What Lens to Get? Part Two: FOV and Focal Lengths

By Sareesh Sudhakaran

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In Part One we looked at how to define a subject, a shot and a space.

In this part we’ll put all this information together to find what lens to get if you’re a beginner without experience.

Area

Your area of operation varies widely, so as a beginner you are not expected to know it. Heck, even pros walk in blind sometimes, so don’t worry about it.

How can we know how close or far we can get, without the experience to back us up? Simple, we look at locations. Here are a few common locations:

• Home – Living Room
• Home – Bedroom
• Senior Executive’s Office
• Employee’s Cubicle
• Place of Worship
• Streets
• Large Hall
• Studio
• Park or Garden
• Open Space (where you can see the horizon), Aerial or Underwater
• Tight Corners (dictated by the specific geometry of rooms or spaces)
• Sports Arenas
• Vehicles

You’d be surprised how most image-making is confined to these generalized locations. These ‘locations’ are just ‘boxes’, when you come to think about it. No matter what location you might be faced with, it is simpler to think of them as ‘boxes’ of space.

We broke down our human subject into boxes of shots. We can do the same with spaces. Let’s start with some examples:

• Typical large living room – 16 x 16 feet
• Typical small living room – 12 x 12 feet
• Typical large bedroom – 12 x 12 feet
• Typical small bedroom – 10 x 10 feet
• Large Office – 12 x 12 feet
• Conference Room – 10 x 25 feet
• Small Office or Cubicle – 6 x 6 feet
• Basketball Court or hall – 94 x 50 feet
• Football/Soccer Field – 200 x 350 feet
• Car – Less than 4 x 4 feet
• Typical mid-size sound stage – 100 x 150 feet
• Small sound stage – 50 x 50 feet

Even sound stages fall below the 300 feet mark, so we were quite justified in setting our upper limit at 300 feet.

As far as the lower limit is concerned, most shooting happens at no closer than 4 feet. There’s nothing stopping you from filming a human at 2 feet, but try it, even for fun. I’ve generally found anything closer than 4 feet is supremely uncomfortable to the talent. Typically, 6-10 feet is the sweet spot. But just for fun’s sake, we’ll fix the minimum distance at 3 feet.

Small spaces will limit you. Typically, you’re always shooting within a distance of 25 feet. If your location is a large hall, you might be able to shoot at 100 feet or more. If you’re shooting soccer, you might be able to catch action at the other end of the pitch with a super telephoto lens.

You can go even further, because there are lenses that let you shoot sport in larger arenas, or wildlife, etc. But these are specialized activities. As a beginner, if you already know you’re going to do this, your choices are somewhat limited (not to mention expensive).

Let’s not make it more complicated. The closest distance is 3 feet and the farthest is 300 feet.

Now, let’s find the vertical angle of view (values in degrees):

Assumption: Extreme long shot has a vertical length of 15 feet.

Don’t let the table scare you. You don’t need to do any math. I’ve done it for you.

It’s basic trigonometry. Knowing the height of our frame (part of our subject we want to fill the frame with) and the distance to the subject, we can calculate the angle of view required.

For the sake of simplicity, let’s assume we are shooting on a full frame sensor camera (36mm x 24mm). We can always convert to any other length later using the crop factor.

The following table is from Wikipedia, and it shows typical angles of view for each focal length:

We are mainly concerned with the vertical angles. We can simply replace the angles with the focal lengths in our own table, to get this (values in mm):

Important: Fields of View are not necessarily the same for a given focal length from two different manufacturers (or even versions of the same lens). However, the differences are negligible for our purposes.

Wow. Here are some observations (all based on full frame sensors):

• When you’re less than 30 feet away from the subject, you don’t need a focal length greater than 300mm (full frame equivalent).
• If you’re shooting at greater than 100 feet, then you start at 200mm.
• Between 30 feet and 100 feet you start at 70mm.
• Focal lengths less than 10 mm are extremely wide, and you are unlikely to find one that is rectilinear (not fish-eye) and still at f/2.8.
• Focal lengths from 8 to 14mm are only necessary if you’re shooting large buildings or landscape at close distances.
• At 6 to 30 feet, 20mm to 200mm is fine.

