Lights are too dim.
Midyin
Posts: 221
I have the lumen turnt up to 3000000 and its too dim. I've tried rendering with all my lights(11 all togeather) turned up to 25000000 each, and its still not any brighter.
My lights are inside of the room, so I seriouly have no clue why they would be so dim... -_-"
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Assuming you are using Iray : Make sure you have Environment Mode (Found in Render Settings:Environment) set as either Scene Only or Dome & Scene
If its not that then perhaps post more info on what set/lights you are using etc then someone who has it can advise you more
I know those numbers sound big, but they're not.
Change the units to kcd/m2 and use numbers like 3000 to 5000 as a starting point. Falloff distance is squared I believe so distance from the light-source is important.
Are these mesh lights? If so check they're facing the right way (you can turn on double-sided, but that might waste a lot of processing power if you don't need it).
If they're spotlights or pointlights, check that they're not half-hidden behind a wall.
Another thing to look at is the Tone Mapping tab of Render Settings - you can increase the Film ISO or decrease the value of shutter speed.
The weirdest part is the fact that the higher i turn the Lumen the darker it seems to get. like WTF? lol
My settings are currently 11 Spot Lights with their light geomitry set to Point. Intensity(though i know its not doing anything) is maxed out, along with my "Spread Angle" and "Beam Exponent". I have the Render Mode is set to interactive, and my shadows are all set to Raytrace.
I like how much better IRay looks over 3Delight, but honestly, So many people have so many lighting problems with it, i'm starting to think it just broken.
There is something else going on in your render. This is one spotlight set to point and the default 1500 lumens I then used Tone Mapping to get the light the way I wanted it.
https://www.daz3d.com/forums/discussion/comment/2898646/#Comment_2898646
Don't max out spread angle - that won't direct enough light in one direction. And definitely don't max out beam-exponent - that'll make it darker.
Leave beam-exponent at 4, spread angle so that it's focussed on an area the camera's pointing at, and try setting the lumens around 1,000,000.
They're dim because you haven't changed the Exposure Value (found in Tone Mapping). The default value is 13, which is a bright cloudy day. A good start for an interior would be between 5 - 7.
People either don't know or forget that Exposure Value needs to be set for every scene. Rather than ramp lights up to extreme values, set the Exposure Value first, then adjust the lights.
You can find a list of values here.
https://en.wikipedia.org/wiki/Exposure_value#Tabulated_exposure_values
the only other thing i can think of is the fact that everything in my scene is scaled up to 1500 because the main subjects are fairies,
When i tried scaling them down i had problems with being able to get the camera close to them without them dissapearing, so I scaled them up to 50% and scaled everything else up to giant size to create the illusion of them being small. BUT I scaled up the lights too, so that shouldnt be a problem...
You could try zooming isntead of dolying to get close to the fairies - right-drag on the magnifying glass icon in the top-right corner of the viewport, instead of left-dragging (which dollies). Making the scene huge will require more light, as a large room would compared to a cubby-hole.
What if I double my lights? like put two lights overlapping eachother both set to 3000000 Lumen..
If you aren't getting light from what you already have adding more wont make a difference. I'm still trying to get my head around the resizing, and why. If you make the faeries bigger and then make everything else bigger then the faeries will still be smaller :) The way to get the scene you are looking for is to only increase the size of the prop near the faery and leave the background as is. That way the faery will seem small in comparison to the surroundings with the right camera angles and with very little need to zoom in and out. Changing the lens size, wide angle or zoom, and zooming in or out can also change the perspective with distant objects seeming closer or farther away.
Yeah, but thats the idea. the cliant wants the faires to be 3 inches tall.
Inverse square law, if you double the scene size you would need to quadruple the lights - since you have scaled the scene to fifteen times normal you need two-hundred-and-twenty-five times as much light (if I am thinking this through correctly). Assuming that these are local lights, not distant lights which have the same intensity across the scene.
As already stated you need to adjust your Exposure to get the lights to the right brightness.
Ok, I completly missed Macleans comment...
I took Richard Haseltines advice and cranked the lumin up to 45000000. the render is plenty bright enough now, but the cones are pretty obvious and the shadows are very sharp, so I'm going to do as Silent Winter said and turn my beam-exponent down to normal, and try playing around with the Exposure... Fingers crossed all this togeather will make the render look good and be plenty bright enough to look as though the room is lit up in a realistic way.
Ok, I did everything I said in my last post and set my Exposure to 7, and my last render was almost pure white, BUT thats a good thing. that means that the changes I made did something, so now all i have to do is turn my lumen back down and start experimenting until i get the right look...
