720 vs 1080 for analogue SD output

720 vs 1080 for SD output
(Created 08 April 2008: Updated 08 April 2008)
By Guy Barwood - Glass Eye View
www.xdcamexinfo.com
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The Background:

The EX1/3 cops a lot of flack over its lack or native SD acquisition abilities & missing DV output (rightly so), but it also takes a wallop over the quality of its analogue output quality which is just as much a concern to many users who use analogue feed for things like live sports and concert mixing etc

So the question begs, if you are shooting for analogue SD output, what mode should you shoot in, 1080i or 720p? Below you will find some very simple comparison images. To me it clearly shows that to get the best quality SD interlaced output you need to be in 720 (50 or 60p) if you.

These images were taken from a Sony Bravia 52" Full HD LCD with a Nikon D3 and are 100% crops of the same/similar component of the image. Sorry the camera was not even on a tripod (was sitting on the floor) so there is some variance in framing etc but the difference is clear enough to not need anything scientific to show. No need to compare component vs composite etc. Just compare the first two images to each other, and the last two too each other.

The Images

Composite from 1080i
Composite from 1080 50i HQ mode

Composite from 720 50p

Composite from 720 50p HQ mode

Compoonent from 1080i

Component from 1080 50i HQ mode

Component from 720 50p

Compoennt from 720 50p HQ mode

Summary:

To me it is pretty clear, you shoot in 720 50 or 60p if you are using the analogue output. I don't have SD-SDI hardware to compare but my gut feeling says the results would be similar. It's a shame because if you want to shoot a HD master to card as well as use the analogue out, you have to accept lower quality SD out & shoot in 1080i or higher quality SD out and shoot in 720p.

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