Trying to reduce moire - New OLPF for Dragon in NY?

[Matt Lowe]

Hello All,

I'm in quite a time crunch, and tried to post this in the Want To Rent section, but I don't have sufficient privileges yet to post there... I apologize for the misplaced thread, but I'm hoping someone can help point me in the right direction.

Basically, I'm wondering if there are any of the new OLPF's floating around in the wild in NY. We're shooting a multi camera production this week that has someone standing in front of a giant LED wall (i know, I know) and we're trying to reduce the Moire as much as possible. I'm hoping that the new OLPF's for the dragon would be able to help with this.

Any help would be greatly appreciated. Thanks!!!

Best,
Matt

 

[Bob Gundu]

There has never been an issue with any of the OLPF with Moire on the RED cameras. You should be fine.

 

[Matt Lowe]

When you shoot an LED Wall there is a whole world of Moire, especially if it's dead on, no matter what camera you shoot with. We're trying to reduce that as much as possible.

Would the new OLPF's help with an LED Wall better than the old ones? The metadata of the red footage I'm looking at right now says there is no OLPF on the Dragon that we used

I wasn't on the test shoot so I can't attest to what settings they used, I can only see the footage that I have in front of me.

 

[Phil Holland]

When you shoot an LED Wall there is a whole world of Moire, especially if it's dead on, no matter what camera you shoot with. We're trying to reduce that as much as possible.

Would the new OLPF's help with an LED Wall better than the old ones? The metadata of the red footage I'm looking at right now says there is no OLPF on the Dragon that we used

I wasn't on the test shoot so I can't attest to what settings they used, I can only see the footage that I have in front of me.

I strongly doubt that their was "no OLPF" in there unless somebody modified that camera. The real question is to find out if they used a Motion Mount or not as that's the one thing that could generate a potential moire situation.

Generally speaking the Skin Tone - Highlight OLPF will give you the best results with sources like this and I'm mostly referring to flare. If there actually a moire concern, and I'd really need to see this in person to find out you can try some sort of softening filter in front of the lens. Thought I'm fairly confident you wont need it.

 

[Bob Gundu]

Perhaps I'm confused. Maybe you are referring to rolling shutter/cmos problems associated with LEDs?

 

[B Newberry]

When you shoot an LED Wall there is a whole world of Moire, especially if it's dead on, no matter what camera you shoot with. We're trying to reduce that as much as possible.

Would the new OLPF's help with an LED Wall better than the old ones? The metadata of the red footage I'm looking at right now says there is no OLPF on the Dragon that we used

I wasn't on the test shoot so I can't attest to what settings they used, I can only see the footage that I have in front of me.

If this is the shoot I was on in Las Vegas with a certain comedian, It was the V2 OLPF and no motion mount.

 

[Gavin Greenwalt]

Just a note that if you don't do a 'Full' debayer it will be very Moire-d. Whenever doing comparisons you need to be sure to do a full debayer. That's caught me up before when I was just testing footage before doing the full render.

 

[Jeremy Hildebrant]

I did a shoot(Epic MX) with a 30' wide LED panel wall in the background. Luckily focus was on the subject in foreground, because it definitely moire'd when focus was tack sharp on the LED wall. MX has quite a strong OLPF also, so maybe once those LED dots line up with the sensor pattern there's not much you can do except for defocus a bit or move the camera closer or farther to change how the dot patterns line up...?

Also sometimes it is just the display device and the size you are viewing it at that is exhibiting the moire.

 

[Keith Putnam]

Your best course of action is to have the LED wall as out of focus as possible. If the LED wall has to be sharp, you'll need to experiment with camera placement and distance to try to reduce moire as much as is feasible, OLPF will not help significantly with moire. Also, as mentioned above, moire can appear on a display due to scaling and yet not be present in your actual recorded image, so be sure to punch in 1:1 to check for "real" moire.

 

[David Battistella]

Your best course of action is to have the LED wall as out of focus as possible. If the LED wall has to be sharp, you'll need to experiment with camera placement and distance to try to reduce moire as much as is feasible, OLPF will not help significantly with moire. Also, as mentioned above, moire can appear on a display due to scaling and yet not be present in your actual recorded image, so be sure to punch in 1:1 to check for "real" moire.

This. Hyperfocal distance is your friend in this case. Whenever we deal with a lot of moire (high resolution pictures) in post. It was common to out a .2 pixel blur on the images to reduce or eliminate the moire. The best thing to do is set this up in a way that the LEDs are just beyond the "in focus" part of the hyper focal distance and get the slight softness while still sharp look (if that is what you are going after)

Battistella

 

[Björn Benckert]

This. Hyperfocal distance is your friend in this case. Whenever we deal with a lot of moire (high resolution pictures) in post. It was common to out a .2 pixel blur on the images to reduce or eliminate the moire. The best thing to do is set this up in a way that the LEDs are just beyond the "in focus" part of the hyper focal distance and get the slight softness while still sharp look (if that is what you are going after)

Battistella

Yes what david says is right...

But shooting led screens is a real pain. we did a job when epic was new and we had no playback in camera etc. We saw huge moare allready on the screens, the DOP and I insured everything would be allright as we stupidly enough though it was only on the scale down HD output signal... Well that was not the case it was all over the place. Basically some of those led screens are simply not built to be shot. The leds are to few and far appart and will basically jinx any pixel array. So keeping them heavily out of focus is one trick but even then the blue,red and green leds will make odd patterns and such when camera is moving or picture on screen is changing. So there is no real good way of doing it.
Foreground action will get really odd glaring from the screen and it's super difficult to make the screen look good....

Our project was a "fake time slice" thingy and we actually ended up using still plates and mapping the whole scenes out in 3D... which saved us from a reshoot in that particular case, but that escape way would not have worked for many other situations.

I would actually rather give the screen a pure green or blue and then insert the imagery into the screens in post. Even thats a risk as the leds might bleed and not work well as a green screen.. so possibly filter infront of the leds... or tell the client it's not such a good idea...

here is links to the result of our struggle... did not look to good to say the least and the cg rescue operation took weeks.

https://vimeo.com/31208383

But if you have to do it keep camera fixed, make sure you have a fast enough lens so you can open up so that the screen is out of focus while the foreground is in focus.. or basically make sure there is no moare. If the screen is what should be in focus then yes it's a bit of a trick to pull off...

Also you might run into refresh issues and such but that you will also see on the screen while you shoot. but having the camera and screens at the same refresh / frame rate is important.