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yommytacoe
08-08-2010, 12:01 PM
Hey,
Sorry if this is a repost, I did a quick search and didn't find anthing.

I'm shooting a short film on my 7D, and I've noticed in the dailies that there's some noise in the picture even at low ISO's (200-400). Is this normal? Is there a way to avoid it when shooting or reduce it in post?

I'm thinking it's probably because of the 18MP on the smaller APS-C sensor, but I'm surprised it would happen at such low ISO's. I don't have any footage online but to give you an idea, the noise I'd say is comparable to my XHA1 at +6 Gain or so.

Thanks!

Lammy
08-09-2010, 10:02 AM
Is it swimmy blocky noise? Yeah it seems normal to me especially on shadows and even coloured areas like walls or sky.

No way to get around it except over-expose or one of the intermediary ISOs (ie: 160, which is ISO 200 but digitally darkened). This means losing highlight detail though.

yommytacoe
08-09-2010, 04:03 PM
Is it swimmy blocky noise? Yeah it seems normal to me especially on shadows and even coloured areas like walls or sky.

No way to get around it except over-expose or one of the intermediary ISOs (ie: 160, which is ISO 200 but digitally darkened). This means losing highlight detail though.

Correct me if I'm wrong, but can't the 7D only go as low as ISO 200 in Video Mode?

Lammy
08-09-2010, 04:37 PM
It can go to go ISO 100 or 160, but you have to disable Highlight Tone Priority.

David G. Smith
08-09-2010, 06:44 PM
Noise is not just a function of the ISO, but of proper exposure. If you are exposing so that your highlights do not clip (which you should with a digital camera), and your shadows fall of the lower end of the dynamic range (The Toe of the characteristic curve of the sensor), then there will be noise in the shadows. This also happens with film, as even low speed stocks, if not exposed properly, can be grainy, especially in the shadows. I would suggest getting some fill light into your shadows to decrease the luminance range of the scene (or bring down you highlights). I am using a T2i, but it is my understanding that they are very similar. What I do when setting up a shot is set the exposure using the TTL metering, set to spot, with the camera set to stills-Manual setting. The center spot works with a 1 degree coverage area, so I check the luminance range of the shot by moving the center spot around the scene and checking the exposure change. First set your exposure to the scene focus (usually faces, ect). Then move the center spot to check the highlights and the shadows. Then you can adjust your lighting and your exposure to get the scene to within the dynamic range of the camera, and what look you are going for. When I am shooting fictional narrative, I set up a couple of very soft, almost shadowless light sources, that I can bring in for fill so that I can make sure I am exposing properly.

PerroneFord
08-09-2010, 06:50 PM
As an addendum to what David said, put the camera on the Daylight white balance, and light to 5500k - 6500k. Combined with what David said, your noise issues should all but disappear.

If you are lighting tungsten balanced, you'll never get rid of the noise.

David G. Smith
08-09-2010, 06:56 PM
As an addendum to what David said, put the camera on the Daylight white balance, and light to 5500k - 6500k. Combined with what David said, your noise issues should all but disappear.

If you are lighting tungsten balanced, you'll never get rid of the noise.

Yikes, I have not run into that yet.... of course, I have been lighting to daylight so far... What's up with that... I am planning a project where I was planing to light to tungsten, and maybe a little lower (a new aesthetic for me... I don't like warm fuzzy... but Director's choice)... I see a whole new sets of test in my near future!!! :huh:

PerroneFord
08-09-2010, 07:01 PM
If you have to make it warm and fuzzy, shoot neutral or other semi-flat profile and push it there in post. The gain up in the blue channel is kinda noisy.

David G. Smith
08-09-2010, 07:24 PM
If you have to make it warm and fuzzy, shoot neutral or other semi-flat profile and push it there in post. The gain up in the blue channel is kinda noisy.

Oh yeah, I know what you mean. Good looking out... Thanks. Let me ask you, say I balance to tungsten, plus 1/2 CTO, and light to straight tungsten, then balance it back in post, would that hold the blue channel gain down? Of course, I could balance to daylight plus 1/2 CTB, and light straight to daylight, and then balance it back in post ..... Whatta think? I will test that for sure.

PerroneFord
08-09-2010, 08:36 PM
I don't take my camera off daylight unless I am FORCED to. The closer you get to balancing to tungsten, the more gain you're going to need to add. Considering that tungsten light carries about 100% more red light than blue, to balance it, you're going to add 100% gain to the blue channel. That's a TON of noise.

