Camera Lenses 101

Camera lenses are easier to understand than they seem.

When you're looking for a new camera, you're often bombarded by technical terms, and it can be easy to feel out of your depth. Camera lens related terminology is not nearly as intimidating as it seems.

Focal Length

This is the measurement displayed on cameras in millimeters, the most common being 35mm. A lower number means a wider angle of view. Anything between 35 and 70mm is normal. A larger number means the lens is a telephoto lens, which has a narrower angle of view. A wide lens is used for landscapes, and a telephoto lens is ideal for taking portraits.

Lens Aperture

Camera lenses also have an "F" number. This relates to the maximum aperture of the lens. The aperture is the amount a lens can open or close to vary the amount of light that it lets in. A lower "F" number means more light can get in, and as a result, it takes less time to capture the image. With a higher "F" number, less light can come in, which means it takes longer to snap a photo.

Depth of Field

The depth of field is the portion of your photo that is in crisp focus. Anything outside of that section loses focus. A high "F" number leads to a wider depth of field, and a low one gives a narrow depth of field.

References

• Cambridge in Colour: "Understanding Camera Lenses"
• Cambridge in Colour: "Understanding Depth of Field in Photography"