Datasheet

1
0.5
0
0.4
0.3
0.2
0.1
0.6
0.7
0.8
0.9
0 5 10 15 20
Performance
Distance from centre of frame(mm)
How to read MTF charts
An MTF (Modulation Transfer
Function) chart indicates the
resolution and contrast of a lens
from the centre to the corner of an
image both at the lens’ maximum
aperture and at f/8. The graph is
calculated from the lens’ ability to
reproduce sets of extremely fine lines
both parallel to the image diagonal
(Sagittal) and perpendicular to the
image diagonal (Meridional). One
set of lines is spaced with 10 lines
per millimetre (lpmm) and is used
to indicate contrast. A second set,
at 30 lines per millimetre, indicates
resolution (sharpness).
A Canon MTF chart is made up
of 8 graph lines in two colours.
The 4 black lines represent the lens’
performance at maximum aperture
while the 4 blue lines indicate
performance at f/8. Thick lines show
contrast (10 lpmm) and thin lines
resolution (30 lpmm). The lines
representing sagittal detail are shown
as solid lines. The lines representing
meridional detail are shown dashed.
For zoom lenses, charts are provided
for both the minimum and maximum
focal lengths.
The perfect lens would show both
solid and dashed lines running
horizontally across the top of the
chart – in other words, showing
100% accuracy throughout the frame.
In practice no such lens exists, so you
will see some amount of variance
with even the very best lenses on
the market.
Spatial
frequency
10 lines/mm
30 lines/mm
Maximum aperture f/8
S M S M
The more the S and M curves are in line, the more natural the
blurred image becomes
3
4
1
2
1 Contrast lines (thick lines) above 0.8 indicate superior contrast
2 Resolution lines (thin lines) above 0.6 indicate good sharpness
3 Lenses that demonstrate good edge performance have
almost horizontal lines
4 The closer the Sagittal and Meridional lines are together,
the more natural the blurred parts of an image appear
Other lens codes
DO Uses Diffractive
Optical elements
EF–S Designed for cameras
with an EF–S lens mount
MP–E or Macro Designed
for Macro photography
II or III Lens version
Lenses are sometimes
replaced with
improved models
Making sense of lens names
Each EF lens is identified by a series of codes which provide important
information about its characteristics.
100mm
The focal length
of the lens. A range
of values indicates
the maximum and
minimum focal lengths
of a zoom lens.
f/2.8
The maximum aperture
of the lens, expressed
as an F-stop. The smaller
the F-stop, the wider
the maximum aperture.
A range of values
indicates the aperture
at either end of the
zoom range.
L
Indicates a professional
L-series lens – the
ultimate in image
quality, durability
and performance.
IS
Indicates that the lens
uses an Image Stabilizer
to correct for unwanted
camera shake. IS allows
shooting at up to five
stops slower than would
otherwise be possible.
Dependant on the lens.
USM
Refers to Ultra Sonic
Motor. Found in many
Canon lenses, the USM
drives fast, silent and
accurate auto-focusing.
EF 100mm f/2.8L Macro IS USM
Key to icons
?
i
1
?
i
1
?
i
1
The symbols below are a quick
reference guide to help you
choose your lens based on the
types of photography you do.
Good for General Use
Good for Close Up
Good for Portraits
Good for Sports
Good for Indoor Sports
Good for Wildlife
Good for Landscapes
Good for Products
Good for Architecture
Good for Interiors
Good for Travel
Good for Weddings
Good for Reportage
Glossary
Tip
Information