F3: Noise in Slog?

Barons said:
Baselight Avid Windows has Truelight, a LUTish option that contains many LUTs and colorspaces, and allows you to import your own if they're not there already. You can start grading with a Truelight look or not - whatever works for you. I find it quicker to work without Truelight although I do edit with the auto AVID LUTs on, and then remove them before grading.
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its more about how the controls on your surface are mapped, working with LOG images on a surface mapped for responce on LIN images means tons of twirling in the shadows & highlights plus unworkable hairtrigger control of the mids.... makes for a very long day.....

How that bounces back into this discussion is using LOG images in a system mapped for LIN responce is frustrating, so the option of applying a LOG->LIN lut first and then gradeing in LIN as the software is designed to do means that it is possiable to clip & crush data if the base exposure does not match the expected input values of the lut in question

And this might push noisy shadows into the lower mids where noise is much more obvious

I graded a comedy / thriller shot on F3, and it was really REALLY clean... lowest noise i had seen to that time (yea, now the F55 trumps it), but for two years ago it was amazing, and still amazing

Excessive noise in F3 would seem to be more a case exposure off, or LUT's applied in a way that maps shadows into the loweer mids... that camera is super clean when handeled with care

d
 
Barons said:
Back to the original topic... here is a great article by Alister Chapman: http://www.xdcam-user.com/alisters-blog/
I highly recommend also going to the link he has embedded about exposing for hypergammas.
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I think it is already quite common knowledge of the mapped reflectance values to slog on the F3, F5/F55. Regarding the article do note that on the F3 using cinegamma 3 that your image will actually appear BRIGHTER than it really is compared to all the other cinegammas including slog where images actually appear darker. (CG3 places middle grey up around 60-65%)

I'd say the real problem is the fact that Sony has failed to exploit adequate monitoring LUT's on their CineAlta cameras soon enough. On the F3 it was only available through the initial $3200 RGB/SLOG upgrade, and on the F5/F55 we have been waiting since March. Not very good for a "professional cinema" camera.

I can say from reading conversations between Alister and professional DP's who actually work on HBO, Showtime, and other network shows there is a huge difference in view and opinion when it comes to what is "proper exposure" on a camera. Alister's approach seems to be much more scientific and based on charts whereas in the realities of the "trenches" a stop or two really won't matter when you have several ton grip trucks at your disposal and you're not shooting a 16 stop scene anyway. (I steal those words from a DP who actually said that).

For now, and until I really get more experience to grad out my slog images better I will stick with the more scientific route of exposure so that in post I am not faced with too many variables to deal with and can hone my craft a bit more before stepping out into more uncharted territory.

I do agree that for many slog does seem to have been a complicated subject to conquer.



Dermot said:
its more about how the controls on your surface are mapped, working with LOG images on a surface mapped for responce on LIN images means tons of twirling in the shadows & highlights plus unworkable hairtrigger control of the mids.... makes for a very long day.....

How that bounces back into this discussion is using LOG images in a system mapped for LIN responce is frustrating, so the option of applying a LOG->LIN lut first and then gradeing in LIN as the software is designed to do means that it is possiable to clip & crush data if the base exposure does not match the expected input values of the lut in question

And this might push noisy shadows into the lower mids where noise is much more obvious

I graded a comedy / thriller shot on F3, and it was really REALLY clean... lowest noise i had seen to that time (yea, now the F55 trumps it), but for two years ago it was amazing, and still amazing

Excessive noise in F3 would seem to be more a case exposure off, or LUT's applied in a way that maps shadows into the loweer mids... that camera is super clean when handeled with care
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This is exactly what I'm going to try next. I want to use an IDT LUT to convert the slog to ACES linear, then grade in linear land where there is more range available and I can REALLY tame out those bad-ass highlights!


Don't think there can be a difference? Check out this video:

http://vimeo.com/64900919
 
yea i saw that elsewhere... can't really say much without haveing access to the camera orignal, but the loss of detail in the highlights is puzzleing, but i have zero experience with anything other than Slog or Slog2, so no idea what the 709 & 709/800 does in the real world... this shot may be just fine with an exposure adjustment before an Slog LUT... just can't say with what is presented
 
I'm not that familiar with the F55 , but the first 2 LUT's you're using look like the internal LUT's that Sony put in the F3. If so they are pretty much garbage for recording slog. They will cut off most of your highlights and are only intended to give you a better idea of your basic exposure for midtones while shooting. If you record them you might as well shoot 709. I don't know how you are using them or if they are even available for color post. Not a proper LUT for grading though.
 
I'm not sure why Sony put in a LUT that seems to do nothing other than remove the nice range of slog. If you incorporate the LUT you record it that way - a really bad idea. The LUT needs to be used in the monitoring stage where it would be very useful.
Re: Alister - he gives good information on how to get the most out of slog, but obviously whatever works works. Having a monitor with you that delogs the image is the only way to be really sure you're getting what you want (and a waveform monitor).
 
