Camera settings difficult to understand

[frv]

I haven't rendered for a few months and somehow I can't get the camera settings to do much if at all.
There are four settings that can override to do nothing or all :
- Corona preferences
- Corona VFB
- Corona tag attributes
- Camera Attributes

I can set the VFB when I use the simple exposure settings but any other way to control exposure seems without effect.
I have attached a file. The only way to control exposure is by simple exposure. Other ways by setting shutter speed or aperture have failed to have any effect.

Any help appreciated.

[TomG]

Don't forget to add the Photographic Exposure control in the tone mapping if you want the camera override to have an effect, see https://docs.chaos.com/display/CRC4D/Corona+Camera+Tag

[frv]

Thanks Tom, for your quick reply. It still does not have any effect. I attached a default scene file. Maybe you can reply by setting that file with a camera to use aperture and shutter speed. I am not able to whatever setting I try. Since there are so many ways to control exposure by camera or not there must be dozens of ways to go wrong or right.

[frv]

I found it. Thanks. But you really need to get this part of the UI more obvious. I will have forgotten this work around in a few months and will ask the same question again.

[frv]

You are aware that ACES OT does not work or greys out the image with photographic exposure ?

Another thing is that LUT's behave totally different under simple exposure. See attachments. I even wonder if the LUT's properly work if set at photographic exposure.
When I set the LUT for Kodak Portra 400 at simple exposure it looks great (blueish) as I expected it would with this LUT. This LUT with photographic exposure seems off and a bit magenta.

[romullus]

Your order of operators are all over the place. You're comparing simple exposure before LUT vs photographic exposure after LUT Of course you will get different result (incorrect in case of photographic). And as a rule of thumb, almost all operators should be above ACES OT. It doesn't make difference in your specific case, because ACE OT is turned off, but you always should try to maintain correct order, unless you really know what you're doing.

[frv]

I had no idea you can change the hierarchy of the tone mapping settings. Which is logical if you understand LUT's. Anyhow, thanks for your comments since now I have a better idea how to manage tone mapping.

[frv]

I also wonder if there is any reason to use the photographic settings  ? Maybe simple exposure is all you need to get as good results.

[romullus]

I never use photographic exposure. Simple exposure does exactly the same job and it's much easier to control with a single parameter. By the way, if you want to learn more about Corona tone mapping operators, then do visit its documentation page here: https://docs.chaos.com/display/CRC4D/Tone+Mapping+Operators

[frv]

When using DOF I assume you need an aperture setting and photographic exposure.

Anyhow, Tone mapping requieres a lot of trial and error.  I would love to see the proper order for tone mapping settings for using LUT's

[romullus]

Not necessarily, you can use aperture for DOF and shutter speed for motion blur and at the same time still use simple exposure to control exposure. Corona is very flexible about that and doesn't force you into single workflow.