Daylight is already presumably balanced, though I find unless it's overcast, it's still a bit too red. So I try to push daylight or daylight plus CTB if I can. Something close to 6500K. I am about to re-stock my CFL and 4ft tube supply with 6500K light this winter.

yommytacoe
08-10-2010, 09:21 PM
This is all great stuff you guys. It's always so tempting to try to get everything perfect in camera, especially when you have the lighting and the means to do so. I'll definitely have to do some tests with your suggestions.

David G. Smith
08-10-2010, 10:42 PM
This is all great stuff you guys. It's always so tempting to try to get everything perfect in camera, especially when you have the lighting and the means to do so. I'll definitely have to do some tests with your suggestions.

Oh yeah, test, test, test. PerroneFord has brought up some great points. He knows his sh*t. I got a lot of tests to do now. I love it. Ain't Cinematography fun?!!!!

Snapper123
08-13-2010, 02:47 PM
So you guys would recommend overexposing as a general rule? I personally don't like the noise I get in my blacks and shadows at ISO 100 when I expose right at the correct point...I don't wanna say that film doesn't do the same thing, but digital noise looks awful compared to film noise, it really gives me a nauceous, dizzy feeling when I look at it. When I overexpose by one stop and take another video of the same subject, the problem tends to completely go away, like a weight lifted off my eyes....despite the slight brightness, the overexposed footage just looks more 'comfortable' and 'cinematic' with the absence the noise, plus it doesn't make my stomach churn.

But I have no experience in techniques to get rid of noise in post, that is probably something I'd leave up to the editor after I shoot my own footage, so I have no clue how I should probably be shooting my stuff in a way that works BEST for the editor and for the aesthetic, I'm only going by what I see when I slap the videos onto my computer for quick test checks. Noise is my biggest priority, but it's not like I really want to have super bright highlights or very grey blacks either, which seems to be the downfall to this work around. I'm really unsure what to do, but I know that that digital noise is a pest to me, it makes me feel plain dizzy in the stomach, and that's why I try to devote my money toward prime lenses and making sure I have adequate light. But no matter what, there's always going to be a dark spot in the video that just can't be covered by light...and so far, overexposing + flat styles tends to be the only way I've seen hands on that gets totally rid of the noise in those 'always will be there no matter what' dark spots or colors.

It's not just really blacks, when I expose the shot like the camera says, it just tends to have a whole mask of noise, in the blues, reds, browns, dark greens. Even if the blurred background is even slightly dark, noise is everywhere, it looks like a 'mask' to the point that you'd think it was something wrong with the glass. I don't feel like I'm getting normal footage at ISO 100. The things I probably need to dip my toes in, though, are; white cards, grey cards, using the brightness histogram, ect ect. But as reluctant as I am to send my camera in for a check, I may just have to send it in, I've always felt the noise levels with my camera are a good 4X higher than the footage I've seen from users who have the camera set on auto, for crying out loud. It's almost like my ISO level is 'constant' through 100-800, but that simply the brightness/darkness effects the visibility of the noise, rather than the ratio of noise being lower to higher from 100 to 800.

Razz16mm
08-13-2010, 03:01 PM
Silicon sensors are all daylight sensitive devices with native color temp in the 5000K range for equal exposure of the RGB channels.
Under uncorrected 3200K tungsten light there is effectively a 2-1/2 stop difference between the red and blue channel exposure levels compared to 5000K. This is a property of the light and you effectively lose 2-1/2 stops of DR under tungsten regardless of how you adjust white balance of the camera.
The only thing that works is to filter the light or the lens to correct closer to daylight balance before exposure, but you then trade off overall sensitivity or available light levels to get a more balanced exposure.

David G. Smith
08-13-2010, 03:02 PM
No. The recommendation is not overexposure, but correct exposure. Making sure that there is enough light in the shadows so that they are exposed properly. Over exposing the highlights will make them clip. Now lighting to a flatter image and adding contrast latter is also an approach that some folks use, but with the vidoe DSLRs, exposure and contrast are something that I want as close to what I want in the original image.

David G. Smith
08-13-2010, 04:50 PM
Now the issue with the noise being constant between ISO 100 to 800 may be an issue with your camera. It might be a good idea to have it checked at a service center.

yommytacoe
08-14-2010, 12:20 AM
I followed lots of the advice in this thead today on set, lighting the shadows a bit more, turning off highlight tone priority, and whitebalancing to daylight. Everything turned out much much cleaner. I was shooting on a 50mm 1.4, and a tokina 11-17 2.8, and everything looked much much cleaner, even as high as 400 ISO. Thanks for all the tips guys!

