Lens Packages
By Neil Blevins
Created On: Aug 1st 2014

When doing a live action film shoot, you buy or rent your camera (usually rent), and then you choose a set of lenses that you intend to shoot on. This set is usually referred to as a "Lens Package" (I've also heard it referred to as a "Lens Kit"). While you could potentially use an unlimited number of lenses, in general, you'll find a Director or Director of Photography will tend to favor a small subset of lenses, in some cases, and entire film might be shot using only 3-4 lenses.

How does this affect us in CG? Well, in CG, you can change your lens to whatever you want. This gives you great power, but it also can break consistency. Like in live action, maybe every time there's a closeup on a character, the director chooses their goto 35mm lens. In CG, every closeup might have a completely different focal length, which means your character starts to look weird because every shot their face is distorted in a slightly different way. So I highly recommend, if you're doing a CG film, to make yourself a lens package, a small set of lenses you'll be using for your virtual shoot. It will not only guarantee more consistency (like how many films color grade a sequence to have a consistent color scheme), but it will also more closely emulate the way a real live action shoot is done. So if you're trying to emulate a live action feel, best to emulate some of their techniques as well, and give your virtual camera the same constraints the live action camera has.

Lets talk about a simple lens package, which might consist of a wide angle lens (lets say 35mm), a telephoto (lets say 100mm), and a 50mm, which is approx the same as what the human eye sees. Wide Angle lenses tend to distort your subject, bulging things close to camera, and there tends to be more apparent distance between your foreground and background objects. Telephoto lenses tend to flatten out space, decreasing the apparent distance between foreground and background objects. But more on this topic in a different tutorial. From the perspective of Lens Packages, having at least these 3 types of lenses would let you achieve a number of different types of shots and stay very consistent.

If you want to bring things to the next level and use a more reality accurate camera in cg, different lenses also tend to have different apertures which is marked in f-stops. So a specific lens may only allow for a limited number of f-stops. The aperture controls how much light enters the camera (so how bright the image will be) as well as the depth of field (how blurry the background is). Again, more detailed discussion of aperture should probably have its own tutorial since its a complex topic. But for a true lens package, you should limit yourself not just to specific focal lengths but each focal length should be limited in terms of aperture. You can find this information out by looking up real world lenses and see what sort of aperture they tend to have.

For extra bonus points, each lens would also have a specific distortion, for example, wide angle lenses tend to have some degree of barrel distortion, and some telephoto lenses tend to have pincushion distortion. But not all cg cameras allow you to modify the distortion on the lens.

Talking to some experts, I found out that many of my favorite films from the late 70s, early 80s were shot on Panavision cameras. For example, The Empire Strikes Back and Indiana Jones And The Temple Of Doom was shot on Panavision C Series Anamorphic Lenses. A little more research shows that this lens package used for these films included:

Panavision C Series Anamorphic Lens Package:
20mm, 30mm, 35mm, 45mm, 50mm, 60mm, 75mm, 100mm, 150mm, 180mm

These are all fixed lenses (Prime Lenses) BTW, which means they only have one focal length each. You can of course throw a zoom lens into the mix, which will give you multiple focal lengths, like say a 36-82mm lens. Although many films from that era didn't use zooms, and used Fixed Lenses only. For at least some info on what your favorite films were shot with (although lens focal lengths are not included), feel free to check out http://shotonwhat.com/.

The standard 3dsmax camera actually has a lens package built in to the tool, see below...



So you have a preset number of lenses, or you can adjust the focal length above to be whatever you want. I wish there was a simple way to customize this lens package, as it would make things way easier.

Knowing what lens package was used on a film can also help you if you're a VFX person. Knowing what lenses were used for what shots makes it far easier to replicate these real world cameras in the virtual world (which is the process of matchmoving). And if you're adding some full CG shots to the film, it's best to stick with similar lenses to the ones used for the live action shoot, to help blend your completely virtual shots with the practical shots.

So next time you're doing a short CG film, and you've done a little research into wide angle and telephoto lenses, and in what situation to use them, consider going one step further and make yourself a 5-10 lens "package" of specific focal lengths, and stick to using those lenses for your virtual shoot, only deviating if absolutely necessary. Or to go one step further, have each lens have a specific focal length, specific aperture range, and a specific type of lens distortion.

Unless of course the goal is to make something not of this world, in which case all bets are off :)


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