Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: MARDUK on 2021-01-27, 07:30:24

Title: How do the correct numbers for artificial lighting correspond to corona lighting
Post by: MARDUK on 2021-01-27, 07:30:24

Hello friends
I experiment with indoor lighting without relying on the sun or the sky
Completely artificial lighting and I want to get results that are true to life
What I see here is that the numbers are way too high for proper lighting
Note : lux and Lumen

3 lights are placed by size 20cm .....
As shown in the pictures

the question :
Does it make sense that for every one of the lights I have to set 25000 lumen or 50000 lux ?
What is the real benefit of scale when it is in an LED case?
1800 lumen and 800 lumen and 2800 lumen
Room size : 6 meter - 4 meter
This does not even coincide with a review of sites that give me correct lighting for the room according to its size
And how much do I need lumen and lux
Title: Re: How do the correct numbers for artificial lighting correspond to corona lighting
Post by: Juraj on 2021-01-27, 11:20:45
Easiest unit to match to real-life source is LUMEN because it corresponds to total light emitted.
LUX is problematic because that is total light falling on surface so it accounts the angle of spread, etc..

If you have a light bulb with 1200 Lumen in reality (like LED from Ikea), if you create same size of bulb in Corona, give it 1200 Lumen, it will give you identical light.
But even if you make the size wrong, Lumen will still give the same total illumination.

Example: 4x4cm 1200 Lumen will give the room the same total amount of light as 40x40cm 1200 Lumen. Only the first one will give sharp light, and second one will give soft light. But same total light.

Obviously, you have to account for Exposure. If the room is dark, and your light units are correct, then your exposure is wrong. Both light units and exposure are exponential, so it doesn't matter if you add EVs or double the light units, but of course, more correct (while visually identical in nature) is the first option.
Title: Re: How do the correct numbers for artificial lighting correspond to corona lighting
Post by: MARDUK on 2021-01-27, 12:18:11
Thanks for your time, brother
But aren't these numbers too large to produce such light?

 25000 lumen or 50000 lux ?
Title: Re: How do the correct numbers for artificial lighting correspond to corona lighting
Post by: Cinemike on 2021-01-27, 16:19:03
What Juraj was saying is:
If you want a 4x6 meters room lit with 1800/800/2800 lumen and have it appear as bright as in real life (in a photo, don't trust how it would appear through your eyes, they will adapt to almost any lighting situation), you need to adjust your exposure to something realistic.
This means using a Corona camera that mimics values you would use in real life, too.
Photographic exposure with a high ISO (say 800), longer shutter speed (say 1/30s) with a wide open lens (1/2.8), as a photographer would use for a start.
Some photographic background is of use here, of course.

CU
Michael
Title: Re: How do the correct numbers for artificial lighting correspond to corona lighting
Post by: MARDUK on 2021-01-28, 13:55:29
Thank you for the clarification, brother
Use subtitles so maybe I didn't get it well
I now understood that I would have to replace it with my camera or general lighting