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leroyvanhee Dec 19, 2007 6:42 PM

The one feature thatinterested meon the Z812 was it's capability to produce 720P videos. Most hi-def camcordersproduce only interlaced video and most hi-def monitors show only progressive video.As a result,there's a problem with the compatability of these devices that causes motion to be blurred. (I thought that capturing action/motion was the whole point of video vs. still photos. )

720P video should captureaction that's compatable with computers and hi-def televison screens, and it does. However, I find the quality of the 720P video produced by the Z812 disappointing. It is blurry, appearing to be out of focus. To illustrate my point I've posted some examples:

1. A single frame of a Z812 video cropped to eliminatesome sky:

2. A cropped section of a Z812 still photo showing actual pixels:

3. The whole still photo reduced to fit the screen:

None of the photos were edited except for cropping (1 & 2) and resizing (3).

ac.smith Dec 19, 2007 7:53 PM

I'm not sure what you saying here but what you doing is comparing an 8.1 MP (3298x2472) image against a 1.2 MP (1280x720) image (with two different compression algorithms, jpg and mpeg4 as well.)

leroyvanhee Dec 19, 2007 8:41 PM

The reason for the cropped image (2) is to show the video frame and a still image at the same number of pixels per inch. It's an equalcomparison.

So you're saying that MPG4 is supposed to be blurry? I'm still disappointed.

ac.smith Dec 19, 2007 9:18 PM

I'm saying that a 1.2 MP image, by definition is lower resolution than an 8.1 MP image. You compared one frame out of video to a still photo. There is no comparison.

A couple of other physiological and technical factors come into play as well. Our eye/mind system is less critical on sharpness when viewing a motion image and the design of our movie/video systems have taken advantage of that from the beginning of motion pictures. Additionally the typical computer monitor today still out does the latest HD TVs in resolution so it's not surprising that an image that's fine on an HD TV doesn't look as good on a decent computer/monitor system. I think you alluded to that in your original post.

style="BACKGROUND-COLOR: #000000"You might want to download the HD sample video in Steve's review of the Z1275 for comparison to your videos.

leroyvanhee Dec 20, 2007 9:20 AM

I tried to match the quality of the Z812 video frame andmy result is posted here:

To create this image I first reduced the size of the still photo to 220p then I resized the 220p image to 720p. That is, I started with a Low-Def photo and digitally zoomed it to Hi-Def. Is the result really Hi-Def?

ac.smith Dec 20, 2007 5:25 PM

Can you download Steve's HD sample in the Z1275 review and then capture a frame? That's the only way your going to get something that you can compare. No amount of manipulation of the Z812's still image will give a "should be equal" image to compare to a still frame capture. Everytime you manipulate unknown and uncontrolled variables are introduced.

Compare video capture to video capture. The variables between the Z812 and the Z1275 are sensor and lens at that point. I suggest that particular sample because it's the only proper done HD sample I know of on a reputable test sight.

leroyvanhee Dec 22, 2007 1:00 PM

I don't thinkcomparing a frame from another Kodak 'HD' video is avalid test. They probably use the same process to createboth outputs.

I do have a frame from another 'HD' camcorder. It's not a high-quality frame either but it suffers from a different set of problems. It is a cropped image (1:1 zoom) from a Canon HV10. The Canon produces video in 1080i format on a miniDV tape. The quality problems are: 1) it is interlaced so the even number lines are captured 1/60th of a second from the odd numbered lines (You can see a double image in the green flag), and 2)it isexcessively compressed tofit on the miniDV tape. They want the same bit-rate as a standard-definition video so a standard 60 min tape will record 60 min of HD video. You can see the compression artifacts around the car frame and the number 4 on the car. These are problems that I hoped the Z812 wouldovercomebecause it produces progressive video (the whole frame is captured at the same instant) and there is no need toexcessively conpress the frames. Seemy example at:

I'm disappointed.

leroyvanhee Dec 23, 2007 9:44 AM

OK...I was wrong. Taking a frame from Steve's Review was a good idea. The sample is quite good. I would be pleased if mine were as good. Now I need to find out why they aren't. See frame from Steve's Review:

leroyvanhee Dec 27, 2007 3:49 PM

Here's another test. I tried to make it as favorable to video as possible. Used ambient light (no flash) anda tripod from about 5ft. with zoom at wide angle end.

First photo is a still set to the smallest size (1.2 mpixels) and cropped:

The second image is a video frame, also cropped:

The biggest difference seems to be more noise on the video frame.

leroyvanhee Dec 28, 2007 1:47 PM

This article by Lester J. Kozlowski: that CCD sensors have reached their limits for speed and signal-to-noise ratio. The successor technology seems to be CMOS. The Canon HV10 mentioned earlier in this thread uses a CMOS sensor as do many of Canon's high-end DSLRs. (I have seen no unusual noise problems with my HV10.) It's more expensive than the Z812, but according to DALSA's not necessarily the case.

You and I can probably look forward to more CMOS-HD video cameras in the near future. In the mean time, it looks like we'll need to find ways to crutch our Z812 videos so they look more like to one documented in Steve's Review. This probably means we need to assure there's plenty of light on the front of our subjects.

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