Canon 7D footage; frame rate question

Hi folks,

I'm editing a doc that is being shot on the Canon 7D, mostly in 24p. The DP and director have shot material in 30p and 60p, for B roll stuff, and want to keep doing it, but I'm concerned about the results I'm seeing in FCP. I've been running some tests, and have used Cinematools to conform the 30p footage to 23.98 (our editing timebase), which, naturally, provides a mild slo-mo effect when brought into the timeline. The 60p stuff will behave the same, I'm assuming, but I've only been testing the 30p stuff.

Now, I'm going to have to conform the 30p stuff back to a 'normal speed' in FCP at times, which I've tried by simply speed-shifting the clip to 125% in me sequence. When I do this, I feel like there is a mild jitter to the action when the frame blending is OFF, and an obvious motion blur when the frame blending is ON. I have the motion estimation at BEST in the sequence prefs, btw.

I guess my question is...do we gain ANYTHING by shooting in 30p, if I'm going to eventually need that footage to play back at a 'normal real-life speed' in 24p? They see it as an artistic choice, but I ONLY see the purpose if they are wanting a slight slo-motion feel, or want the slight jitter of 30p with 'frame blending OFF', to give an edgy look. A similar question: is shooting at 30p, conforming the footage to 23.98 (via Cinematools), and giving it a 125% speed shift in FCP the SAME AS shooting 30p, NOT conforming it, and viewing the same footage in a 29.97 Sequence?

They're thinking they'll shoot the rest of their B roll in 30p, and it makes me nervous to have all of it like that down the road, and I'm trying to make a recommendation about it. Any advice is greatly appreciated. Thanks!

Greg

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do we gain ANYTHING by shooting in 30p, if I'm going to eventually need that footage to play back at a 'normal real-life speed' in 24p?

Depends on who you ask. Shane Hurlbut is a huge fan of shooting 30p and then optical-flow retiming back to 24p with Twixtor. He says it takes the sharpness off. I think he's nuts, but he's been the director of photography on approximately infinity-times more feature films than I have, so you judge.

Basically, if you're going for an "artistic look," then decide what look you're going for, and achieve it the proper way. If they want a slightly dream-like quality, then shooting a slightly overcrank is exactly the right way to do it. You might shoot 28 or 32 on a cinema camera; shooting 30 on a DSLR is a fine approximation.

On the other hand, if you want a short shutter, then shoot with a 1/60 or 1/75 shutter at 24. That way you don't introduce all the optical crap you get from doing a synthetic retime, while still capturing that vaguely hyper-real look a short shutter gives.

Bottom line, though, is that the client calls the ball. If you run some 30p stuff through Twixtor or Compressor and they like that look, then hey, who are we to argue with 'em? Just make sure they know that it's something like an hour per minute of rendering time, or whatever the ratio is on your system, so they know not to expect you to drop those shots in in real time.

Hey, Kingg33. What does the 24p that is shot in the Canon 7D look like in FCP. I'm assuming you're editing in a 23.98 timeline, right? Does it look like 24 fps shot in film? Are you watching it on a monitor that projects 24 fps or 29.97?

See, I'm also assuming that the reason they're shooting with a Canon 7D is because they eventually want to generate a 35mm print, am I right? Or is it just an artistic choice and a matter of having low visibility on location?

Because from what I have read on LAFCPUG, it would be best to shoot everything as 24p. Then if you wanted slo-mo you could do slow-mo much more effectively in FCP or with a plugin.

I think this is a very important subject by the way, so I hope you will give a few more details as to exactly what frame size and shutter speeds they are shooting.

Thanks for the notes Jeff. I'll run it by them. Very helpful.

Filmman, the 24p stuff looks great in FCP, although I'm just viewing it on a laptop Macbook Pro monitor. I don't know if they want/need a 35mm print down the line. The footage looks much better than most video cams because of it's DSLR/lenses/size of sensor/general Canon-badassness-of-tonal-range-ness qualities, so to my mind that's reason enough. It's a newish camera, and my first project with it, so I'm learning it's pros and cons.

Now, I'd disagree with the 'shoot all in 24p and slo-mo in FCP' notion. Shooting in 30 or 60p, conforming to 23.98 in Cinema Tools, and dropping in FCP I can tell you right now is a more convincing slo-mo than FCP's internal method. That I'm learning with this project, and I've slowed footage down on tons of projects in the past. Now, whether another program can do a better job than FCP at that, so that 'just shoot everything in 24p' makes sense...that I don't know. I can't imagine it looking better than the 60p stuff I just imported. It's the nicest slo-mo stuff I've seen in FCP yet. No 'frame blending' blurs or anything. Looks real nice.

G

Yeah, that's pretty much correct. You're never going to get a synthetic retime, not even with optical flow, that matches a proper overcrank. There are situations where you have no choice, and there are shots where it's really tough to tell the difference, but you just can't get the same results with frame blending or motion estimation.

One thing to watch out for is trying to cut between 1080p24 and overcranked 720p. I've done that a few times and it's generally fine, but it always bugs me that the shots that started out as 720p60 are so much softer than the 1080p24 stuff. This may be me being extra-picky, though.

