Aliasing/twittering EX1

[Don Greening]

Olly, have you tried adjusting the detail setting down to minus 20 or minus 25? I think minus 25 effectively reduces the detail setting to nothing without actually turning it off and greying out other settings such as aperture correction, etc. The edge detail and detail frequency settings that Sony dials in at the factory are excessive. There does seem to be a correlation between EX line twitter and how much edge detail the camera is using. Are you noticing this more with your SD down converts or when watching the native EX files?

– Don

[Olly Lawer]

Thanks for your reply.

I have only just purchased the EX1, so am doing some SD down converts now…and having a few heart stopping moments reading threads (https://www.dvinfo.net/conf/sony-xdcam-ex-cinealta/116196-how-your-ex1-sd-dvds-looking-3.html) that say you cannot get good looking XDCAM down converts to SD…surely this cannot be true?

I am using this guide to down convert to SD (https://www.kenstone.net/fcp_homepage/ex1_sd_output_young.html) although the image has now been made into a 4:3 instead of 16:9, so has squashed the image, even though this isn’t what I selected.

Have you managed to get acceptable SD DVDs from the EX1 footage, if so how?

I will do as you suggested and lower the detail – does this have a big affect on the image quality also?

[Don Greening]

[Olly Lawer] “does this have a big affect on the image quality also? “

No. It actually makes the picture look more organic and natural. Less like video and more film-like. Here’s a recent discussion on successfully down converting from HD to SD. At least for users of Final Cut Pro:

https://forums.creativecow.net/thread/142/862811

– Don

[Olly Lawer]

Thanks.

I will have a look through this. Just to set my mind at rest, have you managed to get good looking SD DVDs from the EX1?

[Don Greening]

[Olly Lawer] “Just to set my mind at rest, have you managed to get good looking SD DVDs from the EX1? “

I continue to experiment but for the most part I’m satisfied with the SD results.

– Don

[Olly Lawer]

Not hugely reassuring.

Better then other Cams like Z1?

Would you say for someone that will need to produce SD DVDs the EX! is not a good option?

[Craig Seeman]

I think turning down the detail is a good suggestion.

I’ve had the twitter issue myself. What I think is happening is when you’re shooting 1080p and part of the subject resolves to only a scan line or two and you downconvert to SD interlace the resultant subject is about a scanline or less. Hence it will twitter as the fields alternate.

In my case the twitter was at its worst when shooting thin tree branches while executing a slow zoom.

Part of the issue is that the EX resolves to a much higher resolution than most cameras (including many more expensive cameras). I believe Adam Wilt did some chart tests and found it resolving to about 1000 lines. When you have an object resolving to just one scan line at that resolution and downconvert the result may be as I note above. You get a one scan line object that appears only one one of two fields.

I believe ideally one would have some Edge Detection Interpolation on the downscale so only such lines are “treated” (softened to spread beyond one scan line in the resultant downconvert).

[Don Greening]

Since I haven’t down converted anything else other than EX footage I have no frame of reference with regard to cameras like the Z1U. I have a friend with a the Sony Z7U that continues to have down convert and line twitter issues using Premiere Pro on a Windows machine.

My down converts are a lot better than they used to be with only a trace of line twitter and only once in a while. My next experiment will be to turn the edge detail all the way down to nothing and do another test. Right now it’s set at minus 20. The last project was combining footage from the EX and my XL2 for DVD. The result was that the viewer will be hard pressed see a quality difference.

Keep in mind that if you stay in HD there’s no line twitter from the EX.

– Don

[Olly Lawer]

I am at a cross roads of whether to send the EX1 back and get another camera. Before I do, I want to understand if anyone has managed to get a decent SD DVD from EX1 footage.

Noah has a DVD detailing how to down convert to SD (https://www.callboxlive.com)- but before I buy it, I wanted to find out if the EX1 is best for purpose.

I must admit, I did know the problems associated before I brought the Camera, but I was hoping the kenstone solution would work – the image looks good (before it goes to compressor that is and apart from the aliasing) although unfortunately it changes the aspect when I view it (even tho I haven’t selected 4:3) and squashes the image.

[Don Greening]

[Olly Lawer] “the image looks good (before it goes to compressor that is and apart from the aliasing) although unfortunately it changes the aspect when I view it (even tho I haven’t selected 4:3) and squashes the image. “

If you’ve selected 720×480 Anamorphic then it will be squished when you view it in Quicktime Player and before you send it to Compressor. If you exported from FCP as a square pixel 854X480 self-contained movie then Quicktime Player will display the movie correctly.

When you use Compressor to encode your Anamorphic movie just make sure you’ve selected Anamorphic (16:9) in the encoder tab when you’re setting everything up.

– Don