Sigma CAN 35MM User Manual
Lens Compatibility with Digital SLR Cameras
CAN 35MM SLR LENSES BE USED ON DIGITAL CAMERAS?
In most cases, the answer is yes. If you have a lens for a fairly recent 35mm SLR camera, it can be used on a
new digital SLR from the same maker. (See the information below under the various camera brands for specific
details about using existing lenses on new cameras.) If the 35mm camera lens produces good, sharp, contrasty
images on film, it will produce good digital photos, too. One big difference is the angle of view. The imaging sensor in most digital cameras is smaller than 35mm film, measuring about 23 x 16mm. Therefore, wide-angle lenses for 35mm camera are not as wide when used on a digital camera, but telephoto lenses are stronger. With
35mm cameras, a 50mm lens is the “normal” focal length that gives you about the same view as the human
eye. Below 50mm, the view gets wider, above 50mm it becomes telephoto and draws the subject in closer. For
digital cameras, this “normal” focal length is about 32mm, so an old 50mm lens from your 35mm camera will be
a short telephoto (equal to 80mm) when used on a digital. An 18-200mm zoom lens for a digital camera has
about the same wide coverage and telephoto magnifying power as a 28-300mm lens on a 35mm camera. To
convert the equivalent view of a 35mm lens when used on a digital camera, multiply by 1.6X.
A few high-end digital cameras, such as the Canon EOS 1Ds and EOS 5D have full-frame sensors. Since these
sensors match the 24mm x 36mm size of 35mm film, there is no conversion factor when they are used with
35mm lenses.
LENS CONVERSION FOR VARIOUS CAMERA FORMATS
AOV = angle of view 6x6cm = 2-1/4 x 2-1/4" format on 120 film
DIGITAL-ONLY LENSES
Since the future of SLR photography is digital and since most digital cameras have sensors that are smaller
than 35mm film, manufacturers are making digital-only lenses. The primary difference is the reduced area of
coverage provided by digital-only lenses. These lenses have the same mounting style as 35mm format lenses
and they can be mounted on 35mm camera bodies (except Canon EF-S lenses), but they will not cover the full
image size. This causes vignetting around the edges of the 35mm image, especially at the widest end of the
lens zoom range.
Extreme Wide
97 degrees AOV
Wide Angle
75 degrees AOV
Normal
46 degrees AOV
Short Tele
27 degrees AOV
Moderate Tele
12 degrees AOV
Digital SLR
(1.6X factor)
12mm 18mm 32mm 56mm 128mm
35mm Film
19mm 28mm 50mm 90mm 200mm
6x6cm Film
40mm
(88 deg.)
50mm 80mm 150mm
(30 deg.)
350mm
(13 deg.)
The surface of a CCD or CMOS sensor in a camera is shinier than film emulsion, so there can be more light
rays reflecting off the sensor, back thru the lens. Digital-only lenses have more extensive coatings on the back
sides of the lens elements to absorb this stray light and preserve image contrast.
CANON
In the late-1980s, Canon introduced the EOS 35mm camera system with autofocus and the latest electronic
technology. Canon lenses for EOS cameras are marked EF on the front, such as “EF 28-85mm”. With the intro-
duction of digital SLRs, Canon continues with the EF lens system. All EF-series lenses for 35mm cameras can
be used on all Canon small sensor and full-size sensor digital SLRs. When Canon created the Digital Rebel,
they introduced a line of digital-only lenses are called EF-S series lenses. These lenses have the same physical
mount and electronic coupling system, but cannot be used on older Canon digital cameras and on no Canon
35mm cameras. This is because the rear portion of EF-S lenses extends deeper into the mirror chamber and
damage to the mirror on older cameras can occur. Canon EF-S lenses should only be used on the Canon EOS
20D, 30D and Digital Rebel series and newer models designed to be compatible with EF-S lenses.
Before the EOS system was introduced, Canon cameras used a different lens mounting system called the “FD”
mount. These manual-focus lenses had a mechanical aperture ring and cannot be used on EOS film or digital
cameras.
MINOLTA MAXXUM/SONY ALPHA
Minolta introduced the first 35mm autofocus camera system in 1985, sold in the U.S. as Maxxum cameras. After
merging with Konica, the Maxxum 7D and 5D digital cameras continued with the Maxxum lens system. In early
2006, Konica Minolta left the camera industry. Sony took over the Maxxum digital SLR system and renamed it
the Alpha system. The first Sony Alpha, the A100 is similar in many ways to the last Maxxum, the 5D. Lenses
interchange completely between Maxxum and Alpha cameras, so a 20-year old Maxxum lens can be used on a
Sony Alpha camera, and vice versa.
Prior to the Maxxum camera line, Minolta made manual-focus cameras that used a different lens mounting style,
usually going by the designation MC or MD. Besides a different lens mount, these lenses has a mechanical
aperture ring. They are not compatible with Maxxum or Sony Alpha cameras.
NIKON
Nikon continues with their venerable F lens mounting style used from the very first Nikon 35mm SLR camera
back in the 1950s. Nikon currently makes three series of lenses, and all will work on digital SLRs. The DX digi-
tal-only series is designed to cover the sensor on all current Nikon D-SLR cameras, but not the 35mm film for-
mat. Nikon D-series lenses are for both film and digital cameras and have a mechanical aperture ring plus elec-
tronic aperture control for full compatibility with older film cameras. Nikon G-series lenses cover 35mm and digi-
tal sensor formats, but don’t have the mechanical aperture control so the camera needs to have electronic aper-
ture capability to use this lens type.
Although the basic physical mount used by Nikon SLR cameras has not changed, there have been numerous
changes to meter coupling and autofocus operation so functionality of an old lens on a new Nikon D-SLR cam-
era varies widely. Nikon camera manuals specify the capabilities when various generations of lenses are used
on a new camera.
PENTAX
The current line of Pentax digital camera lenses is called the DA series. These lenses have the same mounting
style as the Pentax K-mount lenses for 35mm cameras, but have a reduced area of coverage since Pentax D-
SLR imaging sensors are smaller than 35mm film. As a result, if a DA lens is used on a Pentax 35mm camera,
there will be significant vignetting. DA lenses don’t have a mechanical aperture ring, so meter coupling may be
quite limited depending on the film camera’s aperture control requirements.
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