PerroneFord
08-14-2010, 02:29 AM
Glad that worked out for you man. It does make a HUGE difference. Film has a similar issue in that the blue part of the emulsion is generally less sensitive than the red or green. Thus shooting with daylight balanced HMI lights is popular with them too.

Snapper123
08-17-2010, 03:40 PM
Hey guys, I just did a test where I filmed a close up of garments from a pile of laundry that was sitting on a dinner table right in front of sunshine windows.

For the test, I shot 8 videos, all at ISO 100, Daylight White Balance, and Standard picture mode. The variation was that I opened the aperture/lowered the shutter for each video to overexpose it 1/3th step at a time. The first four videos do this process from correct exposure, all the way to +1 exposure, with Light Compensation off, and the next four videos were of the same thing, with LC on Strong.

Here's an example of one of the videos of the test:
http://www.youtube.com/watch?v=hffb9430p2s

(Youtube applied a pretty extreme contrast mask for some reason, the video is much lighter and noise-appearant in the native video...but this is just to show the subject of what I filmed. I guess this Youtube mask at least proves that the noise is maskable by editing the contrast, but that would mean I'd need to shoot a bit flatter or something naturally? Yet some people advise against that...I just don't know what to do!)

Basically, the results that I personally noticed were that I enjoyed the +1/3ths non-LC and +1/6th non-LC video the best out of the group. The +1 seemed slightly too overexposed + tons of noise, and the correct exposure video seemed to have too much noise in the darkest/most blurred area (the bottom left corner). They all had noise in that specific blurred/dark corner though, even beyond dark areas, the 'blurred' areas have been giving me the most trouble since day one...even if the color of the blur is not that dark! I didn't enjoy anything from the LC videos, too much noise, but I didn't realize I changed the focus just a bit so that could have threw it off - I doubt it.

Any help on what I could be doing differently (beyond poking 14 lights onto the laundry?) From my tests, I have the mindset that absolutely any footage from the T2i needs at least a tad of contrast editing to mask the noise, but what would be the perfect ideal way to film your subjects with that "I'm going to have to add a tad of contrast in post." idea in mind? Would it be a flat, slightly overexposed style? Or just flat with exact exposure? Just what - for the perfect result?

I mean, just my own tests by now, I've pretty much discovered that straight from the camera, +1/6th is the way to go, if shooting on Standard. It even ADDED a good, very slight highlight to a area that was otherwise noisy on perfect exposure. And just with another test too testing picture styles, I almost feel that Standard has the least noise of all, too, but it's very hard to tell. But overall, it's so hard to go by my own tests because I really don't know how situational all this is.

Also, here is a random video, but can anyone tell me if they see 'checkering' in the blurred area (right side of screen?) To me, it looks like what happens when you watch a Native HD video on Youtube, but when you watch it in 360P (it turns blocky). It's not that extreme here, but it is there on my computer, and there's no reason it should be happening on a native file. It's on ISO 200, has nothing to do with noise, just look for something that looks like solid blockage all through the blur:

http://www.mediafire.com/?w3bq6u5rierpcgi

Please judge only when watching it at 1080P and on a 1080P monitor, that's where it seems to show up!

PerroneFord
08-17-2010, 06:03 PM
For the test, I shot 8 videos, all at ISO 100, Daylight White Balance, and Standard picture mode.


Well, there's major mistake one. Get off standard mode.



(Youtube applied a pretty extreme contrast mask for some reason, the video is much lighter and noise-appearant in the native video...but this is just to show the subject of what I filmed. I guess this Youtube mask at least proves that the noise is maskable by editing the contrast, but that would mean I'd need to shoot a bit flatter or something naturally? Yet some people advise against that...I just don't know what to do!)


There is nothing wrong with shooting a bit flat. HOW flat to go is the question. The camera comes with a fairly nice flat profile called "Neutral". I highly recommend you start shooting there. And perhaps now, you will understand why experienced shooters continue to tell newer shooter that you CANNOT get great images out of these cameras without some tweaks in post, or some VERY carefully crafted images. These are not point-and-shoot cameras if you want professional results. You have to do some work.



Any help on what I could be doing differently (beyond poking 14 lights onto the laundry?)


Yes, poke 8 lights onto the laundry. I've said it 1000 times. These cameras LOVE light. The more you give them, the more they love it. Indoors, in the dark, they suck, just like any other video camea, or film for that matter. You know that phrase "Lights, Camera, Action?" There's a reason lights comes first.



From my tests, I have the mindset that absolutely any footage from the T2i needs at least a tad of contrast editing to mask the noise, but what would be the perfect ideal way to film your subjects with that "I'm going to have to add a tad of contrast in post." idea in mind?


