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FS700 Aliasing Issues in Slow Motion and Question on Blu Ray


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#1 Scott Goldberg

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Posted 02 February 2013 - 03:46 PM

Just bought an FS700. Extremely happy with it. I've been doing some test shoots. I've been noticing that on 120 fps ad 240fps or anything over 60fps, there is aliasing issues on over-exposed whites when let's say behind green leaves, tree branches, etc as well as on glasses, some patterns, etc. Is there any way to fix this with an anti-aliasing program for Final Cut Pro X?

 

I'm going to obviously work around that and my question is, how do I make sure that when exporting to Blu Ray I don't get those issues of aliasing? Has anyone ever exported to Blu Ray from an FS700 and how bad is the aliasing? I'm a perfectionist when it comes to quality, etc and my film is a narrative feature and it's my first. I have used a Canon EOS 1D Mark IV prior and I know all about the horrors of aliasing and noise issues...a little too well.

 

 



#2 jcs

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Posted 02 February 2013 - 09:59 PM

Try adjusting the picture profiles to prevent aliasing on bright edges (I've seen this too): e.g. use the Cinegammas as well as turning detail to -7 (or experiment with the Detail settings).

http://provideocoali...hd_camcorder/P2

http://blog.abelcine...-from-abelcine/

 

Since aliasing is a form of high-frequency noise, perhaps try Neat Video to remove. A super-resolution program could remove this kind of aliasing- perhaps also check out the Dark Energy plugin for After Effects.

 

Here's a way to remove aliasing but will soften the final image: (blur if necessary) and downsample the image until aliasing is gone, then upsample using bicubic or better (such as Lanczos). A final sharpen can help.



#3 HurtinMinorKey

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Posted 02 February 2013 - 10:12 PM

Just bought an FS700. Extremely happy with it. I've been doing some test shoots. I've been noticing that on 120 fps ad 240fps or anything over 60fps, there is aliasing issues on over-exposed whites when let's say behind green leaves, tree branches, etc as well as on glasses, some patterns, etc. Is there any way to fix this with an anti-aliasing program for Final Cut Pro X?

 

I'm going to obviously work around that and my question is, how do I make sure that when exporting to Blu Ray I don't get those issues of aliasing? Has anyone ever exported to Blu Ray from an FS700 and how bad is the aliasing? I'm a perfectionist when it comes to quality, etc and my film is a narrative feature and it's my first. I have used a Canon EOS 1D Mark IV prior and I know all about the horrors of aliasing and noise issues...a little too well.

I think you can use an interlace..



#4 Scott Goldberg

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Posted 03 February 2013 - 02:54 AM

Try adjusting the picture profiles to prevent aliasing on bright edges (I've seen this too): e.g. use the Cinegammas as well as turning detail to -7 (or experiment with the Detail settings).

http://provideocoali...hd_camcorder/P2

http://blog.abelcine...-from-abelcine/

 

Since aliasing is a form of high-frequency noise, perhaps try Neat Video to remove. A super-resolution program could remove this kind of aliasing- perhaps also check out the Dark Energy plugin for After Effects.

 

Here's a way to remove aliasing but will soften the final image: (blur if necessary) and downsample the image until aliasing is gone, then upsample using bicubic or better (such as Lanczos). A final sharpen can help.

 

I've decided to not use any Picture Profiles and just to shoot the setting with no picture profile. 

 

Any ideas on where to take it from here?

 

The provideocoalition site didn't work by the way....broken link?



#5 jcs

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Posted 03 February 2013 - 04:28 AM

provideocoalition site is slow, but appears to be working.

 

Why not use/create a custom picture profile? Minimally worth experimenting to see what you can come up with after reading the manual and the provideocoalition page.



#6 see ya

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Posted 03 February 2013 - 06:49 AM

Can you post a short clip? Native camera source that shows the problem.

