There are some exciting new camera options out there these days, ranging from inexpensive, large-sensor hybrids from the likes of Panasonic and Canon to groundbreaking high-end digital cinema rigs from folks like RED and Arri. When contemplating buying or using these cameras, one has many resources to evaluate things like focal length equivalencies and depth of field. This chart from Barry Green is a great example — it’s extremely helpful and the kind of thing you could refer to again and again.
In fact, if you’re like me, you’ll need to refer to it again and again, because there’s nothing really intuitive about it. It’s a bunch of numbers. You might find yourself staring at it and thinking, “Yeah, but what kind of shot can I actually make with these camera/lens combinations?”
Read down the thread on DVXuser and you’ll see one member exclaim with glee that with only three Panasonic zoom lenses, he can cover every focal length from 7mm to 300mm on his Micro Four-Thirds (MFT) rig. Barry quickly points out that this is true, but at undesirably slow apertures. The poster is, I’m sure, left scratching his head, trying to grok just how these slower lenses are going to affect the cinematic look and feel of his shots.
You can feel my own frustration with this in my article on the Panasonic AF100. I discussed there the dilemma of MFT — is it “big enough” for cinema? Yes, but if you want cinematic DOF, you’ll need fast lenses, faster than most of what Panasonic makes.
Another example — you might be looking at the recent demonstrations of the fixed-lens RED Scarlet and wondering just how much DOF control you’ll have with an ƒ2.4 lens on a 2/3” sensor.
All the charts and sensor-size comparison images and spec sheets won’t answer the question: “Yeah, but what shot can I make?”
So I’m introducing a new Prolost feature designed to help answer that question. It’s called the Shot You Can Make (SYCM) Simulator, and it’s sort of a 3D “Marcie” for focal length and depth of field. Here’s what it looks like:
I started with a shot from a movie called 12 Rounds. Directed by Renny Harlin, 12 Rounds is an action flick set in New Orleans and starring WWE’s John Cena. It’s the kind of movie you can rely on to contain the kinds of shots you see in many movies — in this case, a guy (Cena) with a gun. The focus is on Cena’s face, the gun is slightly soft, and there are a few big, boke-liscious out-of-focus lights in the background.
12 Rounds was shot with Panavision cameras on Super 35mm film. My guess is that this particular shot was made with a 125mm Panavision Primo at ƒ2.0. Based on this estimation, I simplified the image into cartoon-shaded layers and split them out in 3D in Adobe After Effects, essentially recreating a simplified model of what was in front of the lens that night. Using a lens blur plug-in rigged with expressions, each 3D layer gets the correct amount of defocus for its distance from camera. The result is a simulation of the shot with accurate angle of view and depth of field.*
The shot contains a number of recognizable things, like a man, a hand, a gun, and some distant lights. If you’re familiar with your camera — any camera — you can probably easily imagine what kind of shot of this setup you could make. But what about a camera that you’re not familiar with?
The Shot You Can Make Simulator allows me to place any camera I want, with any lens, at any stop, into this same scene, and re-photograph the virtual scene with that rig. In this way it provides a real-world-ish benchmark for the kind of lens performance that matters most to filmmakers:
- What’s the angle of view, i.e. how wide or telephoto is this lens?
- What kind of depth of field performance can I expect? I.e., what will be my ability to isolate my subject from the background using focus?
Here’s an example. Simulating a Canon 5D Mark II with a 50mm lens at ƒ1.4, you can see that I’ve had to move closer to my virtual Cena to achieve similar framing. His hands appear larger, and much softer. The lights in the background are still blooming, but not as much. Although we’ve opened up about a stop and focused closer, we’ve also gone wider in AOV, so our ability to make big circles in the background has diminished.
Another example, this time simulating the shot you might make with a Canon 5D Mark II using the Canon 70–200 F2.8 II IS, at maximum zoom:
Note that we now have a slightly narrower Angle Of View than the Super 35 125mm baseline, so we’ve stepped back a bit to maintain the framing. But despite focusing longer and stopping down, we have a much larger image sensor on the 5D, so we maintain the same “feel” in terms of the softness of the gun barrel and the size of the background boke.
Now, if someone tells you that 200mm on a 5D Mark II is a decent rough match for 125mm on Super 35, that’s useful information. But unless you’re a Cybog Killer from the Future, you might have a hard time getting a sense of how all the other factors will balance out — slower lens, but larger sensor, but longer focus, but more money left over for tacos.**
I was trying to explain to someone the other day why I felt that the MFT zooms Panasonic has on offer are not very sexy. Maybe this will help — here’s the same shot at 140mm ƒ5.8, the max zoom of a popular “do it all” MFT lens from Panasonic:
Even though we’re zoomed way in, tighter than the baseline shot, we can just barely soften the background, and the gun is razor sharp. Interestingly, the Shot You Can Make with the Panasonic 14–140mm is not unlike the Shot You Can Make with a Canon HV20, which has a tiny sensor by comparison, but a surprisingly fast lens. Here’s the HV20 making the shot at its max zoom of 61mm, ƒ3.0:
The similarity between these images shows that you can very easily slap a lens on a MFT camera that will completely undo any perceived DOF advantage of the large sensor. To me, this is useful information. If you agree, I’ll use the SYCM Simulator to profile lenses and cameras I discuss here.
* My respect for you the reader demands that I generally avoid disclaimers, but in this case I would like to point out that this is all guesswork on my part, from the original lens used to the dimensions of the set. And I could very likely have my math wrong on any of the DOF calculations too. Please let me know if anything jumps out at you as wrong.
** Tacos have not yet been integrated into the SYCM Simulator.
Update
on 2011-01-13 18:28 by Stu
Be sure to also check out this camera/lens comparison tool from Abel Cine. I’d been looking for the link when writing this, but luckily Jason Wingrove helped me out on Twitter.
Update
on 2011-01-20 05:35 by Stu
Those of you asking about a mobile app version of the SYCM Simulator, be sure to check out this follow up post.