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Sony HVR-Z7 / HVR-S270
Handheld and shoulder mount versions of this Sony 3-CMOS HDV camcorder.


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Old April 26th, 2008, 10:52 AM   #1
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Noise - Gain & Detail

I got my Z7 a couple of days ago. Thankfully there is no sign of the focus issue which seems to have affected some of the cameras. In general it seems a well thought out camera, but I am concerned that I find the image surprisingly noisy at 0dB. If I reduce the gain to -6dB the noise reaches what I would consider an acceptable level, and I find I can improve the noise in the image further if I reduce detail to around -4. Does anyone else find the image noisy at 0dB? I'm viewing the image on a 32" lcd for testing. I don't really want to have to use -6dB by default as it loses me a couple of stops, and part of my reason for getting the Z7 was it's improved low light capability. Are there any other adjustments I'm missing which I can use to reduce noise while keeping gain at 0dB?
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Old April 26th, 2008, 12:27 PM   #2
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I got my Z7 a couple of days ago. Thankfully there is no sign of the focus issue which seems to have affected some of the cameras. In general it seems a well thought out camera, but I am concerned that I find the image surprisingly noisy at 0dB. If I reduce the gain to -6dB the noise reaches what I would consider an acceptable level, and I find I can improve the noise in the image further if I reduce detail to around -4. Does anyone else find the image noisy at 0dB? I'm viewing the image on a 32" lcd for testing. I don't really want to have to use -6dB by default as it loses me a couple of stops, and part of my reason for getting the Z7 was it's improved low light capability. Are there any other adjustments I'm missing which I can use to reduce noise while keeping gain at 0dB?

Mike I just shot an event a couple days ago. Pretty low light in the place. My footage was also pretty noisy. Unfortunately I decided to leave it in auto mode, so I really can't say what the gain was, but I am suspecting it was on 9. I sure did not think there would be any noise with 0 gain though. Keep in mind if you are in the manual mode you have to make sure you are controlling not only gain, but iris and shutter speed as well manually or the camera will do it in auto to compensate for the manual settings you are using.

Bruce
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Old April 26th, 2008, 01:26 PM   #3
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yes - all fully manual.

I've attached 2 enlarged images of the noise for comparison, the first at 0dB F4.4, the second at -6dB F2.8. The chart is on a plain white wall.
Attached Thumbnails
Noise - Gain & Detail-0db.jpg   Noise - Gain & Detail-6db.jpg  

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Old April 26th, 2008, 01:37 PM   #4
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yes - all fully manual.

I've attached 2 enlarged images of the noise for comparison, the first at 0dB F4.4, the second at -6dB F2.8. The chart is on a plain white wall.
That certainly does seem like a lot of noise. I have not seen this with my camera, just the other night when the lights were really low.

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Old April 27th, 2008, 08:10 PM   #5
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Your observations is EXACTLY my observations. The Z7 at -6db is similar to my older Canon A1 at 0db.

To say it shocked me is an understatement. It is obvious the way in which Sony got the camera to appear better in low light was to up the gain or voltage on the chip starting at a higher setting then others. The new noise reduction ability they have gave them a little room to move and from that they bumped up the gain starting point.

When I viewed the image at -6db I would consider it slightly worst then acceptable. At 0db, not acceptable at all. It ramped up slower then other cameras so at 9db it was better then the A1(A1 has no 9db setting anyway), but not in the shadows. Only in the brighter areas. In the shadows it was a muddy grainy dingy mess.

Very sad really,

Paul
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Old April 27th, 2008, 08:29 PM   #6
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Your observations is EXACTLY my observations. The Z7 at -6db is similar to my older Canon A1 at 0db.

To say it shocked me is an understatement. It is obvious the way in which Sony got the camera to appear better in low light was to up the gain or voltage on the chip starting at a higher setting then others. The new noise reduction ability they have gave them a little room to move and from that they bumped up the gain starting point.

When I viewed the image at -6db I would consider it slightly worst then acceptable. At 0db, not acceptable at all. It ramped up slower then other cameras so at 9db it was better then the A1(A1 has no 9db setting anyway), but not in the shadows. Only in the brighter areas. In the shadows it was a muddy grainy dingy mess.

