Stupid technical spec of the day
Nov. 10th, 2008 10:15 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
dsrtaoA digital camcorder with a quoted 1000x digital zoom and 35x optical zoom.
Now, an optical zoom is a set of lenses that focus light like a telescope. 35x is kind of silly -- if you don't have a rock-solid tripod, the shake is going to render the image at full zoom pretty much unusable.
But. A digital zoom isn't really a zoom -- it's just blowing up the pixels that you've already got and discarding the ones around the edge. With a 2x digital zoom, you threw away 3/4 of the pixels (1/2 of the vertical, 1/2 of the horizontal). With a 35x digital zoom, you would be throwing away all but 1/1225 of the pixels. If this is a HiDef 1080P video camera, 1920x1080 original frame size, you've reduced your effective resolution to about 60,000 pixels. That's not so great. But that's not what they're quoting -- they're saying they have a 1000x digital zoom. That means they're throwing away all but 1 pixel in a million.
1920x1080 = 2073600
2 pixels left at 1000x zoom. Utterly useless.
Now, an optical zoom is a set of lenses that focus light like a telescope. 35x is kind of silly -- if you don't have a rock-solid tripod, the shake is going to render the image at full zoom pretty much unusable.
But. A digital zoom isn't really a zoom -- it's just blowing up the pixels that you've already got and discarding the ones around the edge. With a 2x digital zoom, you threw away 3/4 of the pixels (1/2 of the vertical, 1/2 of the horizontal). With a 35x digital zoom, you would be throwing away all but 1/1225 of the pixels. If this is a HiDef 1080P video camera, 1920x1080 original frame size, you've reduced your effective resolution to about 60,000 pixels. That's not so great. But that's not what they're quoting -- they're saying they have a 1000x digital zoom. That means they're throwing away all but 1 pixel in a million.
1920x1080 = 2073600
2 pixels left at 1000x zoom. Utterly useless.
(no subject)
Date: 2008-11-10 05:32 pm (UTC)(no subject)
Date: 2008-11-10 05:42 pm (UTC)(no subject)
Date: 2008-11-10 05:46 pm (UTC)Everyone's spoiled by the scifi on CSI: "There! That bloodstain! Enhance the picture 1000 times!"
(no subject)
Date: 2008-11-10 05:48 pm (UTC)All these tech claims show is that most products at a given time are quite similar and that marketing types need to find things to use to try to differentiate their's from the pack. Soap is soap.
irrelevant comment
Date: 2008-11-10 05:50 pm (UTC)Re: irrelevant comment
Date: 2008-11-10 06:29 pm (UTC)(no subject)
Date: 2008-11-10 06:30 pm (UTC)