Can I slo-mo 1080/24P?

I

Indyreel

Well-known member
I've shot my entire feature length film with the GH1 in 1080/24P to prepare for theatrical distribution and to insure that theatrical exibition is a high quality image when projected onto large cinema screens.

But...

Now I have to shoot the ending segment in slow motion and don't know how to insure top quality for the big screen.

Hopefully someone out there can help me make the right choice.

1) Can I slo-mot 1080/24p footage in post?

if not, then

2) If I shoot 720/60p at shutter 1/120 will it be noticably lacking in appearence "on the big screen" compared to the 1080/24p footage?
 
Indyreel said:
1) Can I slo-mot 1080/24p footage in post?
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Surely, but it doesn't always look good. You can double frames or blend between frames or even interpolate between frames based on motion vectors but the result varies.

Indyreel said:
2) If I shoot 720/60p at shutter 1/120 will it be noticably lacking in appearence "on the big screen" compared to the 1080/24p footage?
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Nope, it will pretty much look the same there is only some minor loss in resolution and almost nobody will notice.
 
I have been shooting (PAL) at 50fps both 720 and 1080... am i missing something here? Should 720 always be shot at 120 fps?
 
1) Yes, but it won't look very good. Depending on what you're shooting, you can use twixtor or AE to interpolate frames (create the in-between frames) when slowing footage down. This generally looks alot better than simply blending frames but only works on some subjects. You'll need to shoot with a faster shutter though, to get nice sharp images for the interpolation to work with.

2) Depends on your final output resolution/medium. I can't answer that too well because I've never seen footage from my GH1 on a large screen.

Personally I'd shoot 720p but my stuff is all destined for DVD so the resolution hit isn't as noticable. You could try and borrow/buy & return the next day/rent a TM700 and use it for the final scene so you can shoot 1080p60.
 
the doc: fps means frame per second. If you're talking about exposure, use seconds (1/120s).

To answer your question, if you use to shoot your footage 1080p25 1/50 and want to slow-mo using 720p50, then you should use 1/100 to achieve the same look.
 
divide said:
the doc: fps means frame per second. If you're talking about exposure, use seconds (1/120s).

To answer your question, if you use to shoot your footage 1080p25 1/50 and want to slow-mo using 720p50, then you should use 1/100 to achieve the same look.
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Ah yes - thanks for setting me straight.

If you DONT intend to slo-mo your 720p should it STILL be shot at 100 (something about 180degree shutter that I don't understand) or is there no problem at 50? I certainly have been happy with the 720 picture I was seeing but....
 
I think people who say that they can't see the difference in detail of 720p vs 1080p are insane, lacking a real 1080p monitor, or don't have their contacts in / glasses on.

There is a huge difference in detail and resolution from 720p to 1080p - technically double the detail, although we can argue that slightly because the GH1 itself technically only truly resolves about 600 lines on a test chart, but looks like it resolves a lot more in real world shoots.

The amount of detail here would look like mush in 720p:
http://blackout.com/clients/top-of-ghostbusters-building.MTS


The first think about shooting 720p is that is just does not look like film looking 24p when you convert it from 60p down to 24p.... 2ndly it looks 'mushy' to me on a really big screen.

However, for slow motion shots it does work, or for fast camera movement scenes to reduce jello, and especially if it is a medium or rather close shot of the subject no one will ever know except the pros.

So you shoot 720 60p, then put it into a 59.94 1920 x 1080p timeline, leave your regular 1080 24p footage alone, and on the slomo parts select smart resample, and slow it down to .4 in sony vegas, then render to a 23.976 final master and viola, you have your original 1080p detail, along with your slomo up rezzed to 1080p, and most people will not notice the resolution change during the slomo part, nor the lack of a film look because the slow motion helps fix that.
 
Blackout said:
....although we can argue that slightly because the GH1 itself technically only truly resolves about 600 lines on a test chart, but looks like it resolves a lot more in real world shoots.
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Has this been tested (or re-tested)? I understand that this is what it was before the hack but since then things have really "cleared" up.
 
Blackout said:
I think people who say that they can't see the difference in detail of 720p vs 1080p are insane, lacking a real 1080p monitor, or don't have their contacts in / glasses on.
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I think that's putting it a bit strongly, but I'm sure you're right that on the big screen at least you'll be able to see some difference between 720 and 1080. But I think I'd much rather have 720/60P for slomo than 1080 slomo in post, it just never looks that good.

