Does the GL/XM2 produce more grain than the VX2000, or is it just sharper? at DVinfo.net

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Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


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Old September 7th, 2002, 03:39 PM   #1
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Does the GL/XM2 produce more grain than the VX2000, or is it just sharper?

It's all in the title.
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Old September 8th, 2002, 01:10 AM   #2
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How would more grain equate to a sharper image? I'm not sure I understand the connection here.
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Old September 8th, 2002, 02:20 AM   #3
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I think he's asking a question that barry touched on in his review of the Gl2. Alex search for that article, I think it's pinned at the top of th GL2 forum. Barry mentions he noticed more grain but on closer evaluation found out that it was just that it was sharper than grain on his other camera (Xl1s I think it was)
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Old September 8th, 2002, 06:30 AM   #4
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Other things equal, smaller pixels can result in an earlier appearance of fixed grain and random noise in an image. Thus, I would expect the GL2 to exhibit grain earlier than the VX2000 (which has a larger CCD). Whether or not this is a problem depends on the specifics of the shot and the ultimate use of the footage, and will not be an issue for most users.
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Old September 8th, 2002, 09:12 AM   #5
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Yeah, I mean, if the image is sharper then any grain will be more noticeable, as Barry said (If I remember correctly). What you say certainly makes sense Don.

I bought an XM2 without really checking out the Vx2000 first hand - the XM2 is a lot cheaper here in England, and I couldn't really justify the extra cost, especially since the XM2 has a lot more features than the Vx2000.

I'm a image clarity purist though, and I'm just trying to reassure myself that the XM2's image is at least almost as clean of noise as that of the Vx2000 (in good light, I realise the Vx2000 wins out at lower light). It's basically a niggling voice at the back of my head saying that although the Vx2000 doesn't have a lot of the features of the Canon, and is a lot older, that maybe it would be better for the sake of it's superior picture quality (if indeed that is the case).

I've obviously compared a lot of the still picture's of the two, but I've not seen a video comparison.

Does anyone have 1st hand experience of the video quality of these two camera's?
(I've searched on here, but found no direct, to the point comparisons).

Alex
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Old September 8th, 2002, 12:25 PM   #6
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Alex

In good light, the gl2 exhibits almost no noise whatsoever, I find the images to be as noise free as the xl1s, which I think has one of the cleanest images in this category. The gl2 in comparison to the pd150 showed slightly more electronic "sharpening" althought the noise level appeared to be about the same. With a slight decrease in sharpness as a custom preset, I think the gl2 would probably show Less noise than the vx2000...and certainly no more.

In lower light, the gl2 does show more noise when set to default, but I think the sharpening is the culprit here.With a -2 sharpness adjustment it is on par with the other cameras. I think produces a sharper, cleaner image in moderately low light situations. In "no light" situations the gl2's lower sensitivity shows itself, and it is difficult to get good images.

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Old September 8th, 2002, 06:29 PM   #7
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Thanks Barry, that's very reassuring.

The low light performance definitely isn't worth the other trade off's like manual controls and 20x lens etc.

Would you say the gl2 is higher resolution than the vx2000? What about in frame mode, as I have noticed pixellation in this mode?

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Old September 8th, 2002, 09:25 PM   #8
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Alex

I think they are relatively in the same boat as far as resolution goes (again I am speaking of the pd150 which I understand is the same guts as the vx2000). The Gl2's specs are slightly better, but I don't think you could discern a real difference relative to resolution.

Remember the limiting factor for resolution is typically the DV format...its compression level and frame size. The gl1 and xl1s I think sit slightly below the threshold of where the "format" becomes the limit (using pixel shift to make up some of the difference.. the gl2 is definitely above it, as is the pd150. You really have no worrys about great image quality with either camera...it's really the feature set should make your decision.

I use the gl2 exclusively in frame mode and have seen nothing resembling "pixelization". There is a slight loss of vertical resolution...which can translate into more line "flutter" -- but true pixelization would indicate some other problem. I think the gl2 in frame mode is as close to a perfect image as the consumer minidv format is going to give us until we see true progressive scan...and what I've seen so far from the upcoming panasonic 480p (ag-dvx100) doesn't even hint that that is going to be the case anytime soon.

