New cameras or stick with PDX10?

Boyd Ostroff · February 14th, 2004, 09:38 AM

All DV cameras use an image size of 720 x 480, but that has no relation to an individual camera's resolution, which has more to do with the optics and electronics. Actually the DV codec itself is limited to around 530 horizontal lines, so no camera is going to get much better than this (but I suspect that many are comparable). Take a look at some PDX-10 still photos from the megapixel chips and compare to still DV frames. Right away you'll see the trade-offs made when compressing 30 pictures per second on the fly with DV.

A search should give you more background on DV and resolution; here's one thread with a lot of information.

Jim J. Donaldson · February 14th, 2004, 10:39 AM

Hare are a few more resources that describe line of horz. resolution and how the different video formats compare.

"A standard way of specifying the clarity of a video image is by its lines of horizontal resolution. By this standard, the DV format really stands out. It has 500 lines, about twice the resolution of VHS and 8mm video and 25% better than S-VHS or Hi-8."

http://www.shortcourses.com/video/chapter05.htm

"Standard NTSC live broadcast TV has a horizontal resolution of 330 lines, broadcasts from video tape have about 300, and laserdisc has 420. Super-VHS and Hi-8 also have 420 lines of resolution, although the picture is not quite as good as laserdisc, illustrating that there are more factors than just resolution that go into making a video image."

http://www.hometheaterhifi.com/volume_1_1/v1n1vcrs.html

Marco Leavitt · February 14th, 2004, 03:59 PM

Man that really blows! I know resolution isn't everything, but it's a lot.

Dave Haynie · March 9th, 2004, 04:20 PM

The whole "lines of resolution" comes from optics, ages ago. Back then, and still in still photography, they speak of line-pair, not lines: obviously, for every back line, there's a corresponding white one, or you wouldn't see lines at all.

Anyway, the area of measure is traditionally a real circle inscribed over your focal plane. Before there was any distinction in the means of recording horizontal or vertical imagery, this wasn't necessarily recorded as lines of horizontal or vertical resolution, just lines of resolution.

When video came along, the horizontal dimension was the interesting one. You pretty much could guarantee a lens that wasn't at issue, and in the vertical, the resolution was basically digital (eg, your 484 or 576 or whatever potentially visible scan lines). But in the horizontal, you're analog.

So basically, now converting that to digital, you have a circle still based on your vertical resolution: 480 pixels in DV/NTSC. And from that, you have a horizontal circle extent based on your horizontal resolution and aspect ration. So measured at 4:3 and 720 pixels, the limit is something just below 540 lines. In 16:9, with precisely the same optical characteristics and resolution, your limit is something just below 405 lines.

In other words, if your camcorder does 530 lines, in practical terms, that's as good as it gets (you'll have to judge, at the edges of that circle, where a line really begins, to decide if you believe this is slightly off the theoretical max, or in fact nailing the theoretical max).

Boyd Ostroff · March 9th, 2004, 06:29 PM

Some great info Dave, thanks! If you're really interested in seeing all this with your own eyes, there's a pretty simple test. Download the EIA-1956 test pattern from John Beale's website, resize in Photoshop to 720x480 and drop it into your NLE as a still image. Now on your NTSC monitor you should be seeing the actual max resolution that DV can give you since no optics or CCD's are involved. If you look at the numbers next to the converging horizontal and vertical lines you can graphically see the resolution. It's interesting to compare the image on your NTSC monitor to the 720x480 photoshop image displayed on your computer monitor. You willl see all the telltale DV artifacts that aren't present in the JPEG.

Then if you want to see what your camera is capable of, print up one of the higher res versions of the chart, shoot it, capture it, and compare...

March 9th, 2004, 04:20 PM	#19
Dave Haynie Regular Crew Join Date: Mar 2004 Location: Upper Pittsgrove, NJ Posts: 95	A little resolution history The whole "lines of resolution" comes from optics, ages ago. Back then, and still in still photography, they speak of line-pair, not lines: obviously, for every back line, there's a corresponding white one, or you wouldn't see lines at all. Anyway, the area of measure is traditionally a real circle inscribed over your focal plane. Before there was any distinction in the means of recording horizontal or vertical imagery, this wasn't necessarily recorded as lines of horizontal or vertical resolution, just lines of resolution. When video came along, the horizontal dimension was the interesting one. You pretty much could guarantee a lens that wasn't at issue, and in the vertical, the resolution was basically digital (eg, your 484 or 576 or whatever potentially visible scan lines). But in the horizontal, you're analog. So basically, now converting that to digital, you have a circle still based on your vertical resolution: 480 pixels in DV/NTSC. And from that, you have a horizontal circle extent based on your horizontal resolution and aspect ration. So measured at 4:3 and 720 pixels, the limit is something just below 540 lines. In 16:9, with precisely the same optical characteristics and resolution, your limit is something just below 405 lines. In other words, if your camcorder does 530 lines, in practical terms, that's as good as it gets (you'll have to judge, at the edges of that circle, where a line really begins, to decide if you believe this is slightly off the theoretical max, or in fact nailing the theoretical max). __________________ --Dave

February 14th, 2004, 09:38 AM	#16
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	All DV cameras use an image size of 720 x 480, but that has no relation to an individual camera's resolution, which has more to do with the optics and electronics. Actually the DV codec itself is limited to around 530 horizontal lines, so no camera is going to get much better than this (but I suspect that many are comparable). Take a look at some PDX-10 still photos from the megapixel chips and compare to still DV frames. Right away you'll see the trade-offs made when compressing 30 pictures per second on the fly with DV. A search should give you more background on DV and resolution; here's one thread with a lot of information.

February 14th, 2004, 10:39 AM	#17
Jim J. Donaldson New Boot Join Date: Nov 2003 Location: Findlay, Ohio Posts: 21	Hare are a few more resources that describe line of horz. resolution and how the different video formats compare. "A standard way of specifying the clarity of a video image is by its lines of horizontal resolution. By this standard, the DV format really stands out. It has 500 lines, about twice the resolution of VHS and 8mm video and 25% better than S-VHS or Hi-8." http://www.shortcourses.com/video/chapter05.htm "Standard NTSC live broadcast TV has a horizontal resolution of 330 lines, broadcasts from video tape have about 300, and laserdisc has 420. Super-VHS and Hi-8 also have 420 lines of resolution, although the picture is not quite as good as laserdisc, illustrating that there are more factors than just resolution that go into making a video image." http://www.hometheaterhifi.com/volume_1_1/v1n1vcrs.html

February 14th, 2004, 03:59 PM	#18
Marco Leavitt Inner Circle Join Date: Jul 2002 Location: Albany, NY 12210 Posts: 2,652	Man that really blows! I know resolution isn't everything, but it's a lot.

March 9th, 2004, 06:29 PM	#20
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Some great info Dave, thanks! If you're really interested in seeing all this with your own eyes, there's a pretty simple test. Download the EIA-1956 test pattern from John Beale's website, resize in Photoshop to 720x480 and drop it into your NLE as a still image. Now on your NTSC monitor you should be seeing the actual max resolution that DV can give you since no optics or CCD's are involved. If you look at the numbers next to the converging horizontal and vertical lines you can graphically see the resolution. It's interesting to compare the image on your NTSC monitor to the 720x480 photoshop image displayed on your computer monitor. You willl see all the telltale DV artifacts that aren't present in the JPEG. Then if you want to see what your camera is capable of, print up one of the higher res versions of the chart, shoot it, capture it, and compare...