There is no perfect, ideal way to mask the noise. The best way to do that is to reduce contrast when shooting (hence why we say shoot flat), and increase contrast in post. Those who don't want to do the work in post end up with images that just aren't as good. You cannot have it both ways.




Would it be a flat, slightly overexposed style? Or just flat with exact exposure? Just what - for the perfect result?


A flat, properly exposed, or even slightly underexposed frame is best.



I mean, just my own tests by now, I've pretty much discovered that straight from the camera, +1/6th is the way to go, if shooting on Standard.


Ok, but don't shoot on standard.



It even ADDED a good, very slight highlight to a area that was otherwise noisy on perfect exposure. And just with another test too testing picture styles, I almost feel that Standard has the least noise of all, too, but it's very hard to tell. But overall, it's so hard to go by my own tests because I really don't know how situational all this is.


You are in the midst of a very long, and very steep learning curve. After about a year of this, you'll be making some nice images. But you're in calculus class right now without having taken algebra, or trig. Your fundamental knowledge of exposing a camera is weak and it's biting you in the butt. Same scenario a great many people new to these cameras are in. So don't be discouraged. Just understand there's a lot to learn still.




Also, here is a random video, but can anyone tell me if they see 'checkering' in the blurred area (right side of screen?)

That "checkering" you see is the codec running out of bandwidth. These cameras shoot 35-50Mbps approximately. To adequately do the job we're asking them to do, they need about 3 times that much. They don't have it. So when we give them difficult scenes to deal with, they allocate more bandwidth to sharp, in focus areas, and much less to dark, and blurry areas. This is absolutely normal and expected. Those areas get blocky. That's how the codec works in these cameras and a great many others.

In order to minimize this behavior, you've got the make the job easier for the camera. And that means that your dark areas can't be quite so dark. And if you are going to leave parts of the frame out of focus be aware how dark you let them get when shooting.

MANY of the problems in these cameras is solved by using a decent profile. I use the Marvel Cine profile, and feel it is the best one out there for people who are doing post. The "Neutral" in camera is a good place to start though.

Jordan Scott Price
08-17-2010, 06:16 PM
I use the Marvel Cine profile, and feel it is the best one out there for people who are doing post.

I use this too for all of my narrative work.

Download Link (http://http://www.martinbeek.net/canon7d/Marvels_Cine_Gamma_7D.zip)

Marvel Website (http://marvelsfilm.wordpress.com/2009/10/19/canon-7d-picture-style-with-cine-gamma-s-curve-free-download/)

Lammy
08-24-2010, 05:46 AM
They all had noise in that specific blurred/dark corner though, even beyond dark areas, the 'blurred' areas have been giving me the most trouble since day one...even if the color of the blur is not that dark!


Yup, that's just the look these DSLRs have. Anyone else telling you otherwise is blind or happy about it.

Even in the best DSLR shot videos, in the best music videos by Joseph Kahn, In Philip Bloom's videos, in Shane Hurlburt's videos, in TV shows like House or True Blood or Numb3rs... it's there.

That swimmy, processed, blotchy dancing noise. It's very different to film or a professional camcorder grain. It just wont stay still, and using a picture profile like neutral and a program like Neatvideo wont eliminate it.

I don't know if it's the compression (although Nikon's video doesn't exhibit it as bad), or if its the debayer or processing algorithms.

We'll just have to live with it as the flaw of this kind of system :violin:

JustinBrown
10-01-2010, 08:20 PM
Bump!

I have been reading about this a little lately. Something I have been wondering, now that I am literally inches from purchasing either the 7D or 5dMKII, is whether the sensor size matters as much as the exposure. In some noise comparisons between the two it is obvious that noise is present in both. My question is, is it really that noticable? I mean, to the untrained eye? Would I be better spending a little extra to get the larger sensor? Or is it as I suspect, and really I just need to plan around my lighting situations when shooting?

I would really be happy with either one, but they both cost a dime or too and I would feel silly for selling my self short due to my own ignorance of the technical aspects.

Thanks!

PerroneFord
10-02-2010, 03:16 AM
In a controlled scenario, it would take a LOT of effort, even by someone trained, to tell the difference. But as conditions move away from the ideal, the larger sensor will have more of an advantage in noise simply because it can gather in more light.

If you are controlling the lighting when you shoot, the 7D (and T2i) offer some significant advantages, not the least of which is 720/60p which allows you to shoot overcranked for certain things. The improved screen on the T2i is also a very welcome addition.