Colour bleed

[Jeff Donald]

Andre De Clercq' s post above just about covers it. It would be impossible to be much more specific without test instruments to analyze the video signal. Send the camera to the manufacture before the warranty expires. Good luck.

[David Deehan]

Jeff,

Thanks for the very prompt reply. I read Andre de Clercq’s reply some time ago but sadly don’t have such exotic equipment. Having read Andre’s posts in other threads makes me realise how limited my technical knowledge is.

Anyway, could you advise me if the symptoms I am experiencing are normal with XM2’s (or GL2’s), is a possible defect or operator misuse? I hate the thought of packing, insuring, posting and waiting only to be told by Canon that the camera is within factory specification.

David

[Jeff Donald]

Some of the shots may have a bit excessive color bleed. But it is really impossible to tell without the correct test instruments. If it were my camera I'd send it in. Be sure and enclose a tape with a couple of clips showing the color bleed issue.

[Chris Fangio]

I don't wanna be offensive, but I doubt that any of the XM2 users (and most probably the GL2 users, too) do NOT have this sympton of the bleeding colour.

I own a XM2, I worked with a friend's XM2 and we have two units in our advertising agency. Big surprise: all of them do have the colour-bleed-problem. We tried different setups but the bleeding of red colour is clearly visible. I'm almost sure that it's by design. This and the fact that you ALWAYS have to crop the image when doing picture-in-picture video or web-video with a PAL XM2 (remember the flickering line on top, we discussed the problem here) is very disappointing for me. Please don't mention the "wanted degradation" of the still image capabilities or I'll start crying. Don't get me wrong, I like this cam (beacuse I paid 2100€ for it) but I think that Canon could have done some things much better with no expense.

You'll have to live with it or buy another camera.

Chris F.

[David Deehan]

Hi Chris,

Could you confirm that the symptoms you experience are the same as mine, i.e. nearly 100% of all colour leakage is to the left and bottom of coloured areas. I notice very little to the right and top. Do you also experience colour bleed in blues and greens?

What annoys me and what convinced me to buy an XM2 (apart from reviews on this site) was a review in the “Camcorder User” magazine - UK edition - dated Dec 2002. A quote from this review is as follows “there’s not a hint of colour bleed, even on the usual suspects such as bright reds and blues”. Maybe they got a handpicked camera from Canon or maybe the Advertiser/Magazine conspiracy really does exist.

Both colour leakage and the necessity to crop all clips in post (PAL version only) have convinced me to change camera when the finances allow.

David

[Chris Fangio]

David,

as images say more than words, I'll try to capture some still images. Hope I'll make it on Saturday or Sunday to post some pictures.

Chris

[David Deehan]

Chris,

thanks in advance for taking the time to prepare some images for inspection. I'll hold off contacting Canon until after.

regards,

David

[Chris Fangio]

David,

I checked my captured files and found out that I have only frame-mode shots on this computer (and I saw you were using normal mode). But I remember shooting interlaced last week (fruits for a commercial). I can check this tomorrow in our agency if you want me to.

I also rember that someone posted frame grabs of his GL2 and this effect was clearly visible. I just don't remember his name (the pictures showed african people with colourful clothes if I remember right).

Chris

[Paul Doss]

This is really sad! I have been saving for a long time to get a GL2. I have seem this with footage that was captured from VHS. The reds and sometimes the dark blues bleed or ghost. Filters in post help a little but, very little.

I thought until reading this thread that wouldn't be a problem with digital source material. If I'm reading this right everyone has it unless the final product goes out to MPEG2. Seems the XL1s, and some Sonys have the same problem. Makes you wonder what cameras don't have it. Is it something we just have to live with? Or is there a camera that doesn't have it.

[Andre De Clercq]

David, all color encoded (PAL NTSC) footage generates some extra color bleeding because of the ectra analog color bandwidth reduction. The point is that the bleed is generally acceptable when it is not shifted w.r.t. the luminance picture. Once the bleed (resulting from DV sampling limits AND analog bandwidth limits) is shifted, the "shortcomming" comes to one side and becomes much more visible. In PAL, the extra vertical color bleed (allways downshifted) is, together with the further halved vert color resolution (two times!), one of the PAL shortcommings. NTSC only has the DV sampling limits and should apart from some color bleeding, not show vertical color shift. Like I already wrote in this thread, component playback should solve the shift problems, unless the DV codec itself would introduce some shift effects. On the XM1 which I was evaluating (and didn't buy) some time ago I reported the color shift problem (see my message on Dec 26th 2002).

[David Deehan]

Replies to the last 3 posts.

Chris, I would be grateful if you could post sample images of the commercial you shot last week.
Regarding the frame grabs posted earlier, would this be the link you are referring to: http://homepage.mac.com/bhardy3/PhotoAlbum8.html

Paul, don’t be too disillusioned. The colour bleed problem only crops up now and again. It doesn’t occur in every shot. Just avoid shooting saturated reds, blues and greens as much as possible.

Andre, I think I would need a degree in television electronics to fully understand your reply. Am I right in assuming that the colour shift you are explaining can be generated in the DV encoding process (by the camera’s hardware codec) as well as during decoding (i.e. playback). In my case colour shift is evident in the playback of some unedited clips both on desktop computer and television. It is also visible on a laptop (with a tft display). Would I be correct in thinking that a laptop display is purely digital (i.e. no digital to analogue conversion) and would therefore be equivalent to using the DV component player and component display you mentioned in a previous post. If this is true would I be correct in assuming that the colour shift I experience originates from the camera.
I just looked at your post dated Dec 26th 2002. It’s a pity nobody replied. I guess most people (including myself) didn’t understand its meaning or importance. What I find annoying is that my previous digital cam did not exhibit colour shift and it cost less than half the price of the XM2. Chris Fangio seems a little upset as well (see above post).

David

[Andre De Clercq]

David, your assumption is roughly correct. Indeed DV codecs (HW and SW) can show some color shift in addition to the bleeding. Your desktop playback experiment is not the best way to interprete color shift (or any DV picture artifact) because the decompression, deinterlacing and rescaling needs a "stripped down" DV image reconstruction in order to get the real time video on yr TFT screen. I think you better try to evaluate on a real component equipment. B.t.w. did you know that some DV VCR's have an Y/C delay adjustement possibility (like Sony DHR 1000..) Also some TV's and monitors have this feature (my home TV Loewe Arcada has it too). Of course this doen't solve the initial problem. Also many high end TV's have CTI (Color Transient Improvement) circuits which even solve the remaining bleeding problem for a good part.

[Bernd Binder]

Hello to All,

I am using my XM2 (PAL) now for 3 months. I have also registered a colour bleeding problem (not only red) under special conditions, f. e. red dressed skiers. It is visible on TV (Sony 100Hz) and on computer monitor. The bleeding is always on the left and bottom side of the coloured areas.
I have experimented with all possibilities of the setup – I don’t work.
Last week I brought my cam to Canon Vienna for repair. After 4 days I got back the cam. The diagnosis was: Everything with this cam is within to norm. Conclusion: Learn to live with it or buy another cam.

[Rob Lohman]

Can you post a full resolution frame on a site somewhere, Bernd?

[Bernd Binder]

I will do it next week.