Camera Lenses and it uses
The first hurdle one faces during purchase decision in Photography is choosing a Camera body that suffices the Budget and Utility the camera is intended to be put into. The next challenge and probably a little more difficult hurdle is deciding upon a Lens to be used with the body. Yes, most beginners find big Lenses (Zoom Lenses) very attractive but all depends on your genre of Photography you wish to pursue. Basic understanding of Camera Lenses helps you to have more control over your creativity. Deciding on a perfect Lens is conjunction of Budget, Size, Weight, Lens Speed and Image quality.
How does a Lens work?
A Lens contains one or more Lens Elements. Lens Elements are pieces of shaped glass with an objective to bend light. Each element has a different function but the sole objective is to act in unison to produce a sharp image on the Sensor / Film.
Although, it may sound simple but a huge amount to Technology goes into designing Lenses. The biggest challenge is to you don’t want the Lens to be sharp at just one place instead you the Photograph to be perfectly sharp across the width of the Photograph.
What is Focal Length?
Focal Length is the distance in millimeters from the optical center of the Lens to the Imaging Sensor when the Lens is focused at Infinity. Sounds too geeky, no worries – in simple terms it is easier to think the Focal Length affects Image size. The following Image will help in further understanding.
For a camera with a Full Frame Sensor, a standard lens that gives a similar perspective of the Human eye is 50 mm. Lenses which has Focal lengths less than 50 mm are referred as Wide Angle, whereas for Lenses where the Focal Lengths is larger than 50 mm is referred to as Telephoto Lens.
A Wide Angle Lens have a Shorter Focal Length and hence will have a larger spectrum of the area being photographed. Whereas, a Telephoto Lens have a Longer Focal Length and will have a shorter spectrum of the area being photographed.
What are Zoom and Prime Lenses?
A Prime Lens is a Lens with a Fixed Focal Length. These Lenses are also referred to as “Fixed Lenses” or “Block Lenses”. The Lens has a set angle of view which cannot be changed unless you physically move in or out. To zoom in you need to move towards the object and to zoom out the vice versa. Prime Lenses have a specific focal length, e.g. Nikon 50 mm f/1.8G and Canon 800 mm f/5.6.
A Zoom Lens on the other hand has variable Focal length. By turning the Zoom ring, you move the optical Elements (Refer Photograph 1) inside the Lens to achieve a different angle of view. Here, you can Zoom in or Zoom out without physically moving as you need to do in case of a Prime Lens.
Prime Lens Advantages:
- Cost – Prime Lens are relatively cheaper as compared to their Zoom counterparts.
- Size & Weight – The Size and Weight of Prime Lenses are comparatively lower since moving parts are barely present.
- Learning Curve – Since Prime Lenses are the oldest for of Lenses, you have to physically move in or out by walking. It therefore allows the Photographer to use the lens to it’s full potential.
- Aesthetics – Zoom lenses can have a maximum aperture of f/2.8, were as Professional Prime Lenses can go as wide as f/1.2 rendering beautiful blurred background called “Bokeh”.
- Low Light Performance – As Prime Lenses can easily open upto f/2 or even upto f/1.2, the Lenses can perform wonderfully in low light situations.
Zoom Lens Advantages:
- Versatility – The primary reason for choosing a Zoom lens is versatility. It allows the Photographer to handle a variety of situations. He can shift from a Wide Angle to a Tele Photo just with the turn of the Zoom ring.
- Image Stabilization – Modern Zoom Lenses offers 3-4 stop image stabilization. Whether it Canon’s Image Stabilization (IS), Nikon’s Vibration Reduction (VR), Sigma’s Optical Stabilization (OS) or Tamron’s Vibration Compensation (VC) all allow you to shoot sharper Photographs at slower shutter speeds.
- Portability – Although they are comparatively bigger and bulkier than Prime Lenses, still a single Zoom Lens can replace two or more Prime Lenses, indirectly helps in reducing weight.
Other types of Lenses and their uses?
Camera Lenses come in either fixed (prime) focal lengths, or zooms, which cover a range of focal lengths, which we have already discussed above. The different Focal Lengths are grouped into categories for different types of lenses.
1. Wide Angle Lenses: Traditionally, a super wide-angle lens is classified as anything under 20mm. Wide-angle is 21-35mm. Wide-angle lenses are most commonly used for photographing landscapes and architecture, although they are often also used for photographing large groups of people.
2. Prime Lenses: A standard lens has a focal length range of 35-70 mm. The most common standard lens is a fixed 50 mm lens. Standard lenses are most commonly used for documentary and street photography. The Canon 50mm f/1.8 lens is an example of a standard, fixed lens.
3. Medium Telephoto / Portrait Lens: The focal range between 80-135 mm is nearly always used by portrait photographers. These are specialist lenses, but can be surprisingly reasonably priced. The Canon EF 100mm f/2.8 Macro USM lens is an example of a one of these types of lenses.
4. Telephoto: Any lens with a focal length of between 135mm and 300mm is a True telephoto lens. Telephoto lenses are traditionally used for sports and wildlife photography, but their essential function is to bring distant objects closer.
5. Specialist Lenses: There are a variety of specialist lenses available. Some of the more common are:
a. Super Telephoto: These have a focal length of more than 300mm, and are used by dedicated sports and wildlife photographers.
b. Macro: These lenses are able to focus closer to an object than normal lenses, offering a 1:1 ratio. They are used for still-life photography of small objects.
c. Fisheye: These are on the edge of wide-angle lenses, and give a distorted view of the subject matter. The center of the image is magnified, and objects diminish in size in all directions around it.