Help please, Shot with low light OLPF on IR setting in camera

[George Woodcock]

Hello. I am on a shoot and made a mistake. I was shooting bats last night on a IR filter and IR Olpf setting in camera. I then changed to a low light filter to film a night driving sequence. I completely forgot to change the Olpf setting in camera from IR to low light? Due to exhaustion and the picture didn't look crazy, Does anyone know if it Is possible to change in redcine from IR to low light setting? Any help will be greatly appreciated!

Thanks

george

 

[Chris Henze]

RedCine will re encode the footage for another olpf. You need the latest version. I think the procedure is to right-click the clip in the files window and the dropdown has the choice to change the OLPF. It then makes a new version of the footage. I also don't think it keeps the sound if there was any on the footage. It's no problem to fix.

 

[Ulf Krentz]

Chris, didn´t know that, wow, thanks! But not sure about that no problem to fix, though. I just tested to recreate a night shot which was shot with the STH OLPF and saved it to LL-OLPF, while it changed the color it did not change the grain structure and the pronounced red dots that don´t show up when shooting the LL (For that shoot we had a second camera equipped with the LL OLPF). It was quite easy to get the two versions to match in color by just adjusting ColorTemp and Tint. I have to do some in-depth tests - at the moment my guts feeling is there is some sort of different thing and tone-mapping in camera involved depending on the selected OLPF when shooting that just can´t be reversed later. I might be wrong… Any insights, Graeme?

 

[Chris Henze]

From what I understand the raw data from the sensor goes through a first step of math that adjusts for the OLPF. Once this is done the RAW is ready for other work. I suspect that what happened to you is an optical change resulting from the coating on the OLPF. If you're satisfied with the way the color temp and tint look then you're done. I've seen it be close but some colors will go wonky. I did some testing and actually chose the wonky color as it had an unexpected result which I liked. I think I used the LL OLPF with the ST setting.

Here's what it looked like

 

[Ulf Krentz]

Thank you for getting back. I´m definitely planning to further explore this topic. I´m particularly interested to shoot the STH OLPF with the LL setting in camera and reprocess it (now that I now there is this option) than compare it with the proper STH OLPF and setting. Probably I´ll find out the Standard OLPF is what I´ve been wanting for though, that´s next on my list...

 

[Derek Morrison]

Wow glad i read this, thats so great, I can fix some old footage now!

 

[David Battistella]

Still.

It is important that not all OLPF's are created equally and they do have very different optical characteristics. The RCX "fix" is meant as a fix and does not alter the optical path. Like if you shot with a certain type of filtration that will be baked into the file and this is more a way of reprocessing under the hood. The various OLPF's do alter the spectrum before light hits the sensor.

David

 

[Ulf Krentz]

David, sure, but that´s not what I´m thinking about. I doubt that the red noise and grain structure is based on the actual optical characteristics of the OLPF itself, this and also the highlight rolloff seems more related to a sort of programmed tone mapping that is based and applied on the actual OLPF setting in camera. On the other side it may be just an approach to "a unique look" resulting from the inaccurate colors like Chris pointed out. Just thinking out loud and exploring boundaries, as I really like to in depth know my equipment

Cheers
Ulf

 

[David Battistella]

Ulf,

It my testing it is. With the STH the grain structure is considerably different as the diffuse light is hitting the sensor differently. I might be splitting hairs but it is obvious in say a side by side test with the exact same lens between the LLO and STH. So, like an optical path, it does tend to create subtle differences which you can see and (may or not be) perceptible.

Also have to consider what is being encoded into the file and how the OLPF affects compression, again slight, but, there.

David

David, sure, but that´s not what I´m thinking about. I doubt that the red noise and grain structure is based on the actual optical characteristics of the OLPF itself, this and also the highlight rolloff seems more related to a sort of programmed tone mapping that is based and applied on the actual OLPF setting in camera. On the other side it may be just an approach to "a unique look" resulting from the inaccurate colors like Chris pointed out. Just thinking out loud and exploring boundaries, as I really like to in depth know my equipment

Cheers
Ulf

 

[Ulf Krentz]

Ulf,

It my testing it is. With the STH the grain structure is considerably different as the diffuse light is hitting the sensor differently. I might be splitting hairs but it is obvious in say a side by side test with the exact same lens between the LLO and STH. So, like an optical path, it does tend to create subtle differences which you can see and (may or not be) perceptible.

Also have to consider what is being encoded into the file and how the OLPF affects compression, again slight, but, there.

David

Thanks for your reply, so if I read this correct you already did a test with intentionally "wrong" OLPF settings and end up in also getting the different grain structures? (Comparing results of the physical STH OLPF shot with LL OLPF settings against LL OLPF with LL OLPF settings) The differences of the grain structure of the LL and STH OLPFs with their corresponding camera settings is thoroughly pronounced to me and I prefer the LL grain, which feels more organic. Might need to bury the idea And still have to check the standard OLPF.

 

[David Battistella]

No, I did the tests with the correct OLPF setting for each OLPF. I get what you are thinking about though. People also went through this with Blackshading, using an incorrect black shading calibration, using say a 360degree shutter blackshading with a 172degree shutter while capturing. not highly recommended but artistic none the less.

David

Thanks for your reply, so if I read this correct you already did a test with intentionally "wrong" OLPF settings and end up in also getting the different grain structures? (Comparing results of the physical STH OLPF shot with LL OLPF settings against LL OLPF with LL OLPF settings) The differences of the grain structure of the LL and STH OLPFs with their corresponding camera settings is thoroughly pronounced to me and I prefer the LL grain, which feels more organic. Might need to bury the idea And still have to check the standard OLPF.