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com21

Sony A7s NOISE problems, anybody experiencing?

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Sorry if this was posted before. I been using the A7s a lot lately and I saw all the AMAZING low light tests, but yet I am did not have the same results...ever. We just shot a short Film on the Sony A7s, using Rokinon Lenses.Using their SLOG-2. We were at native ISO of 3200 ( the lowest you can go in Slog) f4 on a Rokinon 35mm. The problem is a lot of the shots have a really good amount of grain to them. We shot a previous movie on this camera were we had Night Scenes in a Park and we were getting crazy amount of grain at night with SLOG-2, that we just decided to shoot without it, and it turned out great. Now This Short Film was a more of a controlled situation, so we decided to use the Slog2 profile, but ended up with grainy footage at its lowest iso, and I know you are supposed to compensate by us EV+1,or,2 or even -,1or2 for grain, we tested every which way and still got grain. I keep seeing crazy tests of people going 10,12,16 thousand in SLOG-2 and having it be crisp, I know it looks milky still obviously, but still crisp when graded. Yet we are never able to achieve this in low lit scenes in SLOG-2. The only reason we chose this over the 5D for the dynamic range and more manipulation in post you get with SLOG-2, but the 5D could have done this non grainy easily. My question to anybody who OWNS/or Used this camera  in SLOG-2 specifically, at Night or Interior DARK scenes, has anybody got similar results or not. I did tons of research, videos, posts I just need to know its me and not the camera, or any suggestions period. Without the LOG, i shot outside on my street/downtown in the city at 35 thousand ISO and gotten clear good images, but with Slog-2 at its Lowest ISO it seems like we need to over-light the scene in order for it to not be grainy. I took some snapshots in Premier, the first one is with SLOG still on, the Second is with a Lut, just for reference. I just want to know if I am doing anything wrong, or forgetting to do anything, or whatever. ALSO, quick NOTE: this camera had a damaged senor before, but the owner got it fixed by Sony. I hope thats not the problem, but I am here to find out what is.  Any info would help, thanks. Alex.s.

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EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

Yeah the problem is using slog2 in low light. Slog2 on the a7s is noisy in general, but especially in low light. Go with one of the other picture profiles. And when shooting slog2 in regular situations, overexpose 1-2 stops. 

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thanks for reply, but wouldn't it also be grainy in regular mode then if the reason is their dual stage iso, I had good experiences in low light situations without SLOG2, but with it only bad ones on yet, which is why we didn't use it on our previous short, that had less light, but turned out great anyways. this had more light coming in, but in SLOG and looks like turds, but yeah I see your point about overexposing, maybe its just me, I dunno might have had my expectations to high with this cameras capabilities.

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the picture in the first post is very very under exposed, all log profiles have noisy shadows especially if you are at iso 3200+. i recommend you to shoot +1 even when in low ight situations

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Well, you have to learn how to expose a camera. That scene is underexposed. Slog moves the shadows into the midtone zone, this makes you believe you are exposing correctly, but it's actually wrong. Shadows are noisy, your image is 100% shadows, 100% noisy. Upping ISO makes shadows less noisy = your image less noisy.

Use a lightmeter, or a screen with a lut.

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12 minutes ago, Nikkor said:

Well, you have to learn how to expose a camera. That scene is underexposed. Slog moves the shadows into the midtone zone, this makes you believe you are exposing correctly, but it's actually wrong. Shadows are noisy, your image is 100% shadows, 100% noisy. Upping ISO makes shadows less noisy = your image less noisy.

Use a lightmeter, or a screen with a lut.

Wait so you would recommend increasing the ISO to get rid of the grain?  because when we did that in tests it just made it way worse, we also did have a monitor, but no lut input option on it.


Also, in case it wasn't obvious we were shooting a Film Noir short.

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Film Noir doesn't mean no lighting. It would be better to overlight the scene and underexpose the camera than underlight the scene and overexpose the camera. The latter will always give you more grain. 

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Well that's what should happen, I don't have a A7s, but when you are shooting log you can't judge exposure easily on screen.

Just get a lightmeter, and meter that thing correctly. You can increse the iso, or increase the light, just don't underexpose.

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1 minute ago, Inazuma said:

Film Noir doesn't mean no lighting. It would be better to overlight the scene and underexpose the camera than underlight the scene and overexpose the camera. The latter will always give you more grain. 

I was just saying it was Film Nior, I know it doesn't mean that.

Just now, Nikkor said:

Well that's what should happen, I don't have a A7s, but when you are shooting log you can't judge exposure easily on screen.

Just get a lightmeter, and meter that thing correctly.

I will for sure need to do that, but as far as A7s go, more iso in Slog-2 means a shit tons more grain, in our tests. Day and Night.

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16 minutes ago, com21 said:

I was just saying it was Film Nior, I know it doesn't mean that.

I will for sure need to do that, but as far as A7s go, more iso in Slog-2 means a shit tons more grain, in our tests. Day and Night.

