Understanding Camera Lenses

Photography’s expressiveness is due to the creative use of the lenses. They shape how you see the world through your viewfinder.

Camera lenses have an inherent distortion quality. You need to accept that fact to capture your vision on film or in the image sensor.

The Focal Length

Standard Lens

The focal length is a primary characteristic of a lens.

The focal length of a lens is the distance between its optical center and the camera’s image sensor (or film plan) when it is focused at infinity.

We need to understand the definition of focal length. The point at which two sources of light enter a lens is called the “optical center”.

A shorter focal length lens provides a wider field but less magnification. Longer focal length lenses, on the other hand, provide a wider field of vision but offer greater magnification.

The focal length of an interchangeable lens on DSLRs is measured in millimeters.

The lens barrel usually displays the focal length and the size of the adaptor rings.

The Lens Ratio

The Lens Ratio

If you look at the front of your lens barrel you will see a number (1:2.8-4 to 1:3.5-5.6, etc), which indicates the maximum aperture.

The aperture controls how much light the lens transmits onto the sensor.

The quality of the lens will be determined by its maximum aperture value. A high quality zoom lens will have a constant fstop across the focal range (i.e. A f/2.8 at 35mm is the same as a f/2.8 @ 80mm; whereas a lower quality zoom lens’ f-stop changes as you move up the focal range (i.e. A f/3.5 at 28mm and a f/5.6 @ 80mm; you lose at least one stop of light when you zoom up the focal length, from wide angle to telescope.

A lens with a lower f-number (large maximum aperture) is better quality and allows you more freedom to use it.

This lens, for example, is “brighter” and allows you to take photos even in low light conditions.

These bright lenses can also be used to create a shallow depth of field.

Note that professional lenses are f/2.8 and lower. Professional lenses will be more expensive.

Standard/Normal Lens

Standard Lens

Standard lenses have a fixed focal length (50mm 85mm 100mm) and reproduce very accurately what the human eye sees in terms of perspective, angle and view.

The standard 50mm lens can be used with a 35mm film camera, or a full frame DSLR.

You can use a higher focal length (85mm or 100mm), which makes them ideal for portraiture. They combine a wide aperture with softening any background detail to make it less distracting from the main subject.

Wide Angle Lens

Wide Angle Lens

Wide-angle lenses have a shorter focal length (between 10 and 42mm) than standard lenses.

This allows you to capture a wider angle of view. Wide-angle lenses are a great choice for outdoor landscapes and group portraits.

Wide angle photography can capture the entire scene without missing any key elements.

Wide-angle lenses can be used to capture deep DOF.

Telephoto Lens

Telephoto Lens

Telephoto lenses (100mm-800mm) are available that provide a narrow field view.

The long lenses allow you to compress distances (and also reduce depth perception) and pinpoint objects far away.

They possess a high degree of resolution and a shallow DOF. Even the smallest lateral moment can remove a subject from view.

Telephoto lenses can be used for portrait, sports, documentary, and wildlife photography.

These cameras allow you to capture subjects up to hundreds of feet away.

Zoom Lens

Zoom Lens

Zoom lenses are very useful because they have adjustable focal lengths.

You can choose between a wide-angle or telephoto lens (e.g. You have a lot of options for composition.

Zoom lenses have an aperture, which is the tradeoff. These lenses are limited in their ability to open and let in light due to the large number of elements that go into making them.

You will have to give up speed unless you are willing to spend a lot of cash.

Fisheye Lens

Fisheye Lens

Fisheye lenses are specialized wide-angle lenses that provide extremely wide images. They transform straight lines into curves.

Sometimes, it can produce convex, circular, or oval images. It does this by distorting perspective and creating a 180deg picture.

A fish-eye lens has a focal length range between 7 and 16mm.

Macro Lens

Macro Lens

Macro lenses can be used to take close-up, or “macro”, photos.

These lenses have focal lengths ranging from 50 to 200mm. These lenses can focus sharply at macro distances, but they lose their sharpness at longer distances.

These lenses allow the photographer to capture larger or life-size images of subjects such as wasps, butterflies, flowers, etc.

Tilt-Shift Lens

Tilt-Shift Lens

Tilt-Shift lenses allow you to alter the vanishing points. This is useful when shooting buildings. It allows you to change the perspective of an image so that parallel lines don’t converge.

You can also use the tilt-shift lens to focus on specific areas of an image.

Image-Stabilization Lens

These lenses have small gyro stabilizer sensors and servo-actuated elements that are supposed to correct camera shake in longer focal length lenses or low-light situations when shutter speeds must be slower to achieve an effective EEV.

These lenses are claimed to allow the user to take handheld photos at 2 to 4 stops slower shutter speeds (exposure 4-16 times longer than required to produce sharp images).

Conclusion

There are many lens options, each offering a unique image.

The creative part of a photographer’s creativity is choosing the right lens to capture her or his vision of the world.