#7 Scott Goldberg

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Posted 03 February 2013 - 04:00 PM

   It's quite minor but I'm thinking that if you see it in the original footage, exported, footage, etc it's gonna be quite evident on an HD screen. The brim of the glasses, it aliases. I mean, at the very least, these test shoots are good because they help a filmmaker understand how to work around issues if need be. Not sure if the aliasing is fixable or if it's just how it is with extremely sharp lines, etc? Does Neat Video clean it up? Can someone try it with one of the two clips I've posted?

 

Shot it with a 14mm 2.8 Rokinon lens.

 

 I'm iffy and will think twice about doing slow motion if there's really scattered patterns in a moving shot that can alias.



#8 Scott Goldberg

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Posted 03 February 2013 - 04:17 PM

A more "severe" aliasing issue. Notice the main branch in focus outline. I understand my whites may be over-exposed behind but I didn't too much noise on the darks such as the greens and the browns. When I tried to color grade (not shown in this photo) it made it slightly worse and more noticeable. This setting is on NO Picture Profile setting.



#9 see ya

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Posted 03 February 2013 - 04:57 PM

Haven't had a look at the clips yet but one thing with the Sony cams is that they capture full luma upto 255 so if you aren't already make sure you pull your highlights down to 235 before making any judgements on blown highlights and aliasing, viewing full luma in any media player or NLE preview will show as solid white and could lead to wrong conclusions. Not saying its the reason just an added consideration.

Another example of this is the FS100 or 700 with the Speed Booster slow motion video EOSHD posted recently, the levels weren't pulled down to 235 and consequently everything in the highlights looks bad in Vimeo or anywhere else.

A small simple thing that will only exagerate the situation.

#10 jcs

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Posted 03 February 2013 - 06:37 PM

See the charts here: http://provideocoali..._the_nex-fs700/

The FS700 has more vertical than horizontal sampling resolution. More vertical resolution makes sense since this is a 422 capable camera (where 422 has twice the vertical color resolution vs. 420).

The FS700 was rated at 800 lines horizontal and 1000+ lines vertical using a trumpet chart. Horizontal TV lines looks to be around 1000 when using a chart with straight vertical lines.

See the charts at the same link above showing what happens to resolution, detail and aliasing when using slow motion: even at 120 & 240fps, there will be some aliasing.

 

The FS700 has a Detail setting in the picture profiles which you can change. It allows separate horizontal and vertical sharpening. You might try setting up one picture profile with Detail set to OFF, and another set to Default, and another set to turn sharpening off on horizontal detail only. Then shoot a few clips and compare.

 

Also try Cinegamma2, which is supposed to prevent superwhites (you'll select this as a gamma setting in a picture profile). Also note you can copy picture profiles, so can have the same one in multiple places (say 1-3), where you only change a setting or two for each when testing. See: http://www.xdcam-use...o-many-cameras/

http://www.xdcam-use...php?f=47&t=1069



#11 Leang

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Posted 03 February 2013 - 08:51 PM

Please try and expose properly for sky levels and use the ND's within your FS700.  whichever profile you choose please customize to the lowest level of sharpness.  lastly, if you could please do a test for the exact same shot in 120fps and 240fps.  I would like to see how the aliasing behaves.  Know that any highlight reflection hitting edges will increase aliasing.  this is why you have to expose properly and use your ND filters.  don't worry if your foreground or midground are underexposed.  the test is for aliasing.  not lighting.  in a professional environment you light foreground and mid for exterior...



#12 Scott Goldberg

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Posted 03 February 2013 - 09:55 PM

How do I change the level of sharpness let's say if I do not use a Picture Profile setting? Is there any way to with the camera itself or it only through Picture Profile settings?

I ask because I've been thinking about not using the PP settings but if I can somehow fix aliasing issues or minimize it, I'm willing to take the time to do test shoots and test them out on cloudy and sunny days and see which works best.

My main two issues is video noise and aliasing. I have my ISO at a constant 500 (the lowest it can be). I come from the DSLR world and love that the FS700 has some great natural noise, but I try to minimize it as much as I can whenever I shoot.

#13 Leang

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Posted 03 February 2013 - 10:06 PM

How do I change the level of sharpness let's say if I do not use a Picture Profile setting? Is there any way to?

