The Wonderful World of Lenses
So you want some lenses. You don’t? Wrong, yes you do. Like with the post on sound, forget your camera. Lenses are arguably the most important pieces of equipment in your arsenal and can, quite literally, last a lifetime. “Buy once, cry once” heavily applies here. There are so many options out there and so many numbers/letters to learn, so before diving in to the wonderful world of lenses, here are some basic terms.
“Focal length” is the “mm” on your lens. 40-60mm is generally a “normal” look, 75mm+ is considered a “long” focal length (lenses that see far), below 40mm is generally considered a “wide” focal length (lenses that let you see a wider area around you) and may or may not be “fish-eyed” (distorted on the sides, creating sharp angles on the ends).
“Fast” or “Slow” refers to how open your lens can be – how low can the aperture go (letting in more light, giving a shallower depth of field)? Fast zooms are generally f/2.8 and lower, fast primes f/1.8. It’s important to note that there is no number-definition for “fast” and “slow,” it’s more of a guideline. Fast lenses are generally more expensive than their “slower” counterparts.
So with these terms in mind, let’s get to some things you need to consider when buying a lens.
Prime vs. Zoom: A prime lens is a lens that does not zoom. A zoom lens has an “adjustable focal length,” meaning you can zoom in and out. The advantage with good prime lenses is that they are generally more “precise” than zoom lenses as they do not have the multiple pieces of glass that a zoom needs. Primes are also usually more “accurate” and provide a nice cinematic softness while still being sharp, This does not mean zoom lenses are imprecise, though cheap ones often are (as are cheap primes). Primes are also generally faster than zoom lenses, with most zooms tapping out at f/2.8 and even the cheapest of prime lenses being able to go lower. This makes them better equipped for lowlight situations.
Used or New: Lenses are wonderful because if they are well-built (which many are) and the owner takes good care of them (you do, right?) then they can last a very long time and be great used purchases. Many sites have a strict system for rating a lens. The biggest consideration you should have when buying a used lens is the condition of the actual glass. Does it have scratches? Cracks at all? Any fungus (this happens with old glass)? After that, make sure the focus rings and aperture rings are listed as fully functional, otherwise you’ll have poor or no control over the lens. Anyone worth their salt selling lenses will list EXACTLY the condition it is in and will provide several photos. Return policies are always a huge plus. KEH.com is an extremely popular site with some of the best product grading I’ve seen thus far, and Lens Authority (Borrow Lenses’s retail arm) is also a great site for finding used but well-maintained gear.
What Now? You must ask yourself 3 questions: Do I need a zoom or prime for most of my work? Do I need it to be a fast lens? What focal lengths will I be working at? Documentary/Broadcast shooters often need fast, precise zooms. If you’re “making a movie” (non-documentary) you generally need sturdy, fast prime lenses. That being said, you should never restrict yourself to just primes or just zooms – virtually no one does for all their work.
This is just a primer. There are so many considerations to take into account when one is buying a new lens, but we hope this helps you get started. Now go invest in some glass!
This post is an adaptation/updated version of a previous post done by co-founder Greg Tilton Jr. for 52 Businesses back in April of 2014.