Canon Camera Zoom Lenses
Canon offers camera zoom lenses for a variety of picture-taking. Learn more about these Canon camera zoom lenses through the following questions and answers to make an informed decision about your Canon camera with zoom capabilities.What parts do zoom lenses have?
There are many different parts of a camera lens. These parts include:
- Opticals: They focus light on the image. If you hold the lens so that the front is facing up, then you are looking at the outer optical. There are probably several more behind the one that you can touch.
- Filter threads: At the front, you will see threads allowing for the attachment of different filters to change the composition. Choices range from ultraviolet, polarizing, and neutral density to special effects and color filters.
- Focal length ring: This ring turns either manually or with a small motor, allowing the unit to zoom in or out on a subject.
- Aperture: Allows the photographer to determine how much of a scene should be in focus.
- Lens mount: On the bottom of the lens, you will find a metal part called the lens mount, which connects the lenses to the body of the camera.
If you examine a Canon zoom lens, you will see a variety of numbers. The focal length is a list of numbers followed by the letters "mm." This is the measurement of the distance between the sensor, at the back of the lens and the front glass. On a 70-200mm lens, for example, 70mm is the widest and 200mm is the farthest it will go. You will also see a ratio number that represents the aperture number. Camera lenses with low aperture numbers let in more light. This enables the photographer to capture photos without a flash in low-light conditions. The phi number represents the size of the filters that you can use.What are the types of zoom lens mounts used?
When Canon introduced their first SLR, they made R-mount lenses featuring a breech-lock with two pins at the rear. Since that time, the company has made many lens-mount systems including:
- FD: These optical glasses feature a breech-lock mount, which communicates between the camera and the unit.
- FL: Introduced by the company in 1964, these lenses were the first with autofocus built into them and the first with full-aperture metering.
- EF: The EF lenses with their bayonet mounts feature a dedicated electric motor.
- EOS: The electro-optical system is able to autofocus based on where the user is looking in the viewfinder.
- EFS: These optical glasses are small and are designed to fit APS-C DSLRs.