Max,

Have you tried any of the methods discussed in this thread and others to rectify the problem, (unfortunately this thread turned into a mudslinging affair, but I think there is at least one other that might offer some advice)

The moire artifacts you are seeing are a by-product of higher resolution and the progressive scan system employed by the xl2, and are not, in fact a defect of the camera. In truth, they are more typically caused by the output device (monitor, TV) than the camera itself, but the higher resolution of the xl2 will cause more moire with more output devices than the xl1s (simply because it is more capable of "seeing" fine patterns than the xl1s is.)

The way to make the image look like the xl1s is to, well... lower the resolution of the camera by a variety of methods including the sharpness and detail settings, adding some light diffusion (or low pass filter) over the lens, or moving/zooming to alter the frequency of the offending pattern.

Hope this helps.


Barry

I agree with all that Barry suggested but have to say that if the problems you are describing are indeed as severe as you say, there could be a problem with your partiular unit. Obviously there is no way to know for sure by just your description. Do you have access to a store that has an XL2 that you can compare it to so that you can assure yourself that the camera is indeed working properly?

It's not a particular xl2 unit issue. Moire is definitely more noticeable in 24p. It does jump out at you, expecially in a handheld situation.

I for one am not worried about it. This thread has been a hoot to read! Good to see lot's of heated discussion. Hopefully Canon will weigh in at some point.

Ken

I know it is not an XL2 issue but the way it was described sounds much worse than what I have experienced with the DVX for 2 years and now the XL2.

The problem is not just the moire. The camera is also having serious aliasing issues. I was shooting an event and some kids glasses were jagged. The straight lines were dancing around. I tried adjusting everything on the camera but it did not change.

I have looked at the footage I have shot on an HD monitor and I am still seeing the same moire and aliasing.

I have returned the camera and went back to my old XL1s for now until I make the switch to HD here soon.

I have worked with higher end camera's that had a higher resolution than the XL2 and did not have a problem.

I am really disapointed with the XL2.

I am sorry to hear that. I really feel that there must have been something wrong with that particular camera. Good Luck!

Thanks.

I think I am going to switch to ocuar implants that records in real life ;)

I think I will see if they will swap the camera out and see if it is the camrea.

If anyone has some space where I can post video, I can provide few xl2 (uncompressed) avi examples of this moire problem at 24 fos. It's not just a minor, "sometimes it happens" issue. It is something a dp has to be aware of and must work around.

It is also not just one camera. Many people have experienced it, as I said before, if you shoot 24 fps with an xl2, the moire jumps out at you. Anyone who says it doesn't has solved the issue and should share their solution here.

On the plus side, the camera is still incredible. Not perfect, but incredible.

Thanks, Ken

Kenneth,

If the issue is moire and/or aliasing, we should be able to see it in a still frame. If you want to email me a few grabs, I'll be happy to post them for you.

I'm not sure I agree with you though. I've been using my xl2 for almost as long as anyone, and I'm familiar with moire in its many forms. Any issue I've seen can be tied to two things...the higher resolution of the xl2 (as compared to the xl1s) and SD monitors when dealing with progressive footage. But really I have almost never seen a problem, except when I know I should...like shooting bleachers at a baseball stadium, or a vent grating...things with definable patterns of specific frequencies.

As for the "aliasing" issue, I would go as far as saying that it has the lowest aliasing of any camera I own (3 different canons 3chips and a DVX).

And I've never made a single adjustment to affect the camera in terms of controlling moire or aliasing.

In reality, most of the issues I've seen have ended up being almost completely related to the monitor's processing of progressive footage. I shot and posted footage of san diego a few months back. When viewing the raw footage in my hotel room, I experienced exactly what everyone is commenting on. My shots of an empty Petco Stadium were a moire makers dream. But when I viewed them on my HD set at home, the problem was almost a non issue, even less on my computer (remember that this was a situation that should cause moire, and would have on any camera capable of focusing). That tells us something about the nature of moire's: always caused by at least two overlapping sets of patterns ---stadium seats>>CCD Block>>monitor array.

Yes you can argue "so what, I'm still getting moire, and I never saw it before". There are two answers to that. The first is that all of us who saw the crazy moire coming off the very expensive HD broadcast cameras at the Olympics track and field events this year are beginning to understand that moire is a fact of life with higher resolution cameras. (I doubt that the camera operaters were all begging NBC to give them back their old cameras...they'll learn to deal with the moire in exchange for the incredible detail that the new HD cameras can provide)

The second answer is this...now that you've seen it (it was always there before, you just weren't looking for it)...and you're probably very unlikely to be able to look past it now...so you can take steps to resolve it in the situations that warrant it...and because of that you are a better videographer with a better tool than you ever had before.

