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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Ursa G2 Moire and IR protection rawlite OLPF

Dean Butler

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Coming from a Red dragon I wasn't used to seeing moire and IR contamination, still a fantastic camera I think and the rawlite makes it even better. Has anyone got the rawlite OLPF for the BMPCC 6k? (I assume plenty of people have them as B and C cams) 5:30 you see the Ursa G2 with 6 internal stops of ND + 3 external, then the BMPCC with 9 stops of Tiffen ND (no IR protection added) at 5:42. Nightmare fuel. (Not in the video but I did test the Breakthrough 10 stop X4 ND and that thing was super color neutral even on the 6k... Blew me away. I'm thinking of getting the 3 and 6 stop versions now.

 
Yeah I'm super interested to see ALOT of footage from that thing. Especially the 8k. Seeing moire, how it deals with IR color separation etc.

I think better colour discrimination is the main get from the 12K sensor design.

I do find so far the IR is similar to other BMD cameras, which we’ll call mild.

I own four of the RAWLITE OLPFs, which I mainly got for using with the G2 for improved IR with internal NDs, more than moire issues.

I am not yet sure if I’ll need them for the 12k, using “good” IRNDs rather than relying on the internal ND’s will likely be fine.

JB
 
I think better colour discrimination is the main get from the 12K sensor design.

I do find so far the IR is similar to other BMD cameras, which we’ll call mild.

I own four of the RAWLITE OLPFs, which I mainly got for using with the G2 for improved IR with internal NDs, more than moire issues.

I am not yet sure if I’ll need them for the 12k, using “good” IRNDs rather than relying on the internal ND’s will likely be fine.

JB

Hey John,

Thanks for your reply (And all the work you are doing sharing with us! I don't know how you find the time with all you do... I suppose there's a bit more time nowadays).

I'd call the IR mild on the Ursa Mini Pro for sure. On the 6k though, I think that's pretty bad for it (hard to complain at price though, just NEEDS an ir filter on there if shooting outside).

We may need to invest in some good IRND's for narrative work. Most of my paid work is fast moving corporate doco work so I'm riding the internal ND's. The rawlite filter was a no brainer for me.

I just want it all lol.
 
I'd call the IR mild on the Ursa Mini Pro for sure. On the 6k though, I think that's pretty bad for it (hard to complain at price though, just NEEDS an ir filter on there if shooting outside).

We may need to invest in some good IRND's for narrative work. Most of my paid work is fast moving corporate doco work so I'm riding the internal ND's. The rawlite filter was a no brainer for me.

I think the BMD choice of a less aggressive IR filter is often criticised, but it’s easily dealt with.

I think their thinking was that spectrum is continuous. You don’t have the any IR filter that hard cuts, they’re all slopes of some kind from visible red to infra red.

No one “sees” IR, and none of the light meters we cinematographers use measure it either, but it’s always there to some degree to another.

You can have an IR filter that’s too aggressive as well. If you cut off too much and put the slope over into visible red then you can start to affect skin tones especially.

So I think the logic is...You ALWAYS need an IR cut filter. Even in different filter brands you can see differences in how aggressively they work. A brand of IR filter that works well on one camera, may not work as well on another camera.

This is from a while ago, but take a look at these differences between the same filters, with and without IR cuts on Alexa and a 4.6K Ursa Mini

https://www.flickr.com/photos/johnbrawley/albums/72157673844822085

Notice with the Alexa, the with and without IR cut. The IR is bad on the Alexa without it, but introduce an IR cut and the infra red clears up in her top, but look how green the image goes...

JB
 
It's time someone comes up with a working digital IR cut filter(hard cut and steep slope) with little delay.
In theory the new 12k sensor should be able to support it with it's W-pixels(wide-spectrum).
I wouldn't be surprised when BMD is already working on it.
 
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