Very sad really,

Paul
Paul how much light is in the room you are using these settings? Just curious.

Bruce
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Old April 28th, 2008, 10:15 AM   #7
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The same thought crossed my mind - that Sony had simply renamed '0dB' as '-6dB' - would they really do something so cynical (and stupid)? It would be good to compare the noise against the Z1 and V1. I should be able to compare it to a Z1 tomorrow.
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Old April 28th, 2008, 10:44 AM   #8
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The same thought crossed my mind - that Sony had simply renamed '0dB' as '-6dB' - would they really do something so cynical (and stupid)?.
That's exactly what I meant when I discovered the grainy 0dB pictures from my Z7.
The 0dB seems to be equivalent at a 6dB on a Z1, in terms of grain and sensitivity.

Shame on Sony for that crappy Z7, they have lost all my confidence in their brand.
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Old April 28th, 2008, 04:28 PM   #9
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The LCD is also brighter than the Z1 at default, which will make most novices think the low light sensitivity is sooo much better when in actuality it is only marginally better than the Z1/FX1 at the long end
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Old April 28th, 2008, 11:13 PM   #10
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Bruce,

I tried it during the day outside, inside during the day, inside in low light at night.

All showed the same grain levels. Viewing the image on a 1920x1080 monitor, I was stunned to see noise floating around at -6DB in bright clear daylight. It was not screaming but it was there in the image and I was like...how can that be at -6db? At 0db, gain was in every lighting situation, and it just got worst when the lighting was not perfect. Especially in the shadows, this camera just loses self control in the shadows. Talk about getting dirty looking. The image just gets muddy.

If I remember right, I was able to put the camera at 0db, iris down a bit under exposed in a fairly well lit room, look at the image on a monitor and think... why is it so grainy and muddy looking? It's the first time that I see a camera at 0db, increase noise to that level simply because there is not enough light within the image (this is with the gain locked) The Canon A1 does not behave like this.

Maybe it's in the codec? Maybe it's in the way they bumped the chip gain to get that extra stop of light that they needed to say it was as good as the PD-170. I don't know anymore.

Paul
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Old April 28th, 2008, 11:18 PM   #11
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Mike,

Those images are dead on. That is the noise I see at 0db. Even at -6 it is still way too high in my opinion.

Especially for this level of camera.

Well, at least it's higher end to us, maybe not to the studio that uses full boat XDCAM's, but still, come on Sony. It still cost me almost double what a new Canon A1 would cost.

Paul
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Old April 29th, 2008, 12:01 AM   #12
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Paul, As far as noise I am just not seeing those same results. I am seeing it pretty crisp at 0db as far as electronics go. i have seen quite a bit of the blurring, backfocus and CA in harsh lighting in our footage, but the images have been very clean at 0-6db @ 12-18 the grain pattern seems to track the Z1 very closely and is the type of grain I sort of like. I used to be a Canon Fan boy in the XL1/GL1 days, but when you gain up on Canon electronics the grain pattern is no where near as appealing. If I were shooting light controlled setups, in this price range, I would go Xl-H1 but for available light shoots I couldn't see anything but the Sony cams.

If Mike is getting that kind of grain shooting his siemens chart at those settings I would think there was something defective.
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Old April 29th, 2008, 07:11 AM   #13
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Detail -
manual set-
off
I think this will help reduce the grain and crowling ants.
I shot a basketball training camp Yesterday 1080 30p Z7 / 720 60 EX in a gym no lighting footage look great
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Old April 29th, 2008, 12:09 PM   #14
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I did some more tests and then spoke to Sony this morning - they suggested resetting the camera (no effect) and then offered to replace it. I'll keep you updated on my findings when I get the new camera.
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Old April 29th, 2008, 07:13 PM   #15
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I am happy to report that I do not have any of the noise issues being talked about in this thread. I shot some pretty low light footage with 0 gain and then with -3 gain. Of course the -3 was even better. So that at least is a relief to me. I am discovering more and more that this camera is meant to be in manual mode. That means controlling gain, shutter and iris at the very least. Auto focus is not going to be good on this camera at a low light level either. Just wanted to report. Mike I am very happy to hear sony is going to replace your lens.

Bruce
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