Hm, that's an interesting point about the 720p60 material looking soft. I know for a fact they aren't thinking about that, so I'll mention it. I do think they intend for this piece to have a theatrical run, so that's important to consider.

G

You probably won't spot the difference if it goes to 35. By the time you record a neg, then make an IP, then an IN, then your release print(s), you've have lost the extra resolution the 1080 material had anyway. It varies depending on stock and stuff, but the rule of thumb is that a 35mm print ? not negative ? when projected in a typical theater has more-or-less the same resolution as 720p. Tons more dynamic range, obviously, but in terms of sheer resolving power, a theatrical screening is less than you might suppose.

You might be able to spot the difference on an HDTV, though, since the 1080 material would be full-resolution and the 720 would be up-scaled. Again, it really depends on your own personal eyeballs. I don't like cutting between 1080 and 720 when I'm in the editing room two feet from my monitor, but from my couch at home I might not even notice.

Very interesting about the theatrical resolution vs HDTV. Thank you. You are clearly a fountain of knowledge. Much appreciated!

Yeah, I'm a fountain of somethin', all right?

You're right about the slo-mo, Greg. FCP or a plug in no way compares with good overcranking. It's just plain incorrect advice.

By the way - to reference Jeff's mention of Shane Hurlbut's views on Optical Flow and such, look up "red centre @ fxguide" in iTunes podcast - it's the 56th episode. Very entertaining interview.

The other point about Shane Hurlbut is when shooting on canon 5D he had no option than to shoot 30p where as the 7D has 24 and 25 fps etc. I'm sure when the new 5D firmware arrives next week enabling 24p and 25p he will not be doing any twixtor work.

Derek

Since we're on the topic, Stu Maschwitz has a very good example of what could happen in an optical flow based retime.

[prolost.com]



www.strypesinpost.com

I don't like cutting between 1080 and 720 when I'm in the editing room

Just ignore me while I react off topic, but when I read Jeff's perfectly on topic comment I was filled with the urge to note that in a quite different context I very much prefer intercutting temporally matched content vs HD resolution matched content ... given the option, anyway. Specifically when working with and for primarily interlaced content I find the temporal match of 1080i50 and 720p50 far more preferable than the resolution match of 1080i50 and 1080p25. I deal with an increasing amount of source footage coming from 7D and 5D camera's and the difference in temporal quality, to me, is always by far the most jarring thing.

Well, we're really talking about three different scenarios here:

1. Mixing interlaced and non-interlaced material. Don't do this; it sucks. (Blah blah sometimes unavoidable yes yes yes.)

2. Mixing material that was shot in the same format, but at different frame rates. Like say, 720p24 and 720p60. This works fine, and in fact is done all the time. As long as the shutter is locked to 180° always, you can shoot at any frame rate you want, and play back at your baseline frame rate (24p, say) to either slow down or speed up the action. Most of Lars von Trier's "Antichrist" was shot on Red at 24, but the entire prologue was filmed on the Phantom at a thousand frames a second, and it's beautiful. (The movie's also the only truly scary horror film I've ever seen in my life, but that's neither here nor there.)

3. Trying to hammer the square peg of one frame rate into the round hole of another. If a filmmaker goes out and shoots material at 24 and at 30 (or anything other than 24) and intends to have them both play back at 1:1, then he needs to turn in his union card and find another line of work or something.

The biggest challenge in the early days of DSLRs (like a year ago or whatever) was the shutter angle. When the 5D first came out, you couldn't lock the shutter when shooting moving footage. The camera would change the shutter angle (or shutter speed, I guess, since it's an SLR camera) to adjust exposure as you rolled. This was a nightmare, because you'd get wildly varying motion blur under different lighting conditions.

I believe this problem was fixed with a firmware update some time ago, and that it's never been an issue in the 550, 1D or 7D. I could be wrong, because I've never shot with any of those, but I think I read that someplace.

derek hillier Wrote:
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> The other point about Shane Hurlbut is when
> shooting on canon 5D he had no option than to
> shoot 30p where as the 7D has 24 and 25 fps etc.
> I'm sure when the new 5D firmware arrives next
> week enabling 24p and 25p he will not be doing any
> twixtor work.
>
> Derek

Actually Derek, the guys in the podcast i noted asked him that question, and Hurlbut said nope, he still plans on 30p and Twixtoring it to 24p rather than shooting 24p in cam. Go figure.

It should be noted that Shane is a very opinionated guy. Not that there's anything wrong with that. He's just a person of, y'know, strong convictions. Who has no qualms about expressing them. Definitively.

LOL - Yeah I definitely got that out of listening to the interview Jeff.

I reiterate the point that he's an accomplished cinematographer and I'm a guy on a couch. Like him, don't like him, agree, disagree, whatever ? he's more qualified than I am to express opinions on this stuff.

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Jeff
Well...

Bloody hell Jeff, I'm sure I specifically left instructions for you'all to ignore my response.

But I got to namedrop Lars von Trier. That's not the kind of opportunity a person can just pass up, Andy.