Anyway, please send along your frames...I want to see what you are seeing.

Barry

Hi everyone, what an interesting thread. A lot sounds complicated to me as I'm still learning the ropes but informative nonetheless. I have yet to shoot on tape but I have been switching on the camera and looking through the viewfinder monitor. I have a PAL cam by the way. To me when you view in wide mode it looks a little "jaggy". I'm not sure if this is just down to the little monitor or not though. is there an option on the cam to shoot in progressive or non progressive, or does it shoot in the best method as standard?

I'd definetly like to see more pics and this has made me want to go out and just film footage of brick walls as a test.

On a final note, I just wanted to say I respect everyone's opnions here. They know far more than I and I don't think there was any need for that fella (who's name I've forgotten) to be so rude to everyone trying their best to help. It is a worrying thing, but one that I hope is easily fixed through learning about the cameras abilities.

There's always the obvious steps to avoid moire and similar type of distortions. No fine line patterns, of any kind, at any time, on the set.

This was actually my first request to the girl that is in charge of costumes and accessories on my next project (that and no white).

No fine stripped ties, pants, shirts, etc. No blinds (they're fine in close up but when shot wide they become a nightmare) and as a general rule of thumb, nothing with a strict and regular pattern (lines, grids, etc.).

Organic and irregular patterns are fine with video (to some extent) but repetitive and identical patterns tend to cause problems so far from what I've seen.

If you're shooting fictional stuff, this is something you should test BEFORE the shoot, since you have the ability to change it if it causes problems.

Thanks for the offer Barry, but...

When I play the captured aviin Premiere Pro 1.5, the moire is there. If I still the picture from the captured avi in Premiere Pro 1.5, I can see the moire patterns. When I choose Export Frame and open the bitmap, the pattern is gone. This is very interesting. Can someone explain?!

<<<-- Originally posted by Kenneth Irvine : Thanks for the offer Barry, but...

When I play the captured aviin Premiere Pro 1.5, the moire is there. If I still the picture from the captured avi in Premiere Pro 1.5, I can see the moire patterns. When I choose Export Frame and open the bitmap, the pattern is gone. This is very interesting. Can someone explain?! -->>>

Are you viewing on the PC or on the NTSC monitor?

Kenneth,

this is exactly the issue that colin first encountered when he started this thread...he was seeing it on his monitor, but when he looked at a still frame it wasn't there...at which point he produced deinterlaced frame to show what the problem looked like....as if this proved something.

De-interlacing is like halving the resolution(vertically)...essentially you are placing another lower frequency pattern over the the existing pattern...this will bring out moire's where none actually exist in the original pattern (you may like to try this with your image...I tried it with some that I did myself trying to figure out what created the effect colin was seeing.)

can someone explain?...this issue is the one I keep harping on...in clinton-ese...its the monitor, stupid...(no offense meant here)...why you are seeing it in premiere and not in the still frame is that thay are most likely being viewed at different resolutions...let me offer you an illustration

go to my public folder

http://homepage.mac.com/barrygoyette/FileSharing23.html

in it is a file called moirebit.tif

open it in photoshop or some viewer that will allow you to zoom. Start by viewing it at 100%. you'll note that it is just lines...no moire...just lines, none in the image...this is equivalent to a camera image that doesn't have any moire in it. Now zoom out step by step...and you'll notice that gradually small moires will start to appear, and the more you zoom out that the moire will gradually get more noticeable and change its form. This is a very coarse example of what is going on in your case...the moire isn't in the image...its in the monitor's interpretation of the image based on certain pattern frequencies (image and monitor).

I hope this helps.

Barry

edit: don't try this in apple's preview program, it won't let you zoom out far enough, and it has a neat little anti-aliaser that will smooth things out...the effect is much more obvious in photoshop.

thanks Barry none taken :)

So...the recorded image is fine and the moire is simply a monitor interpretation? If so, then the viewfinder on the xl2 has the same problem. I just played back the tape and the patterns are visible in the viewfinder. What type of monitor would not interpret the footage as having moire?

Ken

I'm curious about the monitor thing too as I will be purchasing one at the end of the month. Would most 7" or higher TFT monitors show this kind of thing? I'm asuming this is all trial and error really and knowing how to account for such problems

Yes the viewfinder on the camera, being relatively of low resolution will exhibit much more moire than say my sony wega HD set. Theoretically a monitor that displays in progressive scan at the same resolution as the source would be the optimum. So, for instance a quicktime file played through the quicktime player on a computer monitor at full size wouldn't have a problem (if there was no moire in the image to start with). I don't know that there is a "perfect" monitor out there, but the higher the resolution the better is a starting point.

