Compatte digitali e video HD resolution; attention! 
One of the most delicious of next-generation compact is the ability to shoot movies in high definition, HD. But it is not
all that glitters is gold ... and going to read measurements
Digitalcamerainfo about it, there are some surprises.
It turns out, for example, said that the 720p from the Kodak Z812 IS - a compact of the first to adopt this format HD (1280x720, the other is the "big" 1080p) - is able to resolve about 125,000 total points resolution (the product lines lw / ph horizontally for the report format for lines in vertical consider it as the number of distinct points in the final image or frame product).
just the lowest value of 127,000 points in a small Sony H7 that had the classic "old" VGA format of 640 lines x 480 vertical lines orizzontali.E well below the excellent Canon S5 which always with a 640x480, 162,000 could solve clearly points in a single frame of video.
The Kodak Z812 from a video format 1280x720 125,000 resolve image points.
The Canon S5, a video format of 640x480, 162,000 resolve image points.
something does not ...
Fortunately, there are compacts that have a movie that is much closer to HD videocamere.La the Sony T900, for example, can not resolve more than 638,000 points, which is almost the capacity of resolution estimated by
Camcorderinfo on a good HD camcorder like the Canon HV20 by amateurs.
Sorry to find surprises like the 720p a compact race as the Panasonic LX3 that addresses 314,000 points, compared with a slim compact camera like the Canon Ixus 990 (SD970 dal'Europa out) over the 650,000 points, always starting from 720p.
must therefore pay attention to labels. How do?
addition to go and see the specialist sites, you should keep an eye on the bitrate, ie the quantity of MB for the machine to "eat" to make 1 second of the filmato.Se Mb / sec are few, the question is lecito.E 'true that the bitrate is occupied by other information such as audio (mono or stereo, range of frequency range, etc.. From this we will in the future, today we talk about resolution).
But if we think that an HD camcorder also works at 25Mb / s and beyond, it is clear that a 720p that weights 2 or 3 Mb / s can not be of the highest quality.
convention, some believe that user must have at least 5 or 6 Mb / s even with the new formats High compression like MPEG-4 .264 h, and even more for less performance formats such as AVI.
Maybe worth a bit exaggerated, but .... in the near future, it is certain that the mass of consumers will not buy more than one camera and a camera, but one device that will do both.
UPDATE 16 / 6; image points recalculated according to the formula more orthodox "lph / hx asp.rat. Lph x / v". The numbers changed a little, but not the positions of prominence / inferiority between the machines mentioned and above all does not change the fact that there are around 720p less than good from the point of view of 640x480 resolution capacity and the fact that among the 720p there are strong differences.
update: Here's a link to all digital cameras, compact and compact, with HD video on the market on July 27, 2009, the Japanese site of dc.watch.impress
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- Higher resolution images 