Steve
 
Ian-T said:
Has this been tested (or re-tested)? I understand that this is what it was before the hack but since then things have really "cleared" up.
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The difference wouldn't show up in a test chart scenario.

The hack will only make a difference where compression was compromised in the stock GH1 (basically normal shooting conditions or anything with movement, where poor compression was the limiting factor) . Test chart shooting conditions are static, and even the stock GH1 compression is unstressed. The hack isn't changing the optics.

I agree with the above comments, that slomo in post is usually poor . But certain shots with limited motion can work well with slomo in post, if done properly with mattes
 
steve phillipps said:
I think that's putting it a bit strongly, but I'm sure you're right that on the big screen at least you'll be able to see some difference between 720 and 1080. But I think I'd much rather have 720/60P for slomo than 1080 slomo in post, it just never looks that good.

Steve
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I agree to use the 720p for slomo, but that's it. I would never shoot my whole project in 720p like many people do. It really is a HUGE difference in detail and noticeable more and more as you go up in screen size. DL and watch the clip I posted and pause on either the city or the brick building behind me. Look at the detail... you can clearly see every little brick's diagonal lines without aliasing or moire. In 720p, both the city and bricks look mushy and soft and you lose that detail.

Also, shooting 1080p 24pn at 50 shutter outside by far has the most film looking motion characteristics. I can instantly spot 720p 60p converted to 24p through either conforming or a more complex process but in slowmo, 720p mixed with 1080p footage works great. Most music videos go the route of shooting everything in 720p and they look OK but the shutter and motion cadence looks strobey and videoish to me.

I am shooting a music video the first week of September and plan to shoot 1080 24p mixed with upscaled 720 60p slow motion and the above described method in my first post is how I will go about it.

I am editing on a PC and in vegas 9e though workflow will be different in final cut or premiere.
 
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Blackout - If you're going to upscale, I would consider using something other than Vegas to do the scaling.
 
No , I was referring to using real upscaling algorithms, not just a resize to 1080

You will find it sharper with less aliasing introduced . Vegas uses a simple bicubic resize.

If speed is your major concern, then carry on - I was just suggesting other options for better quality

Cheers
 
I believe vegas 9e has a drop down with a variety of different settings... which would be the best one to choose? What are you editing in? Remeber I am on a PC so final cut isn't really an option unless I have to deal with it for a client on my old clunky mac.
 
Blackout said:
I believe vegas 9e has a drop down with a variety of different settings... which would be the best one to choose? What are you editing in? Remeber I am on a PC so final cut isn't really an option unless I have to deal with it for a client on my old clunky mac.
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Hi - I use PC primarily too, but I was referring to 3rd party tools that do upscaling like instant HD, avisynth, etc... You will find most NLE's will be soft with their scaling . You cannot change the algorithm in vegas 9, but in cs5 you can make it little bit better by using MRQ during your renders

They typically do more than just upscale , they usually introduce antialiasing filters , some sharpening, some grain. Most work spatially (frame by frame) , not temporally (don't account for information from adjacent frames) , so you could just as easily use things like genuine fractals, or photozoom that work spatially on photos

No upscaling algorithm can replace lost details. I.e. a 720 image upscaled to 1080 will NEVER look as good as a true 1080 image (assuming that 1080 image was shot with an imaging system that can capture true 1080)

I think there's a couple of threads dedicated to upscaling , so you might want to have a look

Here is a quick example to demonstrate:

original
2m2yr6w.jpg



vegas 2x scale (notice the aliasing introduced)
9j2mmx.png



avisynth 2x scale using spline36 algorithm, nnedi2 antialiasing
aab1uh.png
 
Ahhhh... very interesting Definitely see the difference there although I haven't really seen those artifacts (at least not that badly) in my upscaled stuff in vegas... but I'll look into those other tools since this next music vid I'm doing is going to be a mix of about 75/25 1080p 720p.

Thanks for the tips.
 
the doc said:
Ah yes - thanks for setting me straight.

If you DONT intend to slo-mo your 720p should it STILL be shot at 100 (something about 180degree shutter that I don't understand) or is there no problem at 50? I certainly have been happy with the 720 picture I was seeing but....
Click to expand...

http://en.wikipedia.org/wiki/Rotary_disc_shutter

I usually do my 60fps slowmos at 1/120 shutter, it gives you a more smooth motion after all, 360º shutter is ugly!
 
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