Need calibration/test scenes

Post by **OnoSendai** » Mon May 28, 2007 10:55 pm

I've added exposure duration (a.k.a. shutter speed) to the camera model.
I've also created a new tonemapping option, called 'camera' tone mapping.
This method takes two scalar real parameters - ISO film speed, and an exposure value (Ev) adjustment.

The general idea here is to create a realistic model of image generation by a digital or film camera. If you set the aperture radius (which is related to the f-stop value), exposure time (=shutter speed), film speed, and Ev adjustment, then you should be able to predict the image that the camera will generate.

Sooo....
what I need is some calibration scenes.
I need some indigo scenes that are modeled on real world scenes.
The lights sources need to be given the correct wattage (and efficacy), or the sun/skylight model needs to be used.
Plus, for each scene, I need a photo of the scene, with EXIF or other data containing shutter speed, Ev adjustments, f-stop, camera make/model, sensor size.

thx!

Kram1032 · Post by **Kram1032** » Tue May 29, 2007 12:00 am

great

0.9t1?

Post by **OnoSendai** » Tue May 29, 2007 12:04 am

Yes, this stuff will likely be released in 0.9t1

Kram1032 · Post by **Kram1032** » Tue May 29, 2007 12:05 am

Any other hints?

Or is the rest "top secret"

Zom-B · Post by **Zom-B** » Tue May 29, 2007 12:14 am

maybethis threadcould help...

otherwise a websearch for render to real world comparison should help

StompinTom · Post by **StompinTom** » Tue May 29, 2007 1:47 am

ive got a couple strobes at home, nothing too hardcore (a 100Ws and a 40Ws) but ill try to post some shots in the next couple days.
a good rule of thumb from when i was shooting film with a broken light meter was that on a sunny day, film at 100ISO, shutter at 1/125 and aperature at f11 makes for a good exposure. cloudy day, same settings except aperature at f5.6 or sometimes f8.
indoor concert photography is pretty shitty: 1600ISO, 1/15, f5.6 (thank god ive gotten a faster lens since then)
anyways, hope those give you somewhat of an idea.

Post by **OnoSendai** » Tue May 29, 2007 2:52 am

Thanks Tom,
At least I'll know if I'm vaguely correct.
And thx for the link ZomB.

carbon · Post by **carbon** » Tue May 29, 2007 3:01 am

hi OnoSendai, if you could be more specific about the scenes i can make them in professional photographic studio in which i work. you need for example tabletop which can be schematically modeled / or / photograph copy? as i can understand you need some light situation, exactly reproduced, right? if you specify exactly what you need, i can make it..

Kram1032 · Post by **Kram1032** » Tue May 29, 2007 3:49 am

he needs ANY scene, where he knows, how it's lit and how it's shot.
And, which can be reproduced by indigo.

Post by **OnoSendai** » Tue May 29, 2007 4:02 am

sounds good Carbon.
Tell me, what materials would you build the model out of?
And do you know the albedo (reflectivity) of the materials?
thanks,
nik

carbon · Post by **carbon** » Tue May 29, 2007 4:07 am

yes, but i don't think any is usable for exact measuring.. what i thought is some kind of real calibration scene, where can be everything measured, and exactly reproduced by indigo

carbon · Post by **carbon** » Tue May 29, 2007 4:11 am

don't have any idea yet, need any suggestions.. just have studio and equipment available

Marcofly · Post by **Marcofly** » Tue May 29, 2007 5:39 am

i would make an interior photo (just with light coming in the room from a single fenster, without artificial light) of a kodak calibration card, and measure with an exposure meter the direct light and the reflected light..
than build the room model in 3d.

carbon · Post by **carbon** » Fri Jun 01, 2007 11:18 am

i was thinking a little bit about (hard core working just now, hate short deadlines..)
so..
several critical light situations (overall soft, hard from side, contrejour lighting (it is in english? found in dictionary) from different directions.... etc), some different light sources, different exposures (equal combinations of f-stops + shutter speeds, and maybe some extra under and overexposures), simple scenes, everyday things - some for which material could be easy to set.. (eg, Al (i have no Au

), porcelain, glass,...)(i don't know how you others set your materials, but for it is still trial and error, a bit of intuition and experience and endless rendering of my preview scene).. and calibration cards of course.. and i can use canon mark which is 1:1 to 35mm

and Ono, would be possible to measure reflectivity as a difference between incident and reflected light intesity? i had exponometry on academy but everything forgotten..

zsouthboy · Post by **zsouthboy** » Sat Jun 02, 2007 5:12 am

Ono, are you considering doing some neat vector motion blur in Indigo?

Need calibration/test scenes

Need calibration/test scenes

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