Another physical cam exposere question.

[pixelstudio]

Hy there people,

I'm tryng to get the balance correct between my model, the sky and the IES light,
I searched the inter for "basic camera settings". this is what i found:

Base Exposure 1/125 f/4 ISO 200 Typical normal exposure.
Fast Subject (adjust aperture) 1/500 f/2 ISO 200 Shutter speed is faster but depth of focus is narrower.
Fast Subject (adjust ISO) 1/500 f/4 ISO 800 Shutter speed is faster but picture is grainier.
Huge Depth of Focus 1/4 f/16 ISO 200 Depth of focus is very deep, shutter speed is slower.
Low Grain Needed 1/60 f/4 ISO 100 Picture has fine grain, shutter speed is slower.


So i thought i try this settings in a test scene.
All materials have a default grey (vraycolor map at 128 grey, 2.2 gamma)
All stuff is in gamma 2.2, and very loq quality for Irmap and Lightcache.



Have a look at the renders!,.
The first three images look reasonable except the sky/environment is way to white.
The 4th image looks okey for the sky, but the rest is to dark.

So how do i get this balanced so that the sky look correct and the interior is also correct ?

[tct70]

I was under the impression that the exterior should be over exposed with interior shots.

[zeronove]

I believe the only way to go is blending together a set of shots with different exposure

[^Lele^]

just like for real photography, indeed

[dlparisi]

The first three renders are correct for the sky exposure. If you really want it to look like the last one, you can put the vray sky into the v-ray environment overrides and put a new output map into the 3ds max environment with a vray sky in that output map. Adjust the output level as necessary (down).

[rmejia]

You could fake it combining two images, or add some windows with tinted glass, or raise the illumination of the interior with lights to try and match the inside with the outsides illumination level.

[raymarcher]

Yes, the light behaves just like in reallife, on film sets they put dark filters over the windows to compensate for that. So as you see even in real life you still have to cheat.

[pixelstudio]

Hmm well, what i'm trying to achieve is matching my cannon 400D settings with my images.
however the overblowing of the sky seems a bit much when comparing it to a photo.

althought you all say it's correct.. hehe

another question.
A collegue whas trying out vrayIES lights. he had to put extreme large numbers in the power to have a little light fom them.
so i search this forums and the most suggestions were:

- make sure the scene is modeled in correct units.
- balance your scene out (sun/physicalcam)

How can i make sure that the power/light comming from a IES is as it would be in real-life?
is there a "rul-of-thumb" that you people are using with interiors that have a good balance with IES lights ? and how do you test the power of a IEs light. for example do you disable the sun/sky and then testout if the IES gives enought light orso ?


cheers

[samuel_bubat]

That´s exactely the problem (reason) why Photometric exposure is useless in Archivz !
"Realistic looking" and "Photorealism" can be two completely different things.
Just use Max internal Logarithmic Exposure or Vray exponential exposure to come round
this behaviour. Even if you would find a trick (and there are many.. one worse than the other)
by tweaking Multiplier or dummy Lights etc etc... your image would not be physically
correct at all.. because you don´t have physically correct materials.