Panasonic S1 Moire interview red t-shirt

[BjornT]

Hi everyone,

Last week I shot an interview on the S1 (in vlog, internal) and the subject is wearing a red t-shirt and there is moire on it (check top right of his shirt). I know that camera the dont have an OLPF filter and this could happen but pretty surprised as I have had zero issues so far filming stuff with much more complicated patterns and also the GH5 that was used as B-cam on the side has no moire at all. Bit disappointed that a normal red t-shirt would have moire in this sort of situation.

I wonder if people had some theories to why I got moire in this case? Might have something to do with the blue light in combination with the red t-shirt? (falcon eyes 818)

Also any tips on how to reduce it in Resolve would be most welcome:)

you can see a clip of it here https://f.io/dWW5vOgC

 

 

[rawshooter]

Simple explanation - the S1 doesn't have an AA filter/OLPF (as opposed to the S1H), see this article:
https://petapixel.com/2020/02/10/how-an-anti-aliasing-filter-impacts-a-cameras-photos/

So this is expected behavior.

[Geoff CB]

Thankfully it's on a solid color. Select the red of the shirt with a qualifier and use a little blur and it should reduce it.

[androidlad]

Yeah, a simple qualifier and a small amount of blur got rid of the moire:

It must have happened by coincidence - the texture of the t-shirt and the sharpness/focusing of the lens produced just the right amount of high frequency detail that the sensor could not resolve.

Maybe next time you can ask the subject to be shirtless, moire-free guaranteed and you'd get more views 😆

[BjornT]

Thanks for the answers guys.

 

I shot a few of my shirts today at home and did see moire on some of them too... Will be able to work around it hopefully on shoots but shot them with GH5 as well and no moire and that does not have an OLPF filter either which is why I am little bit bit disappointed it exhibits this... That said it is amazing otherwise.

[no_connection]

Since red is a primary color you only have 1/4 the area taken up by a receptor surrounded by a large black border. Same for the GH5, you probably just have to find the right distance.

[Jim Jones]

Were you shooting in 4k or 1080p? FF or APSC mode?

Can anyone who's shot those modes on the S1 confirm if the Moire is worst in 1080p FF mode?

Anecdotally the 1080p modes are a step down in quality due to the down sampling method used, but other people don't seem to report much difference and I'd like to know for sure before ordering! Cheers!

[BjornT]

On 8/17/2020 at 8:51 PM, no_connection said:

Since red is a primary color you only have 1/4 the area taken up by a receptor surrounded by a large black border. Same for the GH5, you probably just have to find the right distance.

Could you elaborate? Not sure I I understand. I thought I was getting moire due to texture and fabric of the t-shirt. But are you saying it has to do with lighting and the color of the t-shirt?

Jim Jones, It was shot in 4K in FF.

[no_connection]

1 hour ago, BjornT said:

Could you elaborate?

If you look at the red and blue part of the Bayer pattern you see that they each only cover 1/4 of the area. Meaning they are much more prone to moire than green or gray

You are correct that it's the texture combined with Bayer that causes the interference pattern, and without OLPF there is not much to be done about it, regardless of camera. Oversample does not really solve it but there might be software mitigations for some of it.

With enough sensor resolution you could argue that you are under the nyquist and would not get moire.