Many thanks, A.J., your detailed explanation is much appreciated. Is there are proper term for this issue (and if not, should we come up with one of our own)? Since it has obviously been mislabeled (somewhat vehemently by some people) as "chromatic abberation," it would be nice if we could properly educate those who incorrectly assume it as such. To me, reduced chroma color bandwidth is an accurate description of the cause, but not the symptom itself.

Chris,

from what i've seen so far, from the res charts, the manual lense looks a lot more "solid".

There is almost no CA, and the res is as good as the stock lense.

I think the 20X lense does create some CA.

The 3X is also a lot cleaner than the 20X to my eyes.

A.J.,

Thanks for your excellent analysis. All this makes now a lot of sense.

Yes, this is what I said earlier in this thread; When I take the signal from the HD-SDI port, the effect is less visible, which is why I had difficulties to agree with others that the effect is caused only by the lens.

This is precisely the case. Yesterday there was first high contrast across the transition but as soon as the sun turned more on the left the contrast got lower and the effect diminished.

Now, that the issue is understood makes it clear how the custom presets can be exploited to remove the effect -and this vindicates A.J's hypothesis; Instead of setting sharpness I made a new experiment with Noise reduction 2, which I set to "high". The frames are here

www.luontovideo.net/Neutral.tif
www.luontovideo.net/NoiseReduction2.tif

and the green border between the wall and stair way is less noticeable. (I also use gamma set to Cine1, which I've found to help with the border effect. The reason is clear: contrast becomes lower.)

All this makes me now to suspect that the EF-adapter is a kind of low pass filter which acts bit like Noise reduction 2 softening the image. This explained i) why the images produced with EF-lenses seem to have less contrast as if they were slightly grayish compared to the standard 20x lens, ii) why people report "there is less CA with EF-lenses" and also iii) explained why Canon say the EF-lenses are not HD-compatible. The visual impression of XL H1 + EF lenses is though still very pleasing. The moral is, judging images based only on visual examination is very difficult and easily leads to misconclusions. Still, would like to emphasize, the final conclusion is to be made.

Chris,

I'd say we should refer to Lauri's wall problem as the "chroma undersampling effect". Note that I'm using "effect" rather than "problem" because it is there intentionally as part of the design and there are a couple of ways (that we know of at this point) to get around it: increase sampling to 4:2:2 (use SDI), turn on noise reduction, lower contrast (either through lighting or gamma) try to keep strong verticals out of the composition, try to avoid transitions with the bright side on the right...

Or we could call it the "Lauri's wall effect".

Whatever we decide to call it I don't think that is the end of the story because I don't think this phenomenon covers all the artifacts that people have been talking about in this thread. The fact that this particular situation was not caused by chromatic aberration does not mean that the XL-H1 doesn't exhibit some chromatic aberration with the stock lens. It definitely does. Also aliasing, DCT tiling, haloing, and all the other things I mentioned in an earlier post are still being called chromatic aberration by some.

A.J.

Adjusting the R-G, G-R, etc. entries of the color matrix help as well. After shooting the www.luontovideo.net/Hawk owl.tif footage, I spent a lot of time adjusting the entries of the color matrix, and after that have not seen the purple borders again. Also the green ones do not appear as often as they used to.

My background is in scientific research, and think it's never a good idea to name something after somebodies name.

Lauri,

The suggestion that we name it after your wall wasn't entirely serious but your comment got me thinking about the names of scientists whose work had some bearing on this problem/phenomenon: Newton (drew the first color wheel), Abbe (quantized the dispersive properties of glass which are responsible for CA), Airy (first Astronomer Royal after whom the form of an ideal lens's image of a point is named), Bessel (for the mathematical function which describes the Airy Pattern), Shannon (whose sampling theorem makes digital video possible), Seidel (who came up with a unified way of describing CA, spherical abberation, coma....) and lots more.

There certainly has been a lively response to this concern about the "stock" lens.. some well informed, some bashing, some defensive...

When I first got my H1 last December I tested it with the 20x and the 16x and preferred the 16x primarily for handling reasons. As I wrote then, I found the 20x sluggish and unresponsive and particularly didn't/don't like the OIS. That was, and still is, my opinion.. I sold the 16x with my XL2, but have just ordered another one, again, primarily because of handling.

But, back to the 20x. The fact is that some really nice images have already been made with this lens (some by me, if I do say so myself).. Overall, I'm not as displeased about CA.. and I do believe that much of what is being attributed to the lens is endemic of HDV and 1/3" chips... So, where does that leave us?

In my case, shooting documentaries, mostely handheld, a small amount of CA, or whatever the hell it is, is not really noticeable at all.. For others, especially those who work w/ green screen or want to shoot pristine nature footage at the long end of the lens, it will be a problem..

I remember the American Cinematographer story over 35 years ago about the production of LAWRENCE OF ARABIA - in shooting that film they deliberately chose lenses with chromatic abberations because they wanted the effect of shooting through hot desert atmosphere - and it's a "look" that has been immulated in many non-desert films since.. Pick the tool for the job.

I'm not excusing Canon for the 20x, I too wish there was another HD lens available for this excellent camera. I'm just saying that used in the right circumstances this little box is a pretty good deal for $9000.

Here here, Steven.

and don't forget Murphy.

Murphy is almighty, but don't forget Bayer's pattern and Nyquist's limit.

Here's how I knocked down a burning blue ring of fire with a simple custom preset:

http://www.dvinfo.net/conf/showthread.php?t=72218