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Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


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Old September 11th, 2007, 12:08 PM   #16
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Daniel

Daniel,
Can you better explain what you are saying, i am new to the terms and while i am reading everything i can i'm still way behind.

thanks,
jim
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Old September 11th, 2007, 12:48 PM   #17
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If you're shooting 60i your shutter speed should be 1/60.
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Old September 11th, 2007, 12:50 PM   #18
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Quote:
Originally Posted by Jim Simpson View Post
Daniel,
Can you better explain what you are saying, i am new to the terms and while i am reading everything i can i'm still way behind.
Sure. If you mention which terms require clarification, I'm sure someone will be happy to help.

Quote:
In the menu, change from 60i to 30F or 24F.
First, the easy part: I hate interlaced video. Toward that end, I recommend that you shoot progressive by changing the settings in your camera. Hit Menu, go to Signal Setup, then Frame Rate, and change it to 30F or 24F.

I also said that narrow spectrum light, e.g. tungsten, causes noise. What I meant by that is that "indoor" lights cause noise. Usually nothing can be done about this, but it's important to be aware of.

The part of my post that was probably most difficult to understand is this:

Quote:
Originally Posted by Daniel Browning View Post
Darken with effects. Getting noise-free digital video in dark scenes is a bit of an art. The easy way out is to just use some noise reduction software like Noise Ninja. A higher quality solution is to overexpose without blowing highlights (that means the dynamic range of your lighting should be even smaller than the already small range of the camera), then darken it to the level you want in post.

Doing it that way gives the sensor a much higher signal-to-noise ratio, which yeilds far fewer noise pixels.
I'll re-state it in another way, but first, let me say that shooting dark video is hard. Much harder than bright video. You could save yourself a lot of trouble if you shot bright video instead of dark. For example, the stills you posted would have been vibrant and noise-free if you had increased the exposure by at least three stops.

However, your artistic vision should be the primary determination of how a frame is exposed, not the limitations of your camera. (Sadly, the reverse is often true.) So the rest of my post deals with how to get low-noise images when you've decided you want a very dark picture.

First, increase your exposure by three stops (e.g. f/5.6 to f/2) so that the picture is three times brighter than you want it to be. Avoid blown highlights if you can by changing the lighting, but if you're shooting available light (as I do for weddings), then you may have to make some compromises. This, of course, requires that you have sufficient lighting in the first place to increase your exposure at all. If you're already at the limit of the camera (1/48, f/1.6), the only way to increase exposure is by increasing gain, which would increase noise. In that case, there's nothing you can do (short of adding lights or a MUCH more expensive camera).

Then, in Premiere, reduce the brightness using effects until the video looks as dark as you want. It will add a lot more time to the render, but it will reduce noise.

The other method for reducing noise is to use Noise Reduction software. The camera has some built-in, which is good for convenience, but I prefer to apply it in post, even after HDV compression has taken its toll. As I said, Noise Ninja is good and inexpensive, but there are many others.
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Old September 11th, 2007, 12:58 PM   #19
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Also if you shoot 1/60 as Bill suggest instead of 1/100 you will have more light.
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Old September 11th, 2007, 01:40 PM   #20
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Which shooting mode did you use?

Grain is caused in large part by slight variations in individual pixel properties (e.g., sensitivity and dark current). These show up more in large expanses of a dark shade.

Slower shutter speeds can make grain more visible thanks to longer integration of dark current.
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Old September 11th, 2007, 05:39 PM   #21
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Quote:
Originally Posted by Daniel Browning View Post
I also said that narrow spectrum light, e.g. tungsten, causes noise. What I meant by that is that "indoor" lights cause noise. Usually nothing can be done about this, but it's important to be aware of.
Exactly how can tungsten lighting cause noise? Please elaborate. I've never ever heard this before.

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Old September 11th, 2007, 07:23 PM   #22
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Exactly how can tungsten lighting cause noise? Please elaborate. I've never ever heard this before.
Tungsten lighting generates more noise is because it has lots of red and very little blue. That gives the blue channel more noise as a matter of course, but what really makes it bad is when the shot is white balanced. That raises the gain of the blue channel, making a lot of noise visible.

One solution is to add an 80A lens filter, which cuts the red and green down to the a level closer to blue, allowing the op. to increase exposure and get a more even amount in each channel. However, it would not be worth it if it meant that gain had to be increased to compensate. To make matters worse, there is a lot of variance between tungsten lights, and different types of tungstens are frequently mixed on the same location.

