Studio with Physically Correct Lighting

[Speedster]

Hi all;

Happy New Year!  And to get 2017 off to a roaring start, I want to share my Photo Studio with "physically correct lighting".  As you know, I've been doing a lot of experimentation in the area of physical lighting, and decided to model some up based on my own lamps.  I know we use planes and spheres, etc., but I have to say, working with "real" lighting is a blast, and gives a very different perspective on setting up the studio.  It's kinda like playing with your sister's doll house when you were a kid, hoping nobody saw you!

This package has a photo table-top, a light box, and a variety of modeled lamps including the standard spots with barn doors and top hats, a soft box, umbrella, and several "Light Painting Wands" to play with.  The long Light Wand is ideal for things like the front struts on a motorcycle, and was actually  the seed for the famous "Hosemaster" lighting system invented by the renowned photographer Aaron Jones, to light his work on the Harley-Davidson catalogues. The light box can double as an "enclosed volume" if scaled up. I have not yet worked up a suitable translucent material for the light box that will properly transmit light, as used in fine product photography.  And of course each lamp can be duplicated, moved, scaled and re-proportioned X-Y-Z to suit.

Each lamp has several "light surface" options.  A filter disc can also be used as an effects filter, like wavy glass that throws a crazy pattern.  I have set up a basic rig to get you started.  But the main key is to play with intensity (wattage) settings and color, as well as positioning.

Above all, set your HDR Environment Brightness at zero, and render using the Interior Mode.  I use Maximum Time, usually about 20 minutes on 32 cores for a 3000 wide image.  Increase the HDR brightness a bit to make it easier to see the lamps when moving things around.  I included my fruit bowl with oranges as a starting point, but all you have to do is drop your model in and get started.  Without the light box or table top it becomes a regular empty studio.

So enjoy, and I hope this gives a butt-kick for you to play with physical lighting! Please post with credit, and be sure to share any tricks you come up with!

Bill G

[NM-92]

This looks fantastic and really interesting. I downloaded the file, so now i just have to find a good model to work with, or just revisit an old one. Thank you very much for taking the time to set this up. Cheers and happy new year.

[Josh3D]

Very cool, Bill. Thanks for sharing this!

[fario]

Hello and happy new year!
Thank you very much!

[jhiker]

Thanks for the opportunity to play with this set-up.
Just out of interest, why does changing the scene units (e.g inches to mm) affect the lighting brightness so dramatically?

[Speedster]

why does changing the scene units (e.g inches to mm) affect the lighting brightness so dramatically?

Interesting!  I had not noticed this, but a switch from (my) inches to mm really hits hard!  I remember this as a major issue when physical lighting was first introduced, but thought it was resolved now in KeyShot 6.  Maybe someone from the KS Team can clarify?

Also, Area Light Diffuse and Emissive seems to work best.  IES will not work on most of my lamps, which makes sense in that an IES profile is essentially a shaped and controlled light source in the first place.

And, as has been pointed out, physical lighting can produce "hot pixels", which I now think is a result of specific textures like scratches and roughness.  TBD... 

Again, this concept is really a WIP, and is not necessarily better than spending a few seconds adjusting an HDRI environment.  But I think it has its place in our sandbox!

Bill G

[Will Gibbons]

Thanks for the opportunity to play with this set-up.
Just out of interest, why does changing the scene units (e.g inches to mm) affect the lighting brightness so dramatically?

This comes down to understanding the Inverse-Square Law, which is a formula that explains how much light will fall onto an object based upon the distance it is from the source of light. Take 5 minutes to read about it here (well-worth it): https://www.ifa.hawaii.edu/~barnes/ASTR110L_S03/inversesquare.html

Note too, that a measure of watt is power consumption, not a measure of brightness, like lumen or lux. (Best to use lumen or lux)

When changing units in KeyShot, be sure to understand the difference between Correlation and Conversion. There should be no difference when converting, but when correlating, you're actually changing the distance the light source is from the object (and in some cases, the surface area of the light source). Also, in this case, IES profiles shouldn't be necessary if you're shaping the light via reflectors and other geometry.

[Speedster]

All good points, and thanks, Will!

In the old 4x5 and 8x10 studio days we used the ISL for all lighting rigs, but I did not equate that to the KeyShot Model Units.  We used to thro up a 500 watt fill, or 1000 watt spot, or whatever, then adjust using a tape measure and masking tape to spike the light stands.  Of course, lumen is the correct term and usage, and again, I did not make the connection to KeyShot.  All super info!

IES Profiles are already "shaped", so to speak, and work best on just a small sphere or whatever, adjusting by eye and with View Lights enabled.  Which can be very confusing with a lot of sources!

Thanks again!

Bill G

[Will Gibbons]

Agreed Bill. LEDs are about 5x more efficient than incandescent bulbs. I assume you used incandescent bulbs when for studio lighting?

A 100 watt incandescent bulb puts out about 1600 lumen.
A 1600 lumen LED only consumes about 18 watts.
Something to consider is KeyShot doesn't care/take into account what kind of bulb you're emulating... just the brightness, which is the reasoning behind the Lux/Lumen suggestion.

Cheers

[Artvps]

Thank you very much Bill for your light studio, much appreciated.
I downloaded it and gave it a go. I used a simple 2 light setup for this render using the softbox on the right, and the umbrella on the left.
The model was from http://threedscans.com/

Thanks again.