Again these comments are relative to resolution only.. while I like the natural color of the gl2, I feel it is somewhat limited in the sense that it is difficult, or impossible to "oversaturate" it. While this may not seem like a noble goal, having the range to get there means that you have the range to get where you really want it, and the gl2 is slightly less flexible in this area than the pd150, or the xl1s. While this can be fixed in post, it would be nice to get it at acquisition.*

That said, while I am consistently getting the best footage I have seen from any camera (in this category) from the gl2, you can't go wrong with either camera.

Barry


*Anecdotally, I have been experimenting with a some pretty strong color and gamma tweaking in FCP, and the gl2 image seems to be more maleable that my gl1 or xl1s...this may just be my imagination..I don't even know if it's possible, but the stuff looks good.
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Old September 9th, 2002, 08:17 AM   #9
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Thanks again for your reply.

When I said pixellation, I was referring to something I noticed while I recorded myself playing the drums in frame mode. I could see "stepping" on the diagonal part of my shoulder, as you would expect in a low resolution non anti aliased edge. It wasn't in the best light, but still, I noticed it and didn't like the look of it much!

I've not really had any complaints in the white balance / colour saturation area. After reading about Heidi's troubles the first thing I did when I got it was tweak it right over to the red side to see if it could do it, and it responded very well IMO...it was far more than I would want to use anyway.

One last question which isn't really related. Someone (I forget who) said that they recommend shooting at -3db Gain for an even cleaner image than 0db (which I would assume to be best).

Firstly, are they talking image gain, because my XM2, only has 0, 6, 12 and 18db settings.

If they are talking colour gain, then I don't see any actual values represented on the bar in the custom preset setup. Is one stop = 3db ?

I'm confused about it anyway, there are only two types of visual gain right ?

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Old September 9th, 2002, 09:14 AM   #10
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The -3db gain adjustment refers to the xl1s, which has the capability. The gl2 doesn't.

The stair stepping (or aliasing) issue is a DV thing again, largely due to format size, and most camera's I've seen will do it on High contrast diagonal edges. You can control it somewhat by turning down the sharpness and raising the setup... though the real issue is contrast. The second day I had my gl2, I went out to the bay and shot some saleboats, I was quite impressed with how it rendered the diagonal edges of the sails and ropes...silky smooth with no stairstepping whatsoever. It was a foggy day though.

I thinkl the stairstepping on the gl2 is less of an issue than with the xl1s and far less than the gl1.


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Old September 9th, 2002, 10:19 AM   #11
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Barry,

I follow your posts with great interest. I feel your observations are very astute and show great insight into the workings of the GL2. However, I'm a bit confused on your last post. So, I'm probing a little deeper.

You shot the sailboats on a foggy day (low contrast) and had minimal stair stepping. But raising the setup should increase contrast and thereby increase the stair stepping. What happens when you lower the setup?

Jeff
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Old September 9th, 2002, 11:58 AM   #12
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Lets See. When I adust the setup level upward on the Gl2 (I'm doing this as I type) the shadow areas lighten (actually the whole image lightens as if you were adjusting the black point upward on a photoshop curve) with the white point staying about the same, so I would call this a decrease in contrast, not an increase.

That said, I am pointing the camera at some pretty high contrast edges around the studio, and I can't get the camera to stair step AT ALL (darn it!) with the camera at default or with an adjustment. So I really can't test my theory. Come to think of it, the only time I've seen stair stepping has been on some heavily burnt out highlights against a dark background.

Now when I view the image on the flip-out LCD rather than a monitor, I can see a difference between the default, and a preset with -2 sharpness, and +1 setup..in that the default appears to stair step slightly, so I think this validates my theory.

But I'm going to have to stick by my main thesis that this is not much of an issue with this camera (unless your lighting is messed up in the first place).

As you rotate the camera so that a high contrast edge approaches horizontal, a "flutter" occurs which looks a little like stair stepping, but this appears to be more a product of the scan lines of the monitor as anything...essentially just a moire introduced by the resolution of the output device (we see this often when printing high resolution postscript images on lower resolution devices).
As the line being rendered gets closer to horizontal the scan lines have to slice off bigger chunks of the actual line and you start to see a problem.

