sRGB ruining our renders?



  • have a look at this video.



  • Long time ago it was one of main reason why I experimented a lot with Luxrender. Why I bought Octane. EXR->Picturenaut (or Photoshop or Krita or anything else where you can play with tonemapping). Still can not understand the reason why P11/Superfly doesn't have tonemapping at all. Even simple exposure and whitepoint control.


  • Poser Ambassadors

    @ghostship So how to fix this in Poser?



  • @Ghostman I think it would take the Poser team incorporating a way to include the fix they use in Blender.


  • Poser Ambassadors

    @ghostship Not gonna happend until P12 then I guess.



  • If at all, as that is part of Blender, not Cycles. And this is feature, not fix.
    Poser needs OCIO integration for this.
    I hope P12 will have at least some tonemapping options.



  • Doesn't Tone Mapping help with this, more accurately simulating light levels and "film?" I've experimented with it a bit and the effects can be quite dramatic. (Though, I could really use some tips for Tone Mapping and the like... hint hint...)



  • heh I was having an issue with room illumination with sunlight and comparable results to what I see in my photography. Well damn, now I know why.

    I don't seem to have this issue in Lux though, maybe it doesn't use sRGB... I dunno.



  • Yeah I watched this Ghost. But doesn't Poser have a wide range of fstops and HDR output?



  • I ran into the same issues when converting Poser lights to camera numbers (exposure/fstops) for my lighting tutorial. Poser renderer does not have a wide dynamic range at all. Although I had assumed it was better than a basic camera, turns out it is slightly worse than Blender.
    Measuring in f/stops is a logarithmic progression, meaning as you go up by one, the value doubles. So, one stop more exposure doubles the available light, 2 stops is 4 times the available light. As you increase light levels you expect detail to wash out. The problem described in the video (and in fact on the majority of threads on this topic relating to dSLR's) is that the theoretical/calculated dynamic range is broader than the functional dynamic range, the functional range being what you can discern from the image by actually looking at it.

    The image below is a modification of my standard "18% grey", 2 squares are RGB127 in all channels, the other is white (255) and black (0). It is correctly 'exposed' so that the light returns exactly RGB127 on the grey squares.

    0_1487474174834_base dyn range.jpg

    Now you need to increase the light until the grey washes out and is hard to separate from the white. At that point, you have reached the maximum dynamic range in one direction.

    0_1487474322287_2 stops.jpg

    This image is 2 stops up, so 4 times the light. Grey is still clear enough, but we are already getting close to the edge of the range. The absolute high range seems to be around 2.1 stops high as the render below illustrates. The grey squares are just visible.

    0_1487474753007_2.1 stops.jpg

    So what about the other direction? Well, Poser does well in that direction with Superfly, a massive 8 stops down and the squares are still clearly defined (1/