Aperture Width and VrayPhysicalCamera

I’ve got a technical question about how cameras work in Max and VRay, most likely for Vlado to answer:

Starting in the Max render dialog just above the resolution buttons is a box marked ‘Aperture Width(mm)’ which defaults to 36.0

Moving on to a VRayPhysicalCamera the first dialog is ‘film gate (mm)’, which also defaults to 36.0

My question is this: If I want to do a camera match with a full-frame Nikon D800 what do I set these values to? Back in the Max Render dialog there is a pull-down preset called ‘35mm (24mm x 36mm) (slide)’ which I assume tallys with the sensor on my Nikon. When I choose this preset the Aperture Width(mm) dialog chages from 36.0 to 34.2. Does this mean I need to change the VRayPhysicalCamera dialog ‘film gate (mm)’ to 34.2 as well?

It’s damn confusing! Any help would be gratefully received.

The physical camera ignores the Aperture value in the Render dialog. So you have to adjust the value there separately.

Best regards,
Vlado

Thanks for the clarification Vlado.
I have done some poking around and discovered that the film gate of a full frame DSLR, such as my D800, is indeed 36.0 and not 34.2 as Max suggests. I have no idea where the 34.2 value comes from.