Aliasing

I guess for those who are just interested in using this camera for its cinematic capabilities (not for stills) that could be a great compromise. I hope someday someone could test this out.
 
Barry, The question does beg to be answered; why do manufactures not make a Optical Low Pass Filters that can be engaged for video and disengaged for stills. I am sure to do this is much more difficult than it seems, but will someone some day solve this riddle?
 
Never discussed on these forums is the problems 5D footage creates, due to its aliasing, when heavily re-compressed for digital broadcast. if you think it looks soft on your timeline, you are in for an extremely unpleasant surprise if you ever see your work on TV.
 
Robert Ruffo said:
Never discussed on these forums is the problems 5D footage creates, due to its aliasing, when heavily re-compressed for digital broadcast. if you think it looks soft on your timeline, you are in for an extremely unpleasant surprise if you ever see your work on TV.
Click to expand...

Not specifically sure what you are referring to. Aliasing is a seperate issue than re-compression. Most of the time aliased footage looks too sharp on the timeline. If it looks too soft, aliasing is generally not an issue. Are you speaking about the compensation people make to avoid aliasing by softening it?
 
i agree with yoclay...
saw the music video for "kings and queens" by 30 Seconds to Mars a few times on Palladia(HD music channel, for those not familiar), and while it was shot primarily on the 7d(not the 5d, which is what this conversation is about now), i saw nothing but superb imagery. take it for what it's worth...it looked fantastic on TV. i'd think the 5d would hold up nicely. i kjnow, only one example though. i also don't ever watch "tv" on the internet. (i'm not assumiing that any of you do)...it just never looks the same.
 
Barry,

How does the aliasing on HD-SLRs compare to high-end consumer camcorders like the Panasonic HDC-TM700?
 
Haven't used a TM700 so I don't know for sure. But typically the aliasing on a camcorder is much less, because the OLPF is tuned for the sensor appropriately.
 
Just to add my euro cents

I think the aliasing issue is more to do with the line skipping the canons use rather than OLPF. Whilst the OLPF does have an effect it's nowhere near as aggressive as the skipping. Line skipping is like looking through venetian blinds, giant horizontal chunks of the image simply isn't being recorded.

I have an LX3 next to me, 720p and i don't have anywhere near like the artefacts as the canons. Yes, i can see moireing in places if i look for it, and that *is* down to the OLPF but if the canons performed like the LX3 in this regard i think most people would find them much more acceptable.

I'm looking forward to the new sony alphas and see what they do in that regard.

cheers
paul
 
Hi Barry or anyone else who can help,

Just joined this forum today. I have a question regarding the Panasonic TM700 (I'm a beginner with a camcorder).

I take the video in default (IA) mode...the camera does everything.
I download with Panasonic's HD Writer software to my hard drive.
I view the video and see shimmering edges (marching ants) on things like tree limbs, car door edges, etc.
I also see the same edge effects in the latest PowerDirector software.
I don't know if this is aliasing of some sort or called something else.
Not all things in video have shimmering...just certain edges.

Any suggestions as to what they are and how to fix would be greatly asppreciated.

Thanks,

Nick
 
Hi Barry or anyone else who can help,

Just joined this forum today. I have a question regarding the Panasonic TM700 (I'm a beginner with a camcorder).

I take the video in default (IA) mode...the camera does everything.
I download with Panasonic's HD Writer software to my hard drive.
I view the video and see shimmering edges (marching ants) on things like tree limbs, car door edges, etc.
I also see the same edge effects in the latest PowerDirector software.
I don't know if this is aliasing of some sort or called something else.
Not all things in video have shimmering...just certain edges.

Any suggestions as to what they are and how to fix would be greatly asppreciated.

Thanks,

Nick​
 
paulcurtis said:
Just to add my euro cents

I think the aliasing issue is more to do with the line skipping the canons use rather than OLPF. Whilst the OLPF does have an effect it's nowhere near as aggressive as the skipping. Line skipping is like looking through venetian blinds, giant horizontal chunks of the image simply isn't being recorded.

I have an LX3 next to me, 720p and i don't have anywhere near like the artefacts as the canons. Yes, i can see moireing in places if i look for it, and that *is* down to the OLPF but if the canons performed like the LX3 in this regard i think most people would find them much more acceptable.

I'm looking forward to the new sony alphas and see what they do in that regard.

cheers
paul
Click to expand...

The Canons do not line skip. They use pixel binning. Every pixel is is used.
 
^ as above - this is why the GH1 looks a little better in the res charts. Some more blarb to back this up from the EOSHD wiki:

For video, the 7D sensor has a further curtailing of advantage, because despite being larger the resolution of the sensor is 18MP compared to 12MP on the GH1's, so pixel pitch is actually similar. Furthermore, whilst the GH1 uses pixel binning to downscale the image, the 5D Mark II and 7D line-skip over the sensor to produce an image containing more aliasing and moire than if a pixel binning method was used. The ideal method would be similar to that used in Photoshop, whereby bicubic algorithms are used and pixel binning occurs in a less crude way. But current generations of image processing chips in portable electronic devices are not yet high-performance / power-economical enough at once, to handle such intensive work at over 24fps.
(Source: EOSHD.com)
From the DXOMark article, GH1 versus 7D:

The gh2's "teleconverter" mode sounds very interesting and could potentially end these aliasing/moire nasties, here

Sorry to sound like a panasonic fan-boy, just stuff i found doing my research!
 
Excellent piece on Aliasing... made sense even to me. :)

Excellent piece on Aliasing... made sense even to me. :)

Well written piece.

Made sense even to me.

Will scan the thread in search of some solutions or compromises in the form of filters or throwing the frame a little out of focus.

Thank you. :)
 
Can someone explain me how it is possible that the DSLR's image has a lot of detail and is sharp, but that it is actually rendered wrong? In most shots you dont see aliasing but according to this article it is still there cause it's responsible for a lot of the detail... How it does that?
And is it really so bad if you avoid certain situations?
 
I'd like to ask about getting rid of moire. One of suggestions in the article claims that unfocusing area with this effect could be helpful. I'm wondering how effective this solution could be (Have anyone seen some tests somewhere on the internet, or have anyone personal experience with solving these problem?).
Or are there any other "methods" (which aren't included in the article) which can lead to clear image without distracting artifacts? (and eventually how effective/expensive they are).
 
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