Lenses are tubes with elements (usually glass) that direct light onto your camera sensor.
Lenses come in a variety of focal lengths. The focal length is an indication of how wide or narrow the field of view in your photo will be. The shorter the focal length, the wider the angle. Conversely, the longer the focal length, the more "zoomed-in" the photo will appear.
Focal lengths and field-of-view are also affected by sensor size, but that'll be the subject of a future discussion.
For simplicity, this post will assume that all discussions relating to focal lengths are based on their use with full frame cameras, which means digital cameras with full-frame sensors, as well as 35mm film cameras.
The "standard" lens
Shot at 50mm
50mm lenses are also known as “standard” lenses because they are said to look the most similar to how we perceive the world around us through our own eyes. A 50mm lens can also offer a good balance between size, quality, price, and versatility.
Some alternative focal lengths that can still be considered within the "standard" lens range are 40mm (which some people say looks even more similar to how our eyes perceive the world) and 55mm.
Wide-angle lenses
Shot at 17mm
Wide-angle lenses are commonly regarded as lenses with a focal length of 35mm or less. Ultra wide-angle lenses are commonly regarded as lenses with a focal length of 21mm or less. Some examples of common wide-angle focal lengths include:
35mm
28mm
24mm
21mm
18mm
16mm
Telephoto lenses
Shot at 300mm
Strictly speaking, a telephoto lens is any lens in which the physical length of the lens is shorter than its focal length. However, it can colloquially be used to refer to lenses with a focal range of 75mm or more. Some examples of common telephoto focal lengths include:
75mm
85mm
90mm
100mm
120mm
200mm
300mm
Primes vs Zooms
You may have noticed that I've been talking about lenses with fixed focal lengths. These are called "prime" lenses.
"But what about zoom lenses" you ask!
Zoom lenses let you "zoom" in and out, offering you the advantage of working with a range of focal lengths. However, prime lenses usually offer larger aperture sizes. Larger apertures have better light-gathering capability, allowing you to shoot in poorer light, and have a narrower depth of field, which results in more blurring of the background (called "bokeh").
You can see examples of bokeh in the portraits above, taken at 50mm and 300mm. I'll discuss bokeh in more detail in a future post.
For learning how to get the most out of your lenses, I'd recommend getting a cheap prime lens. A basic 50mm f1.8 prime lens is often one of the cheapest lenses you can buy new, and costs even less second-hand. It's a good practice tool, will still give you good results as you improve, and if you decide to upgrade later on, it's cheap enough that you can keep it as a spare/backup (or you could also sell it).
The photo above was shot with a manual focus 50mm 1.8 Nikon Series E lens. It can be found on eBay for S$30 - $50. That's around US $25 - $35.
Generally I'd recommend getting an autofocus lens, and an entry-level 50mm 1.8 should come in (new) at below US $150 for a major brand like Canon or Nikon, and below US $100 for a third-party brand like Yongnuo. But the point of this photo is that cheap lenses can produce nice photos.
Please consider sharing your photos with the community by tagging #dharmaportraits on your Instagram photos - I'd love to see how you're using these tips to create beautiful photos.