General Canon's line-skipping(?)

S

-Sandro-

Well-known member
Hello,
Some said that line-skipping or bin pixels is the only way to handle that amount of data down to 1080p. BUT how come that Panasonic can? Have you seen videos from the hacked GH1 or the new GH2, OK the GH1 has less pixels than Canons but it's still 12MP. To my eyes videos look perfect and aliasing is practically nonexistent..and the body is CHEAP. So if they line-skip too with maybe aliasing filters how is it possible that videos from the GH1/GH2 look so clear and the resolution looks and IS like double the 5D?
I started having these thoughts when buying the t2i 2 months ago I realized that my 1080p videos practically look exactly like 720p ones and that 720p ones were unwatchable due to moiré...it's REALLY bad :(
Some suggested that they could fix it with the new canon processor but there are already rumors of a +20MP sensor (and they probably will due to the "pixels upgrade" marketing) so how are they supposed to fix this if they put even more data to downscale?
I would be very inclined to buy a FF sensor with 1080p native res only for video that would cost the same or less while using my lenses and keeping my t2i for stills. I don't see why it should cost more or the same even! If they made a product for video only, with similar sensor but with -only- 1080p res why would it cost the same or more than a DSRL with 18-20MP sensor and that does pictures too?

Anyway...does anyone know what Panasonic does with the GH1?
 
* I'm not so sure panasonic does line-skipping; in my eyes, they either use data from the whole sensor, or skip sensors in a pattern that's not as simplistic as "line-skipping"; maybe I'm wrong and they do skip full lines of sensors, but it doesn't seem so

* because of how a bayer-pattern sensor works, you don't want a 1080p native res sensor: images won't come out looking sharp; you want higher-res and then a scaling-down algorithm
 
Can you explain me why a 1080p native sensor won't be sharp? Anyway I'm still curious to know why everyone is discussing about every company that is not capable of handling data to downscale yet while Panasonic IS doing it
 
We don't know how Panasonic does what they do. For that matter, we also don't know how Canon does what they do. Sure, there are people who will proclaim authoritatively that Canon does this, or Panasonic does that, but the truth of the matter is they do not know. Only the engineers at Canon and Panasonic know how their chips work. Anyone postulating on line-skipping or pixel binning or whatever, is speculating.

Why a 1080p native sensor wouldn't be sharp? If it's a Bayer pattern, then yeah, it wouldn't be very sharp. You lose about 30% of your nominal resolution when going through the de-mosaic process to turn a monochrome sensor (and all sensors are monochrome) into a color image. If you're using a single chip and a Bayer pattern, then you have to demosaic it to take the individual red, green, and blue-sensing pixels and synthesize a full-color image out of them. And the resulting resolution loss is typically on the order of about 30%, so you'd want a chip that's about 30% higher-res than 1080p, if you want to end up with a good sharp 1080p final result.
 
-Sandro- said:
Anyway I'm still curious to know why everyone is discussing about every company that is not capable of handling data to downscale yet while Panasonic IS doing it
Click to expand...

Umm because this is the Canon sub forum in which most talk about Canon ideas, issues and workflows... Try the GH1 subforum where you can probably find a good many threads and discussions on the matter.

I do agree that however the GH1 is doing what they are doing for overall aliasing... it's much better. Specially with the hack, it's a pretty swell camera :love4:
 
For what it's worth, I agree that the Panasonic m4/3 cameras do look sharper than my 7D.. I think it has to do with the aspect ratios of going between a 4/3 sensor and an aps-c sensor (cropping, line-skipping, compression, etc..) but as Barry pointed out.. I obviously don't know for sure. Just putting out my opinion on the matter! ;)
 
hey :) I don't mean here, but in general on the Internet. Panasonic just demonstrates that it is possible to do and the others are just behind. That's my opinion.

Yes the hacked GH1 destroys even the 5D hands down! I would be ashamed if I was Canon :D and it's just £400 body only
 
non hacked gh1 is not much better than 7d,i wonder how hacked 7d/5d/2ti would look like with higher bitrate
 
bwwd said:
non hacked gh1 is not much better than 7d,i wonder how hacked 7d/5d/2ti would look like with higher bitrate
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GH1 with C-settings has lower aggregate bitrate than 7d/5d/550d. I don't think Canon would gain much from raised bitrate w/o doing something about rescaling algorithm. Canon H264 implementation is quite rudimentary and needs high bitrate to mask the lack of Cabac, B-frames and mess that moire creates.
 
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