Fluorescent lights don't have such disparate RGB levels, but the unit-to-unit varience is even more random than Tungsten.

Of course, all of this is relevant only for available-light shooting. Under controlled circumstances there are a wide variety of ways to covercome indoor lighting: daylight balanced lights, lights gels, more exact matching of lens filters, etc.
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Old September 11th, 2007, 08:39 PM   #23
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Like Don said, noise is mostly visible in dark, shady areas. To reduce it you can also make your scene more contrasty by pointing more light into areas that matter more.

Good thing is Canon's HDV cams exhibit more natural, filmic type of noise (largely thanks to high resolution sensors) than other brands. Noise always atracts more attention in static shots, but perception in motion is different story.
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Old September 12th, 2007, 08:29 AM   #24
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Exactly how can tungsten lighting cause noise?
I doubt that in normal applications it can directly, short of causing a heat issue that results in more thermal noise. I believe it is more a secondary result from typical (not studio) tungsten lighting encountered in the field.

In typical home, many event, and available light situations, tungsten light is often associated with low light levels, and perhaps the use of dimmers. Typical available tungsten light is rather warm, more like ~2700 K color temp and lower if dimmers are used (not the ~3200 K of photo floods). These situations can result in noisy images resulting from excessive use of gain, both to provide an acceptably bright image and to achieve white balance.

I wonder what the "native" or optimal lighting color temp is for the A1? 3400K, 5500K, or something in between. By optimal I mean the point where the dynamic range and noise of the CCD and amplifiers is "best."
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Old October 5th, 2007, 06:17 AM   #25
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A1 Noise

I have same problem with my 1 week old A1. I too cannot replicate the type of quality as I have seen on-line but I am thinking its user error. I dont think its the camera because there are similar complaints from others.

I am importing into Final Cut Express HD through the downconvert setting. My easy setup is set to NTSC DV

I see the same type of grain when pausing the image and sometimes when playing as well. I dont have an HD monitor/tv just my imac G4 screen which is usually really good.

I havent tried the -3db setting.
I tested in really dark areas @ 6db and its ok but not perfect. Tell me what you think or suggest
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XH A1 grain-noise1.png   XH A1 grain-noise2.png  

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Old October 5th, 2007, 07:48 AM   #26
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Remember it is a video camera, so best to judge actual video, not still frame grabs. In many cases, the video posted as a positive example is something the shooter is proud of, it represents the camcorder and settings at their best.

The files look normal to me, considering you are shooting in the dark. Some folks adjust presets, including NR and coring as an aid in managing noise. This is discussed in a number of other threads and in the presets forum as well. I think you would be well served to browse them.

I think many folks have too high expectations as far as using camcorders (any camcorder) in poor light/the dark, and in the case of the A1, using it as a point-and-shoot out of the box. While it has a point-and-shoot mode, it is not intended as mainly a point-and-shoot camcorder.

Without regard to details of you Mac, in general a PC is a very severe environment in which to view video. Most PC graphics/display systems are not designed or calibrated with video in mind, and the viewing distance is very close, typically arms length.
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Old October 5th, 2007, 05:50 PM   #27
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That was my sentiment but I guess I was hoping for a miracle. I have been in the video business for 24 years and have waited a long time for digital and HD and I guess I wanted more. Its still very good for complete darkness and without tweaking the settings. Glad to hear this is normal for the camera. Thanks
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Old October 5th, 2007, 11:25 PM   #28
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The pictures I see here are extremely underexposed -- by many stops.

You need to open your iris all the way, slow your shutter speed down, and turn your gain up, in that order, to cope with darkness. But before any of those, add light!

Learn to use your exposure zebras. They're your exposure meter for a video camera. You can't judge your exposure by looking at the lcd screen -- you need the zebras!

Any time you underexpose, it will get nasty. Get the exposures right, first.
Nothing else will help if you don't get the basics right. Don't worry about progressive and profiles and custom settings until you've learned the basics.

This camera shoots beautiful images. But it needs your input to do it.
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Old October 7th, 2007, 06:52 AM   #29
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I agree its underexposed but that was intentional to try and avoid grain. Iris was all the way up. Gain was +6db. If I went any higher, the image fell apart.
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