Camera Shutter Speed
leonardo_3285321d
Posts: 96
Hello,
I would like to recreate a real lightning situation so I setup lights with their lumens and spread angles values, I added walls and I setup the camera parameters.
I can't find the camera shutter speed and under tone mapping there is another f-stop parameter that I already setup in my camera.
Do you know if this is possible?
Thanks
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Comments
The f-stop in camera settings is for DOF, not exposure. As far as I can tell, the only parameter in tone mapping that really matters is exposure value; the other parameters don't actually mimic their real-world counterparts, but just get you to the EV you're after.
Changing Shutter Speed doesn't do anything other than control the amount of light entering the lens.
Until you render or use Create>New Tonemapper Options you won't have access to the tone mapping controls.
So from my understanding there is no way to simulate a real-world camera shutter speed to simulate the real-world camera exposure.
The tonemapping setting is not linked to the camera into the scene, but is just a separate parameters to set the exposure (not physically related to anything).
DS doesn't even have Iray motion blur at this time (Iray itself is meant to, I believe, I'm not sure why that feature is not currently suported or whether it will change) so no, the setting does nothing bu adjust exposure. Similarly fStop doesn't affect depth-of-field and ISO doesn't affect noise. The only reason to use the settings, rather than the main exposure setting, is familiarity.
That's a pity because what's the point in having lights with physical parameters (lumens, etc..)? At the end you can't simulate the real light with a given camera configuration. Hope iray will add this, or maybe some other renderer can already do it?
Do what? Motion blur (which is where shutter speed would matter - if the target is static then the shutter speed would have no bearing)? fStop/depth of field can be handled by setting both the Tone Mapper and camera values to match. I don't know why you would want to emulate the noise from ISO, but you could stop the render early.
Hello Richard, I'm not looking for motion blur, but I want to simulate the real lighting of a room given some lamp specs and a camera setup. I can setup everything else, but the shutter speed is missing from the camera settings and this will influence the quantity of light of the image. Let´s say I want to have a rendered image exposure that is very similar to a real picture taken with a camera.
Under Render Settings/Tone Mapping you should have Exposure Value, Shutter Speed, F/stop and Film ISO. I use them all the time.
@Fishtales yes, I know that but you can't reproduce a physical lighting with these parameters because the shutter speed there is completely unreal.
Try to create a simple room with few cubes and put a couple of 3000 lumens lights and a camera with 50mm, f5.6 and 1/200s
Why 3000 lumens. A normal 100 watt incandescent light is only 1500 lumens. I use lights and indoor settings on cameras all the time.
Hello,
I have OSRAM LED Star Classic A200 (datasheet attached) that are 3452 lumens each in my scene (3000 was an approximation, just to be not too specific).
Spread Angle in DAZ is 180 because I can't set 200 degree as specified in the datasheet.
So there are 5 lamp for a total of 17260 lumens (I know, it's a lot!) and my camera (A6000) is set with: Frame Width: 23.60mm (Sony APSC), Focal Lenght 16mm, Focal Distance 70mm, F/Stop 11.
A render with Tone Mapping Exposure of 12.00 (default with Shutter Speed 1/64s) you can see that there is a very dark image, seem very strange to me!
So my conclusion is that the shutter speed in tone mapping is inconsistent with reality. I am expeciting a very bright scene with such illumination!
What are the othert tone-mapper settings? The default is for bright daylight, not an artificially lit scene.
I only changed the shutter speed to 64. Other values are default one (fstop 8.0, iso 100.00, cm^2 1.00, gamma 2.2, etc..)
The data sheet says 470 lumens for the bulbs. It is 4.9 watts at 95 lumens/watt efficacy. The spread is 90º with the lumens still at 470.
That is beside the point as you have them set at 3452 lumens. For that scene I would lower the F/stop to 6.0 and raise the ISO to 400. I tested this in my light test scene and it lights it reasonably well. My scene has a spotlight, two linear point lights and 2 point lights spread around the room.
Hello Fishtales,
Sorry I attached the wrong datasheet, my lamp model is A200 (=200w equivalent, 24.9W) see new attached file.
In real-world this setup is much brighter than in DAZ for sure, this is the whole point. I can change DAZ tonemapping parameters to achive the lighting that I want, but I want to preview the real light setup before buying lamps.
By real world you mean eyes. Cameras don't have the computing power of our brain or or eyes to adjust for different lights, that is what the Tone Mapping/Camera Settings are for :)
For that image I would drop the F/stop to 6.0 or lower and the ISO to 400 or higher.
Have a read of this to understand what our eyes do and what we do in the camera to try and emulate that.
https://www.bhphotovideo.com/c/find/newsLetter/The-Photographic-Eye.jsp
I want to simulate pictures taken by the Sony camera, before setting up everything in the real world.
So I expect the DAZ rendering to match camera pictures. My eyes are out of the equation.
Are you setting up for portrait photography because photo spots have a temperature of 5000/6500 the lights you are testing are 2700 which is a very warm white?
Yes, these leds are warm white, they don't have an high CRI as well. Their strong points are the 9 euro price and a lot of lumens.
By the way I use an app called "Color Corrector" (https://www.majinsoft.com/apps/color_corrector.php) to accurately calibrate colors (ALL colors, not only the white balance) and save a lot of money.