Well, I think what's happening is (I might be wrong, but it has happend to me with very flat profiles) that you want a dark look, so you expose in camera to make it look dark, but since you are shooting in slog you are getting fooled, because slog brings the shadows up and makes things look correctly exposed on the small screen. Once you get to your computer you notice it looks horrible.

So what you must do, is to expose correctly, the image has to look bright on the screen , it will look bad, but log doesn't look good. Afterwards, you will delog your footage, this will make the noisy areas go back into the dark where you don't see the noise.

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You might be correct. but I wasn't looking at the monitor as fail-safe to see if its exposed or not, we knew we had a chance to get grain because we did previous tests before, but in those previous tests it was way darker outdoors type of shots, and as dark or maybe even misleadingly dark these jpegs looks, but the room was lit, or so it seemed i guess.



Here are some more Jpegs to so some other shots, not every shot turned out grainy, and these on this post are the worst of it. I just wanted to see if anybody else had this experience with Slog-2 and the A7s specifically.. I appreciate all the replies though.


I get it though, I need a fucking light meter.

Thanks

Alex.s.
 

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So what are you basing your exposure on?

 

Anyway, I'm shure someone with an A7s will come by and say something like, haha 8bit, slog2, lots of shadows = no fun.

Did you record this internally or do you have a 4K recorder?

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I was basing the exposure on previous test at that same exposure but less lighting actually, and I was also eyeballin it. . I know , I know. I know. Which never failed me.  Till now. ...The thing that upsets me the most is I can keep the setting on camera the same as far as Iso. Shutter. And keep the same f-stop. And the exactly the same lighting. But just turn off slog2 and it won't be grainy at all.  But I guess if it does what you say it does to the shadows, then it makes sense.  Also Nah didn't have an external recorder. I wish, but not $$.    Yeah I'm sure someone will say the slog-2 thing and 8-bit.  I reAlly like this camera. I got nice images from it on previous projects in good light and low light in slog s-gamut and cine and rec709. Just not this time.   

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2 hours ago, com21 said:

I was basing the exposure on previous test at that same exposure but less lighting actually, and I was also eyeballin it. . I know , I know. I know. Which never failed me.  Till now. ...The thing that upsets me the most is I can keep the setting on camera the same as far as Iso. Shutter. And keep the same f-stop. And the exactly the same lighting. But just turn off slog2 and it won't be grainy at all.  But I guess if it does what you say it does to the shadows, then it makes sense.  Also Nah didn't have an external recorder. I wish, but not $$.    Yeah I'm sure someone will say the slog-2 thing and 8-bit.  I reAlly like this camera. I got nice images from it on previous projects in good light and low light in slog s-gamut and cine and rec709. Just not this time.   

A little thing i've used when exposing dslrs with very flat picture profiles is to try expose the scene first with the slog then switch to the standard picture style just to see the exposure then go back and change the settings and repeat till you got something good, you will often notice that you are underexposing very much because in slog everything is in the midtones.

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@com21 Let me let you in on a little secret........ Any and I mean ANY video camera,film camera, photo camera ANY will show noise if underexposed.

Realistically you could have EASILY shot all of those scenes at iso 12800 - 25600and have had a PERFECTLY CLEAN image. 3200 iso being the basis you severely underexposed your image on an amazingly powerful low light monster camera. Shoot that same scene around 12800-25600 and prepared to be AMAZED. Also I still recommend shooting in SLOG  in dark scenes when raising the is so much as the highlights will blowout if you do not shoot in SLOG and raise the iso so high.

 

 

 

 

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1 hour ago, j.f.r. said:

@com21 Let me let you in on a little secret........ Any and I mean ANY video camera,film camera, photo camera ANY will show noise if underexposed.

Realistically you could have EASILY shot all of those scenes at iso 12800 - 25600and have had a PERFECTLY CLEAN image. 3200 iso being the basis you severely underexposed your image on an amazingly powerful low light monster camera. Shoot that same scene around 12800-25600 and prepared to be AMAZED. Also I still recommend shooting in SLOG  in dark scenes when raising the is so much as the highlights will blowout if you do not shoot in SLOG and raise the iso so high.

That's what I discovered straight out of the box - it was the first thing I tried, straight into that range trying the different profiles whilst overexposing. The reason for that was because I had read another thread on the same subject (might have been on this forum) where people assumed they had a bad copy because of all the blocky mushiness and hordes of mosquitos plaguing their images.

I found that Cine 2/4 is better for night time, just as Philip Bloom advised in his seminar. S-Log is more for highlights.

 

 

 

 

 

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Another option is to get something like an Atomos for the waveforms. Expose skin tones at around 60/70 IRE with a grey card (about 2 stops over). Also, create your own LUTS which have a minus two exposure compensation in them as well as the desired look on - I use Arri log to rec709 as a great starting point - and load 'em on the Atomos. This will give you a great starting point on exposing and hiding all that noise. When it comes to post, crush the blacks in post to get rid of shadow noise. I shot these at 125000 ISO or thereabouts...

ALLRUSHES.01_36_24_06.Still025.png

ALLRUSHES.01_44_48_24.Still026.png

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