XH A1 grain
 

hello,

i just got my xh a1 and can't seem to get the type of picture that i see samples of online. My picture is grainy. I have read on this forum about every thread i could find and have adjusted settings in manual and have gain down and i'm using some of the presets available here. It's definately better, but looks sd not hd. The colors just have so much grain to them. I have seen several threads started on this topic but i couldn't find a resolution.

Any help would be great i'm in a time crunch for shoot on friday.

jim

Pics
 

I am uploading two pics. They are a little skewed by my export but the picture looks the same.

This first one is in good lighting but look at the poor color, it's grainy.

http://shiftministries.org/vbs/Sequence%2001.bmp

This second one is in low lighting

http://shiftministries.org/vbs/Sequence%2002.bmp

Do i have a bad camera or am i missing something?

Hi Jim, are you certain that the AGC slide switch is set to the Off position?

Yes
 

Yes i just double checked. Can you see what i'm talking about in the samples?

Jim, I would say that the pictures appear grainy to you because this camera needs more light than is available in either one of those shots. They don't appear grainy to me so much as dim. These Canon HDV cameras can produce extremely sharp and clear images if there is ample light to work with. Without enough light their video gets sorta dusty (for lack of a better word).

I was taping with the XL H1 recently and accidentally had the gain turned on- now THAT was some grainy video. These pictures, there's just not a lot of light.

Other shots online
 

i just keep seeing other shots that look so much smoother. There is one i saw last night in a thread here of a guys snake and it was dark, but looked great.

There are many factors involved. Light is fundamental, but there are also custom parameters in the camera that you can adjust to achieve best results in particular conditions. Take time to read other posts on the forum. There is tons of useful hints and tips here. Experiment with camera's settings and both noise reduction options.

When you say you have gain "down", does that mean -3db?

Are you saying that the noise is obscuring so much detail in the image that it looks like standard definition? The frames you posted don't bear that out.

I don't see that much noise in your stills, although I hate to see interlaced. Noise can be caused by a warm sensor (30+ minutes of shooting), narrow spectrum light (tungsten), or dark scenes (low key). Your stills obviously had the latter two, and probably the former. If you want a dark image with low noise, it's best to shoot overexposed then burn it in post. If you shoot underexposed, you're reducing the signal ratio.

-3 db
 

i shot at -3db and only shot each one briefly and hours apart. What do you mean by burn it at post. I use premiere CS2. What can i do there to correct some of the picture. Also what can i do about interlacing. Sorry for silly questions i'm just trying to learn.

thanks
jim

Hi Jim.........
 

Hmm, well, can honestly say that's some of the worst A1 HD I've ever seen (heck, my XL1s takes better video than that!).

No idea what the banding I'm seeing is about (if that's what Daniel means by interlace) but yep, it's horrible alright.

I haven't shot a lot of A1 stuff in bad light, so can't really comment, but one test you really ought to do is:

Get a sunny day, go out when you've got blue sky, white and fluffies floating by, and shoot some of the most complicated stuff you can find @ -3 db. Forget all the presets and other stuff, just let the camera do what it can do on it's own.

Look at it on a REALLY good HD screen (straight off the camera - no NLE) and see if it looks anything like that stuff you posted. If it does, you have a serious camera problem. If it doesn't, you have a serious light/ presets/ other problem.

I normally shoot in really good light (hey, that's when everything looks so great) and can assure you that the picture from my A1 on a true HD screen just blows your socks off. Not a trace of grain or banding nor anything else whatsoever. And yes, I shoot 50i ,'cos it's cleaner(IMPO).

If you don't do that test, you have no benchmark against which to measure anything.

Just my 2 cents.


CS

I agree with Chris hook the camera up to a HD monitor and go through all the settings. This will give you the opportunity to see what combinations work and don’t work. Also it is a fun way to learn the camera and experiment with all the settings. Don’t be discouraged I went through the same process and now have great results with the A1.

To get a good shot you have to set-up a good shot, and that includes appropriate lighting for effect you want to achieve. How does the footage look on a TV? Hard to say what the deal is other than that the images are not great - with out knowing the full parameters of the shot, and keep in mind that stills from video will rarely look as good as stills from a real still camera.

What were the camcorder settings you used in the images?
What were the presets?
The lighting?
White balance?
What were the exposure parameters (you may be able to read them from the data code)?

Considering the gradient in the interlace artifacts, were these captured from a sequence that include both pan/tilt and zoom?

To help out a bit, I de-interlaced Mr. Simpson's image. here it its. You should also correct the aspect ratio to 1.33 which is HDV 16:9 (for a 1440x1080 image)

http://www.notomatofilms.com/1.jpg


Doesn't look terrible to me. I am curious as to your settings? Are in 60i? 30i? 24f? DO you have noise reduction on? What gamma curve are you using? Do you have any gain turned on? Are you sure you're focused right? What's your f-stop? Shutter speed?

Need a full list of the facts before we can diagnose.

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.

In the menu, change from 60i to 30F or 24F.

Specs
 

First of all i have a hd monitor that i have hooked the camera up to and played with. The images are sharp but the colors look grainy. Hope that helps some.

As far as settings.
In the first shot
i used the preset panavision
-3db gain
fstop unsure
shutter unsure
White Bal A
AGC off
AWB off
60i

On the second shot
i used the preset standard film
-3 db gain
fstop 1.6
shutter 1/100
White Bal A
AGC off
AWB off
60i

I just shot some outside footage and i'll load a pic in just a moment.

Hope this helps. I appreciate all of the helpful suggestions.

jim

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

If you're shooting 60i your shutter speed should be 1/60.

Sure. If you mention which terms require clarification, I'm sure someone will be happy to help.

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:

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.

Also if you shoot 1/60 as Bill suggest instead of 1/100 you will have more light.

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.

Exactly how can tungsten lighting cause noise? Please elaborate. I've never ever heard this before.

Bill

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.

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.

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."

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

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.

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

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.

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.