The Panasonic GH2, DSLRs, and Funky Frame Rates For Creative Effect
Sunday, December 5, 2010 at 6:52PM 
Many folks wrote in the comments of my Canon 60D article something to the effect of “what about the upcoming Panasonic GH2?”
The GH2 is not yet available. Despite having been briefly up for pre-order on both Amazon and B&H, it is now listed as unavailable on both sites. That, and that it is not a DSLR, excuse it from inclusion from an article titled “HDSLR Shopping.”
However, the GH2 does look very exciting. I had been thinking of selling my 7D and buying a 60D, but I might wait and get a GH2 instead. My only real trepidations about that are covered in my post about the Panasonic AF100, where I discuss the slightly-smaller-than-35mm imager and the dearth of fast motorized lenses.
In brief, if you’re not familiar, the GH2 is a mirrorless interchangeable-lens camera in the Micro 4/3 format. Being mirrorless, it is not a DSLR — but the desire to compare them is natural. Like our Canon HDSLRs, it is a stills camera with a video mode. What it promises over the Canons and Nikon HDSLRs are cleaner, higher-resolution video images and Panasonic’s signature attention to the needs of video shooters, with features like touch-to-focus, on-screen audio level monitoring, “Cinema Mode” color profile, clean HDMI out, and even a 1:1 crop mode — which allows you to take an HD crop out of the center of the frame, effectively acting as a digital tele-extender with no light loss.
The predecessor to the GH2, the GH1, broke my heart by suffering from compression artifacts so egregious that I resorted to rhyme. By all accounts, the GH2 does much better in this area, although it joins a sadly crowded category of cameras that seem to do everything right and then commit all your hard work to a codec just barely sufficient for the task.
One of the things that piqued my interest about the GH2 was its “Variable Movie Mode,” which purports to allow over- and under-cranking. Turns out this feature is not very exciting in practice. Panasonic’s site shows what looks like a broad array of speed options, from “80%” to “300%.” However, it soon becomes clear that the increments, 80, 100, 160, 200 and 300 percent, are significant in that they represent frame rates likely to be available on almost any camera.
If your base, 100%, is 24 fps, then 80% is 30 fps, 160% is 15 fps, 200% is 12 fps, and 300% is 8 fps. My 7D has 24 and 30, and if I wanted 15 fps, I’d just shoot at 30 and double in post. Same with 12 and 24. And if I wanted to shoot at 8 fps for some unprecedented reason, I’d shoot at 24 fps and speed up 3x in post.
The 7D and 60D shoot at 60p in a heavily artifacted 720p format (which I nonetheless used indulgently in Brick & Steel). The GH2 can shoot 1080i60, which you could de-interlace carefully and create 60 fps slow-mo (detailed instructions for this are included in The DV Rebel’s Guide). In both cases you’d better watch out for high-frequency horizontal detail in your frame, because it’s going to be dancing the night away. So the GH2 is not really offering much more than the 60D in the variable frame-rate department.
UPDATE: The GH2 also shoots 720p60, which is the better choice for slow motion.
What filmmakers really need are funky frame rates all around the home-base of 24, and overcrank rates that can be cleanly sped up in case you discover in the edit that your shot wants to be more John Ford than John Woo. Here are some of my favorites:
- 24p is our everyday frame rate for sync sound and business as usual.
- Undercranking by only one tick to 23 fps speeds up motion so unnoticeably that it’s recommended for almost any fight scene not featuring Tony Jaa.
- After lunch, when everyone’s moving a bit slower, you can shoot fight scenes at 22 fps. You can even drop down to 21, but things might start to look a bit keystone cops at that point.
- [UPDATE: See the comments for a discussion of achieving these undercrank speeds in post, if your camera does not offer them]
- I have seen car and motorcycle drive-bys juiced-up by undercranking as far as 12 fps. Only works on smooth surfaces.
- Moving into overcrank territory, shooting 30 fps for 24p playback can give scenes an almost imperceptibly dreamy quality. Everything feels a bit lighter and floatier, but you’re not telegraphing “slow motion” to the audience. Many of the behind-the-scenes shots in Brick & Steel were shot at 30.
- If I’m worried that 30 might be noticeable, I’ve been known to shoot at 27 fps, which always sends the camera assistant scrambling to make up a new velcro-backed number for the slate.
- 36 fps is exactly 1.5x slower than normal. The audience will know something is up, but it’s still subtle.
- In fact, so is 48 fps. You’d think that half-speed would seem slow, but it doesn’t feel as slow as it sounds. 48 is handy because you can double it in post and be back to real time.
- Since my 7D has 50 fps, not 48, I’ll use that when I think I might want to double back to real time.
- Many cameras top out at 60 fps, which is fine for slow-mo, but it’s hardly Inception-grade slow-mo. Still, it’s nice. See the flyswatter in Brick & Steel.
- Better is 72 fps. 72 is just a pretty slow motion speed. And conveniently, you can 3x it in post and you’re back to real time.
- I shot some fight scenes in The Spirit at 88 fps. Why? Because it’s a nice slow speed, and if you 4x it in post, you’re back to 22 fps. So I could ramp from amped-up speed to dramatic slow in the same shot.
- 120 is another handy speed at 5x real time. And beyond that, you’re into frying-pan-to-the-face slow motion effects.
OK, we’ve gone a bit off the topic of the GH2. But this is the ride my mind went on after getting excited about the “Variable Movie Mode” and then realizing what a non-thing it actually is. All it really buys you is the slight convenience of not having to conform different footage speeds in post, and the nicety of being able to preview these speeds in on-set playback.
The GH2 is going to be similar in price to the 60D, i.e. cheap. You’re going to have to spend more, like AF100 or Sony F3 money, to get the funky frame rates I list above, and even in those cases, you’re topping out at 60 fps (which, in the case of the Sony, is only available at 720p). I’ve completely lost track of the various cameras that Red is busily making, but hefty overcrank rates are something they promise, at a proportional price.
Meanwhile, If you, like me, are excited about the little GH2 despite its shortcomings in the frame-rate department, check out what Phillip Bloom has done with his pre-release model.
And I’ll let you know if I find one under my Christmas tree.