Anyway, I tried adding the adjustment in this case, and it seemed to help a little, essentially adding a little blur to the sharp edge. I also tested it on the xl1s with similar results...Perhaps the GL2 MIGHT show a little more of this type of artifact, as the camera acquires with more resolution and thus the edges are sharper (in addition to the camera's greater electronic sharpening), but I think the issue in this particular case is really with the output device. In theory this type of moire can be produced by the DV format itself (check out this ag-dvx100 footage someone posted last week if you want to see it in action...OUCH!).

http:66.78.26.17/~reli/24P/30P.avi

...and thanks for your kind comments.

Barry
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Old September 9th, 2002, 03:19 PM   #13
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Hi again

"Barry,

I follow your posts with great interest. I feel your observations are very astute and show great insight into the workings of the GL2."

I'm with Jeff on this one! :)

I think you're right, it's bound to just be the TV I'm outputting it to (Sony Trinitron), either that or a combination of dv and poor lighting.

Incidentally, while I'm on the subject of lighting, generally how do you light something so that it has that professional look? i.e. won't look out of place in a well made film. I know this is the biggest can of worms ever, and some people's whole job, but I just wonder if there are any guiding principles you use, that can perhaps be achieved with a few household light sources and some experimentation.

i.e. do you put a warm diffuse light over the background and use a light to highlight a subjects face in close up.

I don't want to spend a lot of money on lighting gear, and I'm interested to see what I can get away with for short's etc, where a lot of natural lighting is all we have to work with.

Hope that all makes sense...

Thanks
Alex
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Old September 9th, 2002, 04:23 PM   #14
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Alex

You're right, this is a big can of worms, and one that can't really be "taught" or "learned" in this type of forum. I come from a lengthy still photography background (fashion, advertising), and while a lot of what I've learned in the past 20 years applies to film and video, the world of cinema has a lot of requirements that really up the ante relative to lighting skills.

Considering your stated goals, I'll outline an approach that might work for you, rather than answering your question directly:

I occasionally teach classes to small groups of amateur photographers who will probably never turn on a external light source to take a picture. The thrust of these classes is on learning to "see" the light, rather than trying to "create" the light. I think if you look at a lot of foreign, and independant film (even some major studio work), you'll find a trend toward use of natural light (or at least the look of it).

Start by viewing some films with this aesthetic, if possible on dvd or video so you can analyze how light is being used and where the light is coming from. How many sources, colors? does the light appear soft, or are there strong shadows? If there are shadows, do they look filled, or left alone. Notice how the actors move through the light...are they always lit, or do they move in and out of the shadows and highlights. When they move into the shadows, does the screen go black, or is there something in the background that is lit which helps to maintain their sillhouette (pop quiz material!) What happens when they turn their heads. What happens when the camera moves....make some notes.

Next pick a simple scene from the footage that you particularly like, maybe with one or two characters, and try to duplicate it. Don't pick something with 20 lights...find something that takes place next to a window or doorway so that the light source takes care of itself...the learning comes from how you adapt to what is there. Get yourself some pieces of white and black foamcore to add fill or subtract light where necessary, you'll be surprised what you can do with just these simple things. I'd also recommend a simple frame to stretch some white cloth or a shower curtain liner to use as diffusion. View it on a monitor to see the difference between what you see, and what the camera sees.

Learning lighting is a lifetime occupation, and movies have always been an great source of inspiration to me. It may take you some time to even know what to look for, but you as you practice and learn, both the questions and answers will become more clear.

For starters, take a look at Steven Soderberghs "Traffic". Huge chuncks of this film were made sans lighting. Also "Timecode", by Mike Figgis, which was one of the first DV features, shot in single takes with 4 cameras and I think, no lighting. Just saw a great french film "Read my Lips" which has a very natural look overall, although there is some judiciously used "hollywood' lighting on some key scenes. Also, to see where DV can go, check out Chelsea Walls...I kept trying to guess whether it was DV or not (it was). Beautifully shot (definitely not one to try as your first project, though).

Good luck...perhaps others will chime in with some books or ideas...although I think we are starting to move out of gl2 category and this thread's topic... Try a search for lighting here on dvinfo to see what comes up.

Barry
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Old September 13th, 2002, 12:19 AM   #15
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Back to Original question,

Go here: http://www4.big.or.jp/%7Ea_haru/temp020829/0208_3CCD.html
and see the difference in low light (2 stops underexposed) between the VX2000 and GL2.

The GL2 runs out of light far earlier, and exhibits noticeably more grain in "medium-low" lighting than does the vx2000. Otherwise, in good light, their pictures are very close. The GL2 is a very capable camera.
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