Camera target changes image brightness

[daniel_kreischer]

Hello.

When the project scale is set to millimeter or below, using a camera target with the target tag somehow changes the behaviour of the vray camera, resulting in a slightly (but noticeable) difference in the image brightness.
If you set the project scale to micrometers you can even see a distortion of the image, as if the focal lenght is set to a very low value.
I have tried to change the order of the tags and the prority of the target tag but only removing the target object sets everything to normal.

I've come up with a workaround for my project and I hope I'm not missing something but I think this is not an intentional behaviour.

I'm using Cinema 4D S24 with Vray 5.2

[sirio76]

Can you share an example?

[daniel_kreischer]

Sure I can.



Image A and the attributes (both are identical) on the left are the camera without the target.
You only notice it when you have two cameras, one with target and you change them through takes or animation. So not a big deal, but a bug after all I think.

Test scene
https://file.io/0ZC76brhwZNx

[aleksandar.kasabov]

Dear daniel_kreischer,

I apologize for the delayed reply.

Please note that this behavior is expected as the V-Ray camera is physically accurate and the camera focus affects the lens of the camera. Enabling the "Specify focus" option in the "Depth of Field" tab in the Physical Camera parameters and setting the same distance to the target object will make the results of both cameras the same. Please check this screenshot. I hope this is of help.