 

don't be afraid to fool around with the menu setting of your cam, ironically this is one of the most non-conservative sites around for fooling with pro cams.  you're not going to damage your cam when fooling with factory options...  also get your hands wet, bruv, read the manual

 

''The FS700 has 6 built-in picture profiles, each of which can be modified in countless numbers of ways.''

 

http://swainhart.org...erators-manual/



#14 jcs

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Posted 03 February 2013 - 10:17 PM

Picture Profile 1 appears to be the same as "Off"- modify it first.

 

You can copy from other profiles, reset back to default (original setting for that slot), as well as save them all to removable flash and reload them flash.

 

For your glasses example- try a gaussian blur of 4 (horizontal only) and add film/noise grain. Can't completely remove, but after this quick test unless you look for it, aliasing is not distracting. Same should work for the tree example. Trying out picture profile settings should be helpful. Use the on-screen histogram to check live exposure. Peaking works great for checking focus (as does the focus zoom button on the handle ("expanded focus")).



#15 Scott Goldberg

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Posted 03 February 2013 - 10:55 PM

Here's an aliasing test video.... Notice on the glasses, some of the plaid shirt.

120 fps, 250 shutter

 



Used a 28mm 1.8 Canon lens. This was on the run, with a Glidecam Vest and Arm. Quick takes, my woman had to go home and it was cold but she was a good sport.



#16 jcs

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Posted 03 February 2013 - 11:25 PM

You can completely remove the aliasing in the glasses case by using a tracked effect over the glasses. In Premiere Pro that's a Track Matte Key. Once the area is tracked with a sufficient mask shape, you can apply a Gaussian blur of 14 (horizontal) and the aliasing will be gone. Add in some noise grain and the final result looks good.

 

Thus, testing with Detail turned off along with Cinegamma 2 would be a good start.



#17 jcs

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Posted 03 February 2013 - 11:43 PM

@Leang- 120 & 240fps should have the same aliasing behavior ( http://provideocoali..._the_nex-fs700/ ). The tree branch in the example has aliasing internally- not over exposed. This can be helped by adding grain and/or using Neat Video. The Edge aliasing in the glasses should be helped using Cinegamma 2 and turning off or down "Detail" (sharpening). 60fps should have no additional aliasing vs. 24fps. In some cases shooting at 60fps and using After Effects Pixel Motion interpolation or Twixtor to create 120, 240fps or more could work well.



#18 Scott Goldberg

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Posted 04 February 2013 - 04:00 AM

The camera is a great, sharp camera. Based on one of the links, with the sharpness wheel, it definitely degrades in quality a little bit. As far as the type of sharp cinematic image for a 24fps setting, I think that this camera is a great upgrade from DSLRs. I'm very impressed by it to be honest. You just have to be careful with aliasing, and like some of you have said, be cautious, maybe fix it up in post production or add Neat Video or blur it slightly, things like that... I just want to make sure I have the best settings I can have, to ensure that I don't re-shoot. I'm starting a feature later this month and I've had this camera for a few weeks, it's a great camera, I'm still learning things here and there and every day I'm doing test shoots.

 

So would you suggest on the PP1 I turn the sharpness all the way down to -7 I believe it goes down to? Will that degrade the quality significantly? 



#19 Scott Goldberg

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Posted 04 February 2013 - 05:43 AM

What would you suggest as a PP setting for "Broadcast Safe", little to no aliasing, still a sharp image and a non-bleeding of greens, reds, oranges and bright colors? 



#20 jcs

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Posted 04 February 2013 - 05:58 AM

I'm learning as I go- recently purchased the camera and Speed Booster. Shot a bit today with a custom profile with Detail set to -7 and sharpened in post (recorded internally as well as to a Nanoflash). With color correction and grain, I'm getting filmic looks with much more detail than my 5D3, especially wide shots. No deal breaker issues so far with the Speed Booster. See the links I posted, Alister Chapman posted a profile that might work for you. I'm testing and learning the settings to create exactly what I want from scratch.




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