What does this all mean? Here is my analysis:

• Is it a wonder that the most-used zoom lens for a full frame camera is the 24-70mm? Most people shooting weddings, beauty, drama, etc. stay in this range.
• For occasions when you’ll need to go further than 30 feet, you could use a lens that starts at 70mm and ends somewhere in the 300mm mark. Is it a wonder then, that most manufacturers have a telephone zoom in the 70-300mm zone?
• Finally, for those who need wide angle, the usual range is 17-35mm or so.
• The most useful regular lens is 35mm. Is it a wonder that most still frame cameras with a fixed prime chooses 35mm (FF equivalent) as their focal length of choice?
• The most useful long lens is 75/85mm. This is the most widely used focal length for portraits.
• The most useful mid telephoto focal length is 135mm.
• The most useful telephoto focal length is 300mm.

So, theoretically speaking, if a manufacturer offered us an 18-300mm lens, we’ll be gold. Guess what? They do offer this, with a catch: there isn’t one with an f/2.8 aperture across this entire zoom range.

Which brings us to factors other than focal length.

Factors to consider before choosing lenses

Here are a few important considerations:

• I explained in the chapter on Lenses in the Comprehensive Guide that you must get a lens with an f-number of at least f/2.8. Now would be a good time to read the entire chapter.
• It is better to get zoom lenses and not prime lenses if you’re a beginner, simply because you don’t know your favorite focal lengths yet. Nor do you have experience with tight spots and curve-ball situations. Get a zoom lens, period.
• The lens must have a usable and rugged focus ring, so you can use a follow focus system, or your hands.
• Image Stabilization isn’t mandatory, but useful sometimes. If you can afford the Image Stabilized version of a lens, go for it. You can always turn it off if you don’t want it.
• Weather sealing is a big plus, but a luxury for most beginners. Don’t sweat it.

What Lens to Get?

Okay! Based on everything we’ve covered, this is my advice:

• If you can only get one zoom lens, get a lens with a focal length range of 24-70mm f/2.8 (full frame sensor). If you’re shooting on an APS-C/Super 35 sensor, the equivalent focal length is 16-50, which is why they give you an 18-55mm kit lens.
• If you can afford two zoom lenses, get the 24-70 (for full frame sensors) and the 70-200 f/2.8.
• If you can afford three zoom lenses, get the entire zoom range – 16-35mm (12-24mm for Nikon), 24-70mm and 70-200mm – all at f/2.8.
• Don’t buy prime lenses until you know which focal lengths you really need. Only experience and an artistic eye can tell you this.

Now, here are some concrete recommendations for your first lens:

Full Frame Sensor (EF Mount)

• Entry-level (<30 feet) – Canon 24-105mm f/4L
• Professional-level (<30 feet) – 24-70mm f/2.8
• Entry-level (>30 feet) – 70-200mm f/4
• Professional-level (>30 feet) – 70-200mm f/2.8

APS-C Sensor (EF and EF-S Mount)

• Entry-level (<30 feet) – Tamron 17-50mm f/2.8
• Professional-level (<30 feet) – 17-55mm f/2.8 (EF-S), or the 16-35mm f/2.8 (EF)
• Entry-level (>30 feet) – 70-200mm f/4
• Professional-level (>30 feet) – 70-200mm f/2.8

Micro 4/3 Sensor (m43 Mount)

• (<30 feet) – 12-35mm f/2.8
• (>30 feet) – 35-100mm f/2.8

If you can’t afford any of these lenses (f/2.8), then go with the kit lens. It’s not as bad as people make it out to be. Sometimes, it’s even hard to tell them apart from a professional lens 10 times the price!

We’re done. Hope you have found this article useful in determining your first lens. If you want to find exact recommendations for each camera, look no further than the chapter on Lenses in the Comprehensive Guide to Rigging ANY Camera.

“What lens to buy?” You’ll hear this question many times throughout your career. Whenever you do, please remember not to give advice based on hearsay or subjective opinions. There is a reason manufacturers divide their zoom ranges into certain groups. They know better than most people.

What was your first lens? Tell me about it. Did it help or hinder your growth as a filmmaker or cinematographer?
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