Thank you all for your help. Exposure is a powerful/helpful tool that i wont soon forget. :)
One other good thing about using the Tone Mapping settings is that you can adjust them mid-render.
There's a hard to see little button about half-way up the render window on the left side. Clicking it expands a menu that lets you adjust things (during or after render completion). So if your render is looking a little dark/bright, you can adjust the Film ISO/Shutter Speed/Exposure Value without having to restart your render.
(You can also set render-converged ratio / max time/iterations if your render needs more time to look good).
Did you remember to turn the Intensity back down to the default value? Intensity is a 3Delight-only parameter, it shouldn't be used for Iray lights in an Iray render. Leaving it up at waytheheckupthere values can cause Weird Stuff™ to happen.
Note that Iray lighting is very different from 3Delight lighting, the tricks and techniques you learn in one don't always have a predictable result in the other.
Late with these I know, had Studio problems. Running the Beta in the background with a render, while doing this on the full version, and it crashed, after four hours rendering :)
Anyway, I loaded up an old scene and added some faeries.
Lighting is a Plane for the ceiling, The original set only had two walls so I had duplicated them and swung them around to form a box and added a plane for the ceiling. I made it Emissive at temperature 2750; Luminance 1.50 cd/cm^2. The reading lamp is also an Emissive set at Colour 1.00:047:0.12; Temperature at 10000; Luminance at 1000.00 cd/cm^2. There is a snow scene HDRI in the Dome set at 0.5 and Tone Mapping is Shutter Speed 60; F/stop 8; Film ISO 300.
The Faeries is a Genesis 3 Female and one instance scaled to 5.5%. Going by her height on his shoulder that looks around 3 to 4 inches :)
2017-10-15 19:53:02.507 Total Rendering Time: 2 hours 42 minutes 41.85 seconds
Stopped.
2017-10-15 22:07:35.990 Total Rendering Time: 1 hours 55 minutes 41.95 seconds
Stopped
Here's a render I did with Emissive materials only. The only 'lights' in this scene are 2 large planes with Emissive value set to 75,000, the streetlamps (same value), and the traffic lights (default value 1500).
In Tone Mapping, Exposure Value was set to 3.00
Every scene is different and I've found I always have to play around with the balance between Tone Mapping and light values to get it right. But once you get the hang of it, It's not too difficult.
That's a good point that I don't think is brought up often enough — in setting up lights for Iray rendering, there's no such thing as One True Setting™ that "just works" no matter what your scene is; every scene is different, and every time you set up a scene you will have to experiment and tweak until you get light settings that work well with that scene.
That's equally true for " People either don't know or forget that Exposure Value needs to be set for every scene.". You can adjust the lighting, adjust Tone Mapping, or adjust both. Tone mapping by itself will only affect the look of the image. It won't impact render speed or the amount of grain in the render. It's also "brute force" since it impacts the entire scene rather than selective areas.
Might be an old thread but OMG what a brilliant one! I was going nuts over the same issue, I was sort of on the right track as I kept fiddling with the camera F stop, to know avail, after reading about the Tone Mapping and diving in I have a whole world of light opening up. Many thanks.
@middle_watch "reading about the Tone Mapping and diving in I have a whole world of light opening up"
Why don't you just make the lighting brighter or add more photometric lights? The scene will generally render faster with more light. Don't get hung up on using "real world" lumen values.
Here's the thing to consider about the tone mapper: there are maybe 10-12 stops of dynamic range between a regular PNG, JPG, or TIF file, and the image created internally by Iray. If you're familiar with tone mapping in a program like Photoshop the concept is the same. If you start out with a high dynamic 32-bit (per color) image, you pick the tonal range you want to use -- either the dark end, the bright end, or something in the middle. When you use the tone mapper in Iray you're doing much the same in adjusting an 8-bit range of values over the 32-bits of the image being created internally.
You can access this 32-bit high-dynamic uimage by turning on the Canvas feature, and opting to do a Beauty render. When you save the image you'll get an EXR file along plus the 8-bit file in the format you selected.
I'm not really saying you need to go through all this hoopla to get a good image, just that messing with the tone mapping settings isn't really doing anything for you that increasing the light values wouldn't do, and would make life easier. The caution about getting hung up on lumens is a good one. Lumens involves the area of the emitter, and often this is not considered.
Tonemapping in post for the win.
Tonemapping is something I have never even looked at yet (I'm still new) I just played with it and wow, it answers lots of my questions now about why I had lighting issues in the past. I have been using some presets I bought to get proper lighting control but of course doing only that limits me to the PA's vision and isn't always flexible.
I probably would have known if I would just read the manual, but hey... who reads the manual right?
;p