View Full Version : Aliasing in 720p - XF300
Tim Polster November 19th, 2011, 02:56 PM Hello,
I am getting used to the XF300 and am very happy with the image. But I noticed this from a shot today and wanted to see if this had ever been solved or addressed.
The image has been adjusted in Photoshop to try and get the gamma correct as this is a frame from Edius and the YUV to RGB conversion always kills the image.
The lines on the track are showing horrible aliasing. This looks like a poor downconvert. I did not check this in 1080 as I do not film much at lower framerates but it makes me wonder if the 720p mode is hampered by a less than optimal hardware downconvert from 1080p?
Anyway, thanks for your input and I will contact Canon on Monday.
Pavel Sedlak November 20th, 2011, 10:07 AM Yes, XF300 has a great mode 1080/50i, 720/50p mode is very bad.
http://thebrownings.name/WHP034/pdf/WHP034-ADD50_rev1_Canon_XF300-305.pdf
Ray Pegram November 22nd, 2011, 04:30 PM Hi Tim,
So is there any update from Canon? I use 720 50p almost all the time to take advantage of the great slo-mos that can be achieved in post.
Now with this aliasing issue I may have to go back to 1080 25p
Tim Polster November 22nd, 2011, 07:56 PM I have been in contact with Canon and they are checking into it. They had me play the clip straight from the camera to my production monitor just to rule out any NLE issues.
I will keep you updated on all of the gory details!
Tim Polster December 4th, 2011, 08:47 AM A little update: I sent the original footage to Canon last week and have not heard back from them yet. I will follow up next week.
Tim Polster December 13th, 2011, 02:53 PM Still have not been contacted by a Canon tech to talk about my footage...
Tim Polster December 29th, 2011, 12:50 PM Update:
I called Canon again and finally got a higher level tech to look at my footage. They see the problem and are sending to engineering.
Please see my other post regarding reporting aliasing to Canon as they told me this issue is NOT on their radar.
Graham Bernard December 30th, 2011, 01:13 AM ....this issue is NOT on their radar.
And what is supposed to be our interpretation of that euphemism? That they need a more powerful RADAR scanner or that this is an issue of less than identifiable importance?
I'm going to the London show at Earls Court in February and more than willing to have them review their "concerns".
Luving this camera!
Grazie
Tim Polster December 30th, 2011, 11:44 AM Hello Graham,
Please talk to as many folks as you can. In speaking with the level II tech yesterday I got the impression they had never heard of 720p aliasing issues. He hinted that no reports from the call volume meant a low chance of anything being done about it.
I just does not make sense to me if the chipset is progressive how this could be introduced when downsampling to 720p. Maybe the chipset is not progressive or maybe the aliasing happens in 1080p as well. I only shot in 720p60 that day.
I would be happy to test more but to be honest, I only want to put the effort out there if Canon is willing to work to fix the problem. No point in going to great lengths only to get a "sorry" at the end of the road.
Graham Bernard December 30th, 2011, 12:29 PM No point in going to great lengths only to get a "sorry" at the end of the road.
And now it's below your RADAR. Now, don't you feel better?
G
Tim Polster December 30th, 2011, 12:56 PM Graham,
I don't quite understand your point. Please clarify.
Graham Bernard December 30th, 2011, 01:40 PM Oh, simple really.
Your resignation to what might be a phyric victory might not be worth the effort you might expend, and that Canon would also not pursue this further either. As you say, you were told it wasn't on their RADAR and as a result, my understanding, it might not now be on yours either. And my point was that to stop now would be a better use of your efforts, rather than pursuing what could be a fruitless mission.
Cheers
Grazie
Tim Polster December 30th, 2011, 02:08 PM I agree, all of the testing on a user end can not make the company take any action. I want to hope that the mission as it is will not be fruitless. I told the Canon employee that in my opinion, this situation turns into an issue of integrity for the company. They made the camera and labeled it professional. It has a large flaw, at least my camera in its present state. I asked them for a dialogue and time will tell if they are going to participate.
As far as being on my RADAR, it will remain as I mainly shoot in 720p60.
Mikko Topponen January 9th, 2012, 02:44 AM One thing that helps a lot is increasing the noise reduction. This happens before scaling and if you take it to 10 the 720p will be pretty clean.
Tim Bakland January 9th, 2012, 08:22 PM Pyrrhic Victory. You don't hear that one every day on this forum!
Tim Polster January 12th, 2012, 08:50 AM Hello Mikko,
Thanks for the suggestion. I remember reading this in the BBC writeup. I think I had the noise reduction set on "automatic" when shooting this footage. I will have to test to see how much impact this has on aliasing or how much degredation high noise reduction has on the image.
Lee Mullen May 4th, 2012, 04:10 AM Bad this on Canon. Did they EVER get back to you? Happy to take our $$ of course.
Tim Polster May 4th, 2012, 10:11 AM I have not heard back from Canon support but Luckily, I have not seen the issue again. I did film in the same scenario (high school football field with track surrounding) and could not replicate the aliasing. This is a good thing. Strange, but good!
This camera does create beautiful images!
Lee Mullen May 4th, 2012, 10:10 PM I'm looking at getting one after selling my EX1 so doing the research now. What is it like to use handheld?
Tim Polster May 4th, 2012, 10:22 PM I think it is way better than the EX-1. Although it is still kind of heavy for prolonged handheld shooting. Fits your hands well and the button layout is very nice. IS is very good as well AF if you need it.
|
|