Supposedly the 7Q will be able to create a good monitoring LUT but I'll beleive it when I see it. So far RED has Sony beat by a mile in this regard.
 
Red shows linear does it not? Seemed perfectly intuitive to me only bummer being that the histo is tied to the non existant iso control
 
The good news for the F5/F55, is this month's firmware release will add monitoring LUTs in-camera so while you are shooting in SLOG everything will appear at normal levels in the viewfinder, monitor, etc.. so no need to worry about managing monitoring LUTs externally.


Morgan - as for the F3, if you buy the RGB/SLOG upgrade (you can get is used pretty cheap now) you will gain the ability to build your own monitoring LUT and which you can load into the F3 and at least work with slog on your monitors with "correct" levels. The LUTs you can build are limited to 1D LUT's only, which means at most you can control separate R G B channel values, but not hue, saturation, etc.. but I still think this has tremendous value.

EDIT: Just realized that even without the paid upgrade (info), as of firmware v1.2 on the F3 you get EI mode which would also help you boost your image output for monitoring while underneath you are recording unadultered slog.

Andy from Abelcine as always explains it best: http://blog.abelcine.com/2011/12/29/s-log-and-the-sony-f3-part-2-exposure-index-mode/
 
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I'm having zero problems with noise in S-log, but I'm having serious trouble with moire and aliasing, which I've never seen on the camera before. Yes I'm shooting 8 bit, but that has nothing to do with the sensor. Any ideas? I have read, turn detail off, not sure about this though. I thought it might be the lights I'm using, but it can't be that, can it?
 
JackCarter said:
I'm having zero problems with noise in S-log, but I'm having serious trouble with moire and aliasing, which I've never seen on the camera before. Yes I'm shooting 8 bit, but that has nothing to do with the sensor. Any ideas? I have read, turn detail off, not sure about this though. I thought it might be the lights I'm using, but it can't be that, can it?
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Shooting 8 bit does have something to do it, compromises do have to come from somewhere. I definitely saw aliasing issues from the internal codec for instance.
 
yoclay said:
Shooting 8 bit does have something to do it, compromises do have to come from somewhere. I definitely saw aliasing issues from the internal codec for instance.
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I hope your right, are you having any issues from 10 bit recording S-log? I've never had issues of moire and aliasing from non S-log recording in 8 bit. I thought moire and aliasing were sensor issues, not codec?
 
starcentral said:
Jack, what is the nature of the scene you are shooting exactly? And on what do you see the artifacts?
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Hi Dennis, I've seen it in various shots recently, when using s-log. For example, on Saturday I was filming a pan, off a door on to a wall which had a mirror. That wall has striped wall paper, and when the camera stopped panning, all those jagged lines appeared, I didn't notice it until I got it in to the computer.

On another shoot I was doing this long dolly shot, the camera slowly pulls back. On the side wall was a window, and this line twittering appeared along the black line of the window frame and the glass, and in the same shot, a loads of lines appeared on the microwave door, like in the old days on TV, when a TV presenter wore a striped suit jacket, all these lines would appear.

It looks like the 5d Mkii footage I've seen, but I've never seen this on my camera before, and I've had it nearly 3 years. Only thing that is new on this shoot is I'm using S-log, and some 5500k lighting. It has to be sensor related, not codec, am I right?

Thanks.
 
I would do an all reset on that camera and if the issue still persists take it into Sony for service. Sounds fishy, really you shouldn't get a lot or ton of aliasing/moire on it.

Regarding slog and night scenes, I agree. For darker scenes I would actually use cinegamma 3 because it lifts the mid-tones to 60% which is nice to work with in post.
 
starcentral said:
I would do an all reset on that camera and if the issue still persists take it into Sony for service. Sounds fishy, really you shouldn't get a lot or ton of aliasing/moire on it.
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Thanks Dennis. Perhaps I made it sound worse than what it is, I hope. I'll send you a link to the finished project, by the end of the month, if you don't mind watching it. If you think it needs sending in after watching, then so be it. If I reset the camera, won't I have to re-install all the firmware and S-log again?
 
Sure send a link. I'm no expert, but I shot with the F3 for almost 2 years and never once saw anything that would bother me (unless zooming in 200-300% on the NLE and really looking).

You mentioned it just seemed to start? That was the odd part.

You won't have to reinstall any firmware after doing a reset. A reset just puts all your menu item settings back to defaults, and you will lose all custom picture profiles. I don't know if the RGB/SLOG is wiped out in a reset, but you can remove the upgrade and put it to any SXS card just to be SAFE. :thumbsup:
 
I'm wondering why are you suggesting a complete reset which is a PITA. AFAIK the only things that could affect this are detail, aperture and frequency. Just look at those settings & just do some tests. Best thing I know of for looking at moire is to focus on a laptop screen, especially zoomed in . You'll get plenty of moire, then just change your settings including Slog and see if you can get rid of it or what makes it worse. If you have a good monitor you should be able to tell what's going on in a hour.
 
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