The other ( and more realistic ) option is to shoot for your intended monitor. Canon's old frame mode did this...essentially lowering the vertical resolution 25%. We all thought it was a defect until Panasonic came up with it as an "option" on their progressive scan DVX to help eliminate line twitter and other problems related to moire. You can lower the vertical resolution on the xl2 in the same way, or employ a number of other ways to lower the camera's ability to see fine detail and patterns.

Barry

are most monitors labelled "high resolution" progressive scan? I haven't really seen any with progressive scan listed as an option.

will lowering the camera resolution be harmful in any way later on when editing?

The problem is most people do not have a high res monitor to view the the nice images that come from the XL2 so all of you wedding and event people out there are going to have a tough time getting a good looking product for your clients.

Unless you could give away a nice monitor with each wedding package so they could enjoy the nice picture on the XL2.

I have been shooting on a Sony DSR 570, 2/3 inch chips, I would expect it to be as high if not higher in resolution than the XL2 and I do not see the same problem. I shot them side by side at the same image and did not get any aliasing or moire on the Sony and the canon was going crazy. Both were viewed on the same monitor.

Max

A few questions...the comparison you made...was the xl2 in progressive mode or interlaced? There is a substantial difference in resolution between the two, and most people who have seen problems have reported it in progressive. The DSR-570 is a 60i camera, so regardless of its potential resolution, it is a different animal. Interlaced video uses a pixel averaging scheme which effectively blurs fine details like those in a moire inducing pattern. (there used to be an explanation of this linked at adam wilts site, but I doesn't appear to work any more).

Second did you try the low detail setting? Both canon and Panasonic recommend it for viewing on an SD monitor.

Finally, are you shooting in 4:3 or 16:9? If you are shooting in 4:3, my experience is that the in camera sharpness is set too high on the xl2, and needs to be lowered to achieve a truly "neutral" sharpness position.

wait...I found the article...I think it might help explain some of this...

http://videosystems.com/shoot/video_...now/index.html

cheerio

Barry

Thank you so much for that info. I think I will swap out the camera for another one and see if I just have a bad model.

Thanks again.

Well put Barry, a good and sensible explanation.

I've often wondered myself when people report about different findings, that there are so many issues left open that it is almost certain that we will end up of talking of different things. For instance in this thread, when Kenneth said he captured an avi image to Premiere Pro 1.5, the issue of whether his monitor window was set to 100% magnification was not cleaar. And still, as Barry explaination clearly shows, this is the crucial point when discussing of what we see on the monitor.

What comes to the Xl2 viewfinder, it has obviously its shortcomings. Just recently I had the camera outdoors for several hours (in a insulated bag) and it was bit cold (around -5C), and I noticed the viewfinder became rather slow. As a result anything which was moving did not appear smooth. But, back home the recorded image was just perfect on the monitor. (My first experience suggests the Xl1 viewfinder tolerated better cold conditions in this sense. I had similar problems with the Xl1 only when it got below -15C.)

Lauri

thanks for the info on the viewfinder...I never would have suspected that the viewfinder would have problems with the cold. It gets cold here too, last night was a blustery 50F (+10C)...I had to put on long pants!.

Barry

I noticed what I thought was a moire problem with my XL2 when shooting in areas with a lot of grass or trees and a lot of times on rooftops. I have done a lot of research and found out that the more accurate term would be arftifacting. I sent my camera off to canon, which they replaced with a brand new one, I found that I had the same problem with the brand new camera. After much research, heartache and a long chat with the Canon regional rep I tried playing with the settings. I found this helped significantly. I lowered the sharpness and turned on the noise reduction which helped out significantly. I now can shoot an acceptable image in a grassy area which I could not to before. Just wanted to share with anyone else who might be experiencing the same problems.

Welcome aboard DVInfo.net Keving and thanks for sharing that tip!

Would you happen to have comparison frame exports?

I am unable to post any right this second as I am already behind on 2 projects but as soon as I get caught up I will definitely share some comparison pics.

<<<-- Originally posted by Marty Hudzik : Find it hard to believe that there would be problems already and it's not even officially released. -->>>

WOW these images are beautiful !!

I have never seen such images pulled from MiniDV !!

How did you do it... How can I do it ??

Thanks!

<<<-- Originally posted by Anthony Marotti : <<<-- Originally posted by Marty Hudzik : Find it hard to believe that there would be problems already and it's not even officially released. -->>>

WOW these images are beautiful !!

I have never seen such images pulled from MiniDV !!

How did you do it... How can I do it ??

Thanks! -->>>

Anthony,
What images are you referring to? I am asking because you quoted me in your post but I have no idea what images you are talking about.

What to do about it
 

I got a Canon XL2 PAL in december 2004. I love it, but noticed this moire on my pictures ( roofs and brickwalls) I phoned every expert here in Denmark, but coud´t really explane the problem. Then I was "lucky". A guy told me to submit this forum and so I did. I used days inside my head to create a question about my problem ( my english is limited ). And just before I started to write I found this discussion exactly about the moire problem that I was looking for. I´ve been using days to read all this. Wow, this was really professional experts words. But the more I read the more confused I got.
Am I stupid. Is there no conclusion to the moire problem.
Can I do anything, buy anything, change anything to minimize this moire thing.

Hello Per,

Welcome to DV Info Net.

<< Wow, this was really professional experts words. >>

Well, not all of it... the song lyrics I wrote, that was neither professional nor expert.

<< But the more I read the more confused I got. >>

Me, too. And I own this place!

<< Am I stupid. Is there no conclusion to the moire problem.
Can I do anything, buy anything, change anything to minimize this moire thing. >>

You are not stupid and there seems to be no conclusion. What is interesting is that this conversation ended last December and nobody has said anything since then. If anybody else has this problem, I sure would like for them to post about it here.

Meanwhile, I wonder if this is of any help:

I don't know if this will have any effect at all, but trying switching the Vertical Detail setting to the opposite of whatever it's set at right now. In the camera, this is on the 4th menu page under Custom Presets. In the owner's manual it is described on page 69. You might try Noise Reduction as well.

Remember after these settings are changed you have to activate the Custom Preset (a lot of people seem to forget that step for some reason). Let me know if this helps,

I think it's been said dozens of times here and elsewhere but it is a difficult subject and people get confused so let me try to summarize. There is nothing wrong with the XL2 with respect to aliasing. Sampled systems are subject to aliasing which appears as moire in a two dimensional image unless the sampled information is strictly band limited to less than one half the sampling rate. Many cameras (especially still cameras) have optical antialiasing filters. The Canon video cameras apparently do not. Thus they are subject to moire but so are most other video cameras. Look at TV (including HD) and you will see moire. There is absolutely nothing that can be done about it except to reduce the spatial high frequency component of your image before it reaches the sensor. This can be done with blurring or diffusing filters. If you want to get rid of aliasing buy a blurring filter (and don't complain about the loss of resolution - you'll lose some). Once aliasing is in it is in forever - it cannot practically be removed though it is possible to mask it in post in some cases.

Thank`s Chris and A.J.

I will try to do some shots in the comming weekend,, Denmark is when I´m off my job too Dark in the winterseason.
I will let You know if Your adwise helps on the moire problem.
A.J Thank You for a very concrete answer. I needed that during the discussion on this forum.
I understand that moire is a normal thing. I watch the Olympics too. I see it every time I turn on my TV, even in a very expensive movie produced by the Danish Television (DR), and I accept moire as an intergraded part of making video, but I just think the ammount of moire is much too high with my brand new, in all other parts superlovely XL2.
If it would be in anybodys interrest I have a shot as a very good evidence. I just don´t know how to link it to this page.
Sorry to bring this up again.

Per

Just to reiterate one of my earlier posts on this subject... quite often the moire you are seeing is more relevant to the viewing device than it is the the camera. The originator of this thread was unable to show us the moire in the image itself because there was none. The higher resolution of the xl2's progressive mode will cause interlaced monitors to produce a moire even when one doesn't exist in the image itself. Such is the nature of moires...they are caused by related pattern frequencies in the subject, imaging device and output device.

There are several ways to avoid them.

1. Take care when shooting fine repeating rectangular patterns, moires often occur at one or several zoom/proximity levels..quite often you can eliminate the moire by adjusting the zoom, or moving the camera slightly.

2. Use a low-pass or diffusion filter to take the edge off of the fine detail. (this will help for moire that is happening in the camera (rare)

3. Lower the camera's vertical detail, and/or adjust the camera's sharpness setting downward (this will help with moire produced by the output device from an image that contains no moire (most common type of moire). This can also be accomplished in post.

Barry

<<<-- Originally posted by Marty Hudzik :
Anthony,
What images are you referring to? I am asking because you quoted me in your post but I have no idea what images you are talking about. -->>>

Hello,

Here is the quote that I should have quoted:

<<<-- Originally posted by Clive Collier : This isn't a joke I'm afraid.

Here are some shots to show clarity of image which is very impressive:

http://www.showreel.org/XL2/xl2stills.html

Will post morray pattern in a moment -->>>

Sorry about that !