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-   (MPG4) Sanyo Xacti (all models) (https://www.dvinfo.net/forum/mpg4-sanyo-xacti-all-models/)
-   -   Concern about the HD 16:9 (https://www.dvinfo.net/forum/mpg4-sanyo-xacti-all-models/63230-concern-about-hd-16-9-a.html)

Graham Jones March 19th, 2006 02:16 PM

Concern about the HD 16:9
 
The OLED screen isn't 16:9 so naturally has black masking at the top and bottom when you're shooting in HD and 16:9.

However, the masking is semi-transparent, and one can actually see picture through it.

Does this indicate the HD / 16:9 mode is a cropped image?

If so, what ramifications might this have?

Chris Taylor April 7th, 2006 10:36 PM

cropped is fine and is likely exactly what its doing (IE take some stillsnote they are not in 16:9)

what IS important is does it "stretch" to make the 16:9 after it crops.

I think no. I think its just "using" the 1280x720 pixels of the 5 million it has to make the HD image in which case this is just fine.

Chris Taylor
http://www.nerys.com/

Graham Jones April 8th, 2006 06:18 AM

That's reassuring. I just remembered the whole 16:9 vs. True 16:9 debate, where 16:9 cropping meant res loss...

Bo Lorentzen April 9th, 2006 03:56 PM

Graham,

Yup, I think its using just the real-estate required for the 16:9 no resolution loss from that....

But just how its done is still a little shady I suspect.. as there clearly is a true 5 megapix chip in the camera, this means about 2500 pixel wide source image, which is then reworked to the 1280px this "should" bring a lot of resolution with it by default, however strangely the camcorderinfo review suggest that the actual resolving power is not more than about 25% better than a good regular miniDV cam... To my confused mind this is pretty strange, the 5 meg shots I have checked clearly have more resolving power than this... and the HD comes from the same chip.. so there is no bad optical path involved...

They rated the HD1 sharpness at "21" and the Optura600 at "17" so there IS clearly a significant increase... also when shooting regular video it was rated very sharp... Honestly I do not really understand their wording... saying resolving 460 lines across, does that mean resolving 460 vertical lines..? Not that it matters really... as I said before.. IM happy with what I see on my TV. (smile)


Bo

www.bophoto.com/HDV/video

Graham Jones April 10th, 2006 01:02 AM

I am used to being disappointed by the stills from a video camera, because it's usually just arbitrary frame grabbing, or by the video from a stills camera - often no more than a recording of the LCD monitor feed.

I think of the HD1 as a dedicated stills camera and a dedicated video camera.

But camcorderinfo suspect the Xacti is a still camera posing as a video camera.

All I would say is, ten years from now the two devices will not be as separated as they are in today's market.

Chris Taylor April 10th, 2006 03:14 AM

10 years from now I bet we will have 5 10 15 MEGAPIXEL Video at which time a frame grab will print a poster :-)

I cant wait till we have affordable 30mp cameras !

Hey I can dream :-)

Graham Jones April 10th, 2006 03:40 AM

Yes, frame grabbing is okay in post - but video cameras that do it live, under the pretence of taking stills, will tend to make poor stills because good frames and good stills are not the same thing...

Chris Taylor April 10th, 2006 10:20 AM

well what would be nice if if when it grabbed the frames it grabbed it at the INSTANT that you pressed the buton and also grabed every other frame for 5 frames before and after so later in post you could "pick" the best grab.

I do with it could capture a 5m still without pausing the video. that would make this camera about as close to perfect as is possible :-)

Chris Taylor
http://www.nerys.com/

Graham Jones April 10th, 2006 10:43 AM

That would be nice - but the reason the stills are proper stills and not just framegrabs is because it doesn't do this, it reacts to pressing more like a regular digi still cam!

Graham Jones May 16th, 2006 05:34 AM

This 16:9 cropping is also discussed in this thread - suggestion that the sensor isn't fully used for 16:9 HD shooting

http://www.dvinfo.net/conf/showthrea...d=1#post483132


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