Lenses for indie filmmaking

Choosing a lens (or multiple lenses) to use on your independent film or video project is essential to nailing the "look" of your project.

I'm not a professional DP (Director of Photography) and I don't come out of the camera department, so I'm fairly ignorant (and in awe) of lens technical specs. But as a director, I'm drawn to the narrow focus and zoomability of a long lens (turns out, size does matter -- with a lens). The long ones just look so much more cinematic than a stout wide lens to me.

But really, I don't know what the hell I'm talking about when it comes to lenses. All I know is that it's "all about the glass" -- lenses make a huge difference in the visual look of the film.

In fact, lenses are far more important than the camera itself. All things being equal, most HD cameras perform well enough for the most likely viewing experiences for our projects: Internet video and DVD, plus any 1080 or 720 HD exhibition. On the other hand, the lens will make a huge difference; it's the difference between looking cinematic and like community TV.

So when I came across a basic primer on lenses by Matthew Galvin of Active Matrix Networks on the SF Indieclub Yahoo group, I learned some basics and wanted to share it.

Read on to learn the fundamentals of lenses for filmmaking.

Like many equipment selections and specifications, your choice of lenses greatly depends on what brand you follow, what your experience is, and what you choose to utilize as the appropriate tool for an individual scene or sequence. There is no single "best" choice for any situation.

"Professional" lenses generally have 3 important selection factors.

• The mount of the lens. This indicates what hardware allows the lens to fit with other lens elements, or with the camera body type. These are specified by camera manufacturer on SLRs, DSLRs, etc. (Canon, Nikon, Sony, etc) and by mount type designator on film and 35mm emulated cameras (Red, Arri Alexa, SI, etc.). Usually camera packages specify PL mount, bayonet mount, etc.
• The speed of the lens. This indicates how much light the camera can acquire an image at, and is specified in f/stops or t/stops.
• The "quality" of the lens. This indicates areas or levels of distortion. Lenses are made of glass and/or plastic. They ALL distort light to some degree. Some lenses distort more than others, and some have noticeable areas of significant distortion. Obviously "quality" is somewhat subjective, but distortion parameters and aberrations can be physically measured.

Also, how solid is the lens and how repeat-ably can it be focused or zoomed accurately? Can it be focused using a whip or follow focus unit? How accurate is the focus and the focal/zoom markings. Is there noticable "play" or "wiggle" in the lens mechanism?

So, you will see a whole bunch of descriptive numbers for a particular lens:

• Angle of view is expressed in millimeters (in zoom lenses, this is expressed as a range, in fixed or prime lenses as a single measurement)
• Mount type is expressed via the fitting type (PL, C, Bolex, Canon, etc.)
• Lens speed (usually expressed in maximum aperture f or t stop)
• Fitting or cap diameter (useful for filters, matte boxes, etc.)
• Number of elements (less important except where this causes significant distortion)
• Occasionally, you will also see descriptions of the distortion parameters of a particular lens. This is usually for higher-end lenses and is expressed as a series of graphs.

I would heartily recommend renting or borrowing a variety of lenses, as well as reading cinematography blogs and blurbs and talking with a lot of cinematographers to find the best lenses for your particular project or projects.

There are tons of options for rent, beg, borrow . . . I own Canon and Minolta mount in a variety of flavors and provide rental and lending options.

Type in "lens rental" in a search engine to turn up more options.

Thanks again to Matthew Galvin of Active Matrix Networks for allowing us to publish this great brief -- but thorough -- overview of lenses.

If you want to really dive deeper into glass, Matthew suggests you offer yourself as an AC (Assistant Cameraperson), to work with a DP and see how they choose what to use. Nothing beats experience.

Comments

[mark]

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[Alejandro]

Actually, angle of view is not expressed in millimeters, but in degrees. What's expressed in millimeters is focal length, which determines field of view FOR ONE PARTICULAR FILM/SENSOR SIZE. For example, a 50mm is considered a "normal" lens on 35mm stills, VistaVision cameras and "full-frame" cameras like the Canon 5D, because 50mm is close to the length of the film/sensor's diagonal. It's close to the angle of view of a single human eye. On the other hand, the same 50mm lens on an APS-C or Super35 camera (like the Canon 7D, 60D, T3i, etc.) will behave as a short telephoto lens, because of the smaller sensor acting as a "crop factor". In fact, it'll have the same angle of view as an 80mm lens would on a full-frame/VistaVision/35mm still camera.

It's not too hard to learn this. Just grab a DSLR and experiment a bit. I generally find it easier to develop these kinds of technical skills with stills rather than video.

[Bad Vegan]

Thanks for the info Alejandro. I wish I was more of a gear nerd and/or had come out of the camera department. All I know is that the longer the lens, the more "cinematic" and arty it looks to my eye due to the narrow depth of field. But it's great to get that clarity about the relationship of lens to film/sensor size.