You are correct if you just throw away one field and duplicate the remaining one. However, in some applications there are algorithms to minimize this effect by interpolating between the two fields and depending on the quality of the algorithm used, you may lose less than 50%, but you never end up with 100%. Often deinterlacing leads to noticeably softer images.

You're right, Mike. I'm sold! Going to keep my Z1. Thanks to everybody for taking the time to set me right :-)

What a board... within ten minutes of my originating this thread I had all the answers I needed. Simply amazing.

Thanks everybody.

James,

If you weren't convinced, I was going to do a search to find an example Douglas Spotted Eagle uses of SD vs. HDV-down-converted-to-SD clips. They involve a digital push-in; the SD footage was pixelated; the HDV-to-SD footage was only very slightly pixelated. This is because there are over 300,000 pixels in SD-originated footage and around 1.5 million pixels in 1080i HDV-originated footage.

Glad you're here!

heath

See my illustrations on this page:

http://www.dvinfo.net/canonxlh1/articles/article06.php

They pretty much explain PAR at a glance.

Thanks, Chris. I'll link to that from now on.

hwm

Spot's book is so much better because it goes into wonderful detail, but my illustrations are more... immediate.

Ha ha, of course. Hey Chris, maybe we should move this to General HDV discussion or the Z1 discussion threads?

heath

Heath, a slight technical correction here. The F350 is the more expensive of the two and the body only price is just under $25K, the F330 is the $15K body.

Also, the sensors on the Z1 are only 960 horizontal and get pixel shifted to 1440 which would then be elongated with PAR to form a 1920X1080 image.

The sensors on the F330/F350 are native 1440 horizontal and no pixel shifting is involved, only the standard PAR correction to form 1920X1080.

When you get up in the really big dollar cameras such as the HDC-1500, you get native 1920 horizontal sensors and true 60P capability. But then you're looking at $90K for just the body.

Nonetheless, the Z1 does produce beautiful video and I'm glad James has decided to keep his camera.

-gb-

So where does that leave the 720p cams? A friend of mine has a JVC that records 720p. How do they go from 720 lines to 1920 x 1080?

They don't! But, it is progressive at 720p. That is one of the two main current platforms. You have 720 which is always progressive, as far as I know, and you have 1080 which can be progressive or interlaced.


Mike

Oh really? So then *cough cough* his cam is lower resolution than mine? The 720p cams have *cough cough* lower resolutoin than the Z1's?

720p is very popular, as it is able to shot motion better. It does not suffer from interlacing artifacts, like 1080i would. 1080p would not suffer from them either, but is newer and not in as many cameras. When it is, 720p will probably fade into the sunset, at least for TV I think. It will still be fine for movies and transfer to film.

As far as higher resolution formats, RED etc. they are mostly for film replacement, as 1080i or 1080p will be all that be be displayed on TV. And, that will remain the new standard for many many years to come. It is just much too expensive for goverments to change it again soon. Thank goodness for that too!


Mike

Yes, but don't cough to loudly, as his is progressive and yours is interlaced! One frame of yours contains only half of the info, and it would take two of yours for a complete frame, thus interlacing, and its artifacts. His captures a full frame each time, and that has advantages. When you get 1080p then you can cough, loudly!

Mike

Should you not have said: One FIELD of yours contains only half of the info, and it would take TWO FIELDS of yours for a complete frame.....

They don't, James. When recording in the 720P format, the horizontal resolution is 1280 as opposed to 1920. That's the 16:9 ratio.

1280x720P vs. 1920X1080I. As you can tell, it's all about compromise. You can have a progressive image at a lower resolution or an interlaced image at higher resolution.

Of course you can turn a 1280X720 image into 1920X1080 but it's going to be an uprezzed image and will theoretically look inferior to a native 1920X1080 image. I say theoretically because as we've seen around here numerous (get it - numerous) times, numbers don't tell the whole story.

All in all, I'd say we have some darn nice tools for image creation available these days.

-gb-