F55: Shooting internal 4k at 320 iso

[Sami2]

I am trying to record internal 4k at 320 iso in cine ei mode however when i switch from hd to 4k the baking of lut to internal recording turns off and remains gray.

So is this once again feature?

 

[starcentral]

which item in the menu exactly is greyed out?

 

[Sami2]

in the menu the one that is greyed out is: video -> Monitor LUT -> Main & Internal M LUT off

So as I set the exposure index to 640EI the internal 4k is still recorded at base iso 1250

So what is the correct method to record internal 4k at 640 or at 320 in slog3?

 

[surinder]

The internal recording will always be at iso 1250 when in Cine EI mode

The EI value will change the viewfinder brightness only allowing you to expose to the right of the histogram For example if you rate the camera with a lower Cine EI index you will have less noise in your recorded file. You lose a little highlight headroom by doing this. If you rate the camera at a higher EI it will favour the highlights at the expense of noise in the shadows.

Basically the recording is always at iso 1250 for the f55 and iso 2000 for the F5 and FS7.

Hope this helps.

Surinder.

 

[Sami2]

so there is no way to record internal slog3 4k at 640 iso?

I would like to do this in order to get less noise, at hd recording this can be done in cine EI hence te field is not greyed out.

 

[surinder]

You will have less noise if you rate the EI lower. The recording will be at iso1250 but because you are exposing to the right you will have less noise in your recorded files.

Take a look at this aricle by Alistair Chapman it will help you understand Cine EI modes. The article is written for the F55 and F5 but is also applicable to the FS7.

http://www.xdcam-user.com/2013/12/cine-ei-mode-when-recording-s-log23-and-raw-on-the-f5-and-f55/

 

[surinder]

so there is no way to record internal slog3 4k at 640 iso?

I would like to do this in order to get less noise, at hd recording this can be done in cine EI hence te field is not greyed out.

There is a way around but you will lose the ability to use the Sony LUTs to delog the footage in post and to use MLuTs.
You can opt to use Slog as a gamma choice when the camera is set to Custom Mode. This way I think you can change your Iso. I'm exploring this avenue currently.

 

[Sami2]

As i tested the custom mode i was only able to increase iso with slog, not decrease at all from 1250.

If i record raw i am able to get the iso down in cine ei mode, however same does not appear to apply with internal 4k

 

[starcentral]

In custom mode you can not shoot lower than the cameras base ISO. 1250 in the case of the F55. So in custom mode to get 320ISO you'll need to stack on a .6 ND filter.

As for your greyed our MLUT option in the menu make sure you've set a look profile up first, ie. select an actual LUT.

Lastly choosing 320ISO in the CineEI mode still records using 1250ISO but causes you to overexpose by two stops when properly exposed.