Real World Diffuse, Specular, NormalMap and Light

[dubcat]

I had some cheap 3D glasses laying around after last cinema visit. I tore them apart and taped one of the glass parts onto my flash. The other part was handheld, since I have to rotate it 90 degrees. Thought I could share the results in case someone are interested.

The first picture is about 50% diffuse and 0% specular
The middle picture is around 38-50% diffuse and 76-100% specular
The last picture is 0% diffuse and 100% specular

Some of the results are more interesting than others. The cement result is interesting.

I'm thinking about getting some proper filters, could get some really good spec/bump maps from the 100% spec pictures.
The pictures are save as 5Q jpg, the forum has a 30mb upload limit.

[maru]

Did you invent this yourself? :D

[dubcat]

Did you invent this yourself? :D

I read THIS article 5 years ago. Using cheap 3d glasses instead was something I came up with myself.

[dubcat]

I forgot these.
Funny how the handbag looks dirty as hell without spec.

And here is a test I did to see how desaturated a normal image is from the real diffuse



I'll buy a new tripod. If there are any specific materials you want to see, just leave a comment.

[Ludvik Koutny]

This is crazy. I would have never thought you can do this yourself at home. It actually gets me really interested in capturing custom textures.

BTW that plush companion cube.... <3 <3 <3 <3 <3 <3

[dubcat]

This was a test to see how stuff with SSS behaved. I found this really hairy disgusting soap under my bathroom sink.

[maru]

I think I have polarizing glasses from cinema somewhere.......

[romullus]

I disassembled few lcd screens last year, so i have plenty of polarised film. Did take some pictures with them to get specular free textures. Never knew i can use it to get specular component out of pictures, though. But how do you apply a math expressed in aforementioned article? Through photoshop layer blending perhaps?

[dubcat]

I shoot RAW in full manual mode. Then I import the pictures into Photoshop and in 32 bit mode use (Subtract). It has to be the Albedo that is subtracted from the specular.

I turned the specular to black and white to see how the result would be.

Added picture of my new kit. I read somewhere that it had to be linear filters. Guess it was a lie,  because I get the same result with my new circular filters.

[dubcat]

I've upgraded my kit again. The camera flash was too harsh and gave me problems when the room was too dark, since I need longer shutter. I have mounted a 110 lumen LED flashlight with parchment paper in front to diffuse the light.
I took some test pictures of an old white wall, the pictures are calibrated with ColorChecker this time. The only light source was the LED flashlight, 3 sec shutter.
I want to diffuse and spread the light even more, maybe I can add another layer of paper or fabric.

Fascinating how the 100% spec maps show dirt that you normally don't see in real life.
I think the paint is "Egg White", after calibrating the pictures the paint ended up as 168-169 RGB.

[romullus]

Added picture of my new kit. I read somewhere that it had to be linear filters. Guess it was a lie,  because I get the same result with my new circular filters.

I don't think it's a lie. Circular polariser has additional filter glued to it, which changes polarisation. So the one that is attached to light source should be linear to get best results... unless you mount cir-pol filter in reverse (i.e. inner thread pointing to light source), that maight work :] What kind of polariser is attached to camera lens doesn't really matter.

I've upgraded my kit again. The camera flash was too harsh and gave me problems when the room was too dark, since I need longer shutter. I have mounted a 110 lumen LED flashlight with parchment paper in front to diffuse the light.
I took some test pictures of an old white wall, the pictures are calibrated with ColorChecker this time. The only light source was the LED flashlight, 3 sec shutter.
I want to diffuse and spread the light even more, maybe I can add another layer of paper or fabric.

Your LED flashlight has smaller surface area, so it should give you even harsher light. Also camera flash has 100% CRI, while LED gives you 80-90% at best. You want highest possible CRI for that kind of job, i guess. I'd stick with flash. Go full manual and you'll be able to find aperture and flash output combination that gives correct exposure in pitch dark room. Also set widest possible zoom on flash and use built in diffuse filter if 430 ex has such to eliminate vignette.

I shoot RAW in full manual mode. Then I import the pictures into Photoshop and in 32 bit mode use (Subtract). It has to be the Albedo that is subtracted from the specular.

I turned the specular to black and white to see how the result would be.

Somehow i think that math in Filmic games article is a bit more complex than that, but that is just my personal opinion not based on experience :]

[dubcat]

Thanks for the feedback. I will tape one of the 3D glasses onto the flash again and test the setup you are talking about.
The math is 100% the same as filmicgames script, it just looks intimidating since he has to convert between Linear and sRGB, attached comparison image.

I will post the flash results when they are done.

[dubcat]

Here are the results from the flashlight/circular vs flash/linear test.
There is still some spec left in the flash/linear albedo, this is my fault, I didn't notice it before I opened the picture in Photoshop.
The pictures are not ColorChecker calibrated.
The nice thing about the flashlight is that I can use "Video" mode to tweak the filters, while with the flash I have to take a picture and look at the results.
This test was in a pitch black room, I'm going to compare them outside soon. There is a thunderstorm outside right now, so if I don't reply I've been struck my lightning and bitten by a cobra.

EDIT: So i did some tests outside. Only the flash version works, we need a bright light source.

Conclusion:
Dark room = Doesn't matter, easier to use flashlight because of video mode.
Bright room or outside = Flash

[CiroC]

This is great stuff dubcat. I read the same article and I wanted to buy a filter for the lens, but in this case what type of 3D glasses did you use?

[dubcat]

This is great stuff dubcat. I read the same article and I wanted to buy a filter for the lens, but in this case what type of 3D glasses did you use?

It's those standard cheap plastic glasses that you get from the cinema when you are watching 3D movies. The circular filters are HOYA CIR-PL filter, paid around 22€ each, they are very hard to turn.
Attached a crappy mobile picture of it.

Edit: I would recommend attaching the filter to something, your fingers get really messed up after a while. I have taped mine onto a latte spoon.