Full frame sized imageLenses that create APS-C sized image are designed for digital only. They cannot be used on cameras that have image sensor larger than the APS-C format. These lenses are not suitable for film cameras either. Ultrasonic AFLenses with ultrasonic focusing mechanism tend to be quiter and faster than traditionally focusing lenses. No stepping motor AFLenses with stepping motor focusing mechanism are better for contrast based focusing, and are quiter and faster than traditionally focusing lenses. No Low Dispersion lens element is usedLow Dispersion lens elements help to reduce chromatic aberration. Built-in image stabilizerImage stabilization helps to reduce blur caused by hand shake, especially at high focal length or in low light situations. Image stabilization can give 1 to 3 stop advantage over none stabilized lens, based on the reciprocal rule. Metal mountCheaper lenses are usually equipped with plastic mount, while more expensive, professional lenses have metal mount. In general, metal mounts are more durable, and a good thing to have when lenses are changed a lot. When a camera is used mainly with one lens, the material of the lens mount is not that important. Internal FocusingInternally focusing lenses don't change their size while setting focus. The front lens is fixedThe fixed front lens is not rotating during zoom and/or focusing. This allows the photographer to use petal shaped lens hood. Fixed front lenses also make the use of polarization filters a lot easier. Weather SealedWeather sealed lenses are protected from dust and water. While they are not water proof, these lenses can be used in rain and other humid environments. Some sealings only provide protection against dust or water, not both. Sealing is only available when the lens is used on a similarly weather sealed camera body. Supports drop-in filtersDrop-in filters are used in those lenses where either the front lens is too large, or the field of view doesn't permit the use of traditional filters at the front of the lens. Usually bright tele and ultra-wide angle lenses support this filter type. |
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The EF 400mm f/4 DO IS USM is the worlds first super telephoto lens incorporating "Multi-Layer Diffractive Optical (DO) Element", for camera lenses, and is considered a major breakthrough. The outstanding feature, being its superb ability to correct chromatic aberrations. By incorporating this optical element in the optical design the EF 400mm f/4 IS USM is much smaller and lighter than a comparable lens having conventional optical elements. The Multi-Layer Diffractive Optical Element developed by Canon is a milestone optical element possessing the characteristics of both fluorite and aspherical elements, which has led to the production of high-performance camera lenses.
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Available mount(s) | Canon EF |
Application(s) | Sports, Wildlife |
Category(s) | Super telephoto |
Multiplier | 1× |
Stabilizer | yes (2 f-stop advantage) |
Focal length | 400 mm (prime) |
Lens construction | 17 elements in 13 groups |
Angle of view |
35mm: 6.17° digital: N/A |
Number of blades | 8 |
Maximum aperture | f/4 |
Minimum aperture | f/32 |
Minimum focusing distance | 350 cm |
Magnification | 0.12× |
Filter size | 52 mm |
Size | ∅ 128 × 232.7 mm |
Weight | 1940 g |
Notes |
Mechanical full-time manual focusing built-in. Filter: drop-in |
AF speed | N/A |
AF sound | |
Internal focusing | yes |
Internal zoom | N/A |
Fix front lens | yes |
Mount type | metal |
Weather sealed | yes |
Drop in filter | yes |
Ultrasonic AF | yes |
Stepping motor AF | no |
APS-C sized circle | no |
Low dispersion lens element | no |
Hard case | included |
Soft case | N/A |
Lens hood | ET-120 |
Tripod adapter | N/A |