Reading the Names of Camera Lenses

Reading the names of SLR lenses may look like a daunting task to a newcomer, but with a little knowledge of basic photography and the names of a brand's lens designations (and their abbreviations), it's actually pretty easy. The different parts of the name of a popular Nikon lens are broken down in Fig. 1 below.

Parts of a lens name

Fig. 1: Parts of a lens name: brand, focal length(s), maximum aperture(s), other

Here are more detailed descriptions of each part:

  • Brand: the maker of the lens such as Nikon or Canon. This part may also contain information on the type of camera that the lens is compatible with, for example Canon EF-S indicates a lens that only works with cameras that have APS-C sized sensors.
  • Focal length(s): the distance between the centre of the lens and the camera's focal point (the sensor on a digital SLR) when an in-focus image is formed of a distant object. With a zoom lens, this number will be a range like 18-200mm, which means that the lens can use focal lengths anywhere from 18mm to 200mm as needed to pull away or zoom in on a subject. A prime lens only has a fixed focal length and will look something like 10.5mm.
  • Maximum aperture(s): describes the widest diameter to which the camera's aperture (a hole that lets in light) can adjust itself. On a zoom lens, like the lens focal lengths, this number will also be a range like f/3.5-5.6. The starting number is the maximum aperture at the camera's shortest focal length, and the ending number is the maximum aperture at the camera's longest focal length.
  • Other: this is a list of various features and/or integrate technologies of the lens. These abbreviations vary from manufacturer to manufacturer, so you'll have to look up the ones that you don't recognize.

The list below describes each lens feature from the example in Fig. 1:

  • G: indicates a gelded lens. These are lenses that are not equipped with aperture rings in order to save cost. Instead, the aperture size is changed by the camera it's mounted on. As Ken Rockwell puts it: G is not a feature, it is a handicap.
  • ED-IF: actually a combination of two features, ED indicating extra-low dispersion and IF indicating internal focusing. ED is a glass technology that allows for a fast super telephoto without the chromatic aberration that would normally occur and reduce its images' sharpness. IF was an advancement that allowed lenses to do all their focusing internally, where previously the entire lens had to move in and out to focus (more on internal focusing).
  • AF-S: indicates autofocus via silent wave motor. Lenses with this feature allow a lens to be focused manually at any time, even if autofocus is still turned on.
  • VR: indicates vibration reduction, Nikon's technology to compensate for the natural shakiness of your hands while a photo is being taken. Canon's similar technology is called IS (Image Stabilizer) and Sigma's OS (Optical Stabilizer).
  • DX: indicates compatibility with Nikon's line of small-frame cameras. The sensor in DX series cameras shoots a smaller 16 x 24mm frame while the FX series shoots at full-frame size.

Posted on March 17, 2009 from Calgary

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