Faking 120fps with 60p?

SJX

SJX

Veteran
I need to shoot 120fps with a camera that max. at 60p. Any camera and post tips to get best results? Should I use standard shutter speed or something else? What is best post workflow? Thanks.
 
The only thing I can suggest is a plugin like Twixtor. It only works on specific scenes though (eg a fairly plain background). You'll want to shoot a faster shutter speed in order to get the best results from the post processing. But there's only so much it can do.

There really is no substitute for actually shooting at a higher frame rate. If 120fps has been specifically requested, there's really no way to effectively and reliably fake it.

What exactly is it that you need to shoot, and where is the 120fps requirement coming from?
 
The other day I shot a lot of 4K 60p on the FS7 and wanted to make some slow-mo out of it in Vegas Pro NLE. So, I started stretching it out on the timeline and was surprised that it stretched it out past double-length, since my project was 30p. I think it made it 4x slow-mo. Played back nice also.

To your question. Something I do with my footage shot in 120p when editing, is I drop it on the 30p timeline and stretch it out for 4x slow-mo, then I render it out in an intra frame format, rather than a long frame format. Then I bring it back into the project and apply any color-corrections, stabilizing, etc. to it. I never did a serious test to see if it makes any difference, but it just makes sense to me to do it this way.

Regarding Twixtor.... I shot something in 4K 30p and later wanted to slow it down. It had a complex background; white-capped ocean waves and lots of rope netting involved. Going to a 2x slow-mo was rather nice looking. So I pressed on to 3 and 4x. At 4x, it was not too good, got some weird shape-shifting/morphing effects. I backed off to 3x and there was still some weirdness but not too noticeable. Conclusion, I would give it a try for 2x slow-mo before just writing it off. Never know. I think they've improved Twixtor over the years, seems better quality to me than about 6 years ago.

Mark
 
Thanks for the answers. Maybe I should invest in a 120fps camera then. Can anybody recomend something I can get really cheap used? HD is enough and doesn't need to be 35mm. Smaller sensor is probably better. But low light can't be too bad. The smaller the better too. But gopro has fisheye effect so not good. It can be fixed zoom lens but must be at least as wide as 18mm or 20mm s35. Good image is a must.
 
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If you only need 120 FPS for one shoot, you might as well rent a camera instead of buying another. A used point & shoot camera would probably be the cheapest option outside of renting, but I don't remember which point & shoots do 120 FPS or if they'll record for a long enough duration; you can find video specs. on DP Review's camera data base.
 
Rent doesn't work. I will need it many times and it will get more expensive. I looked at specs but this is different than hearing from people who have used the camera.
 
I like my FDR-AX53 for most of my handheld high frame rate recordings. I have the FS7 for tripod stuff, as well as the FDR-AX100. Good things about the AX53: FHD 120P, 20x zoom, balance optical steady shot (BOSS) IS (fantastic!), long battery life, compact form factor. It also shoots 4K (UHD). I like that when shooting 120p, it saves it as 120p, with audio recorded. This means you can slow it down in your NLE to 2x, 3x 4x or keep it 1x real life speed. It keeps auto focusing and adjusting for exposure during HFR recording.

What it's missing (for my uses): lacks manual controls. There are some manual controls, but for all practical purposes, it's really an all-auto camera. No ND filters. It has a 1/2.5" CMOS sensor. Not great in low light. Doesn't have a "normal" LANC jack. It has LANC wired remote provisions, but it's not a standard jack, so if you need that, ask and I'll give you details. Zoom, record start/stop can be controlled by wired remote, maybe more.

It's a real camcorder and the rocker zoom works good enough for creeping or crash zooms but not much in-between. I think the 120p image quality is fine. Price is $1,000 new. I bought two of them once I found how great the IS works. I think the next step up would cost 3x as much but give you a larger sensor and all those manual controls (but no BOSS).

The FDR-AX100 has a 1.0 inch-type sensor, but does not have the BOSS IS, and 120p is only 1280x720. It has good manual controls: iris, shutter speed, gain are all independently adjustable, or make any combination of manual and auto setup you need. Has built-in ND filters.

https://www.bhphotovideo.com/c/product/1211905-REG/sony_fdrax53_b_fdr_ax53_4k_ultra_hd.html
 
New Releases to watch:

There are some new Sony and Canon cameras coming out (aren't they always?) and as a replacement for my FDR-AX100, I'm looking at the Sony PXW-Z90. 1 inch type sensor, 12x optical with clear image zoom of 18x (4K mode) and 24x (HD mode). Has XLR inputs, hybrid A/F, better EVF, normal LANC remote jack. Manual controls and more. HFR 120p. I want to be able to cut better with the AX53 and its FHD 120p, so that's the main thing. Improved A/F is also welcome. Priced at $2,800. Two lesser models are HXR-NX80 for $2,300 and the FDR-AX700 @ $1,900. I just need to see the quality of the Clear Image Zoom mode since I take full use of the 20x on the AX53 and will need to push the Z90 past its 12x optical zoom limit.
 
I was thinking Panasonic HC-V750. I think the FDR-AX53 is the sony equivalent? AF with FDR-AX53 hunts a lot? So no MF? Iris hunts a lot? Low light is not great. But it's like FS7 closed to what? F8? Maybe HC-V750 is more sensitive since is HD only.
 
Probably too expensive. Or I would maybe buy A7S which I think is not much more used. Also if I can find smaller chip is better.
 
You can always stop down...I would avoid the fixed-lens cameras as most are extremely dated in quality.

Maybe a used GH4 could work between $600-$700. There is a used one at B&H for $673.
 
SJX said:
I was thinking Panasonic HC-V750. I think the FDR-AX53 is the sony equivalent? AF with FDR-AX53 hunts a lot? So no MF? Iris hunts a lot? Low light is not great. But it's like FS7 closed to what? F8? Maybe HC-V750 is more sensitive since is HD only.
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I see the HC-V750 is discontinued, but going by the newer replacement, the HC-V770, one difference is the Panasonic does not have an EVF, just the LCD. I don't think anything beats the BOSS IS of the Sony. So, depends if doing handheld work whether those two things matter to you. FS7... I just mentioned that camera to say that even though I have it, and it does HFR, the AX53 gets more hours of HFR on it, just so easy to use and does a nice job. I'm highly recommending the AX53. I nitpick about the A/F. Can't think of any other camera I have that can do better A/F under conditions of shooting cars on a race track or jets in flight. Something I shoot a lot of. You can assign the manual ring to control your manual focus, or you can use the touch screen to choose an object to focus on and it will do a decent job. I leave it in A/F 90% of the time. Low light is decent, just not a strong point with a camera with this small of a sensor. My Canon 6D with a 24mm f/1.4 does a good job of seeing in the dark, where this AX53 would not work at all. But for "reasonable" dimly lit scenes, it's fair. It doesn't suddenly start to break up the image into an ugly mess at the first sign of low light. I set the gain max to 24dB, and at that point there could be some pixilation. You said you wanted a small sensor cam, so I think with all the other attributes, this is a good choice. If I had found another 120p FHD capable camera, I'd already own it. I do not like shooting video on any kind of dSLR, bridge, P&S cameras. I have the Sony RX100 MK4 and it shoots nice video, but it's really just a BTS camera, meaning I intend to use it to take photos and video of my other cameras. It's also my pocketable P&S when needed. Other people can manage very well with those dSLR and other cams, just not for me. I want a proper zoom rocker and a barrel body to wrap my hand around.
 
I'm thinking I will have to go 35mm afterall. Probably even full frame. Reason I wanted small chip is because I want deep focus. But now I'm thinking for low light buying A7S and stopping down will be better than using small chip camera. Small chip has bad low light. 120fps needs 5 times more light. If camera suck in low light at 24p it will suck harder in 120fps. I need shoot night streets.
 
Shooting mixed-light (ie city street) scenes at night is a nightmare for slow-motion.

Basically, once you go past 60p, your shutterspeed will no longer be in sync with the electrical grid (60hz) and you may get all sorts of flickering lights in all your footage. Combine that with the variety of mixed lighting types you typically get in night exteriors, and you'll virtually never be able to eliminate flicker. Worst of all you won't actually notice this until you play the footage back in slow motion - so you might record something thinking it looks great in the viewfinder, only to watch it back later and realise all of your footage is ruined.

This is without even considering the fact that, as you said, you'll need 5x as much light to shoot 120p - and it's hard enough to expose for 24p using available light at night. You'll end up with very noisy images if you're shooting slow motion at night. And it also means deep focus is out of the question - you'll want to be shooting at f/1.4 to make the most of the available light.

Unfortunately what you're asking for (slow motion, low-light & deep focus) does not exist in any camera today. I'd recommend you save your money, and instead figure out how you can shoot your scenes differently so that all the factors are not working against each other.
 
The a7SII would be the best fit...1080/120p @ ISO 50,000 or so with f/8 on a decent lens should get you going. Flicker will depend on the lights being used, but I don't think there will ever be a scenario where you're pointing the camera at a scene with a bunch of lights and all of them don't flicker (at least one will).
 
NorBro said:
The a7SII would be the best fit...1080/120p @ ISO 50,000 or so with f/8 on a decent lens should get you going. Flicker will depend on the lights being used, but I don't think there will ever be a scenario where you're pointing the camera at a scene with a bunch of lights and all of them don't flicker (at least one will).
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This is what I'm thinking too. Don't know about flicker. But A7S sees in the dark. So I was also thinking I could shoot 120fps with f8 and have no problem. Is there advantage for A7SII over A7S for 1080p?
 
I have the a7sII. It does see in the dark, but it does lose fidelity due to noise reduction. Night time at 120fps will render some pretty soft results...not ProMist soft, like wobbly blobs, soft.

Flicker aside, if you switch to s35 mode, you can use some fast photo glass, like f1.4 with a speedbooster. This will get you some fidelity back, but not deep focus.

I'd actually see if you know someone with a FS700 with an Odyssey 7Q. Again, use a speedbooster, and shoot 120fps at 2K RAW. This will be pretty affordable and will render great results.
 
SJX said:
This is what I'm thinking too. Don't know about flicker. But A7S sees in the dark. So I was also thinking I could shoot 120fps with f8 and have no problem. Is there advantage for A7SII over A7S for 1080p?
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a7sII has 120p @1080...a7s has it @720.

I think you could get pretty decent results at a lower ISO than 50,000 without losing much quality. You probably don't want to turn your night into day; just be able to have decent exposure.
 
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