D Mark III, EOS-1D Mark II N, EOS-1D Mark II, EOS-1D, EOS-1V,
Conventions used in this instruction
Warning to prevent lens or camera malfunction or damage.
Supplementary notes on using the lens and taking pictures.
1. Mounting and Detaching the Lens
See your camera’s instructions for details on mounting and detaching the
After detaching the lens, place the lens with the rear end up to prevent
the lens surface and contacts from getting scratched.
If the contacts get soiled, scratched, or have ﬁngerprints on them,
corrosion or faulty connections can result. The camera and lens may not
If the contacts get soiled or have ﬁngerprints on them, clean them with a
If you remove the lens, cover it with the dust cap. To attach it properly,
align the lens mount index and the
index of the dust cap, and turn
. To remove it, reverse the order.
2. Setting the Focus Mode
To shoot in autofocus (AF) mode, set the focus mode switch to AF
To shoot in manual focus (MF) mode, set the focus mode switch to MF, and turn
the focusing ring to set the focus
When the camera AF mode is ONE SHOT AF, focus manually by pressing
the shutter button halfway and turning the focusing ring. (Full-time manual
When turning the focusing ring suddenly, the focus adjustment may be
The focus cannot be adjusted in MF mode while the camera is off.
Do not touch the front rotating parts of the lens while autofocus is active.
Focus mode switch
Lens mount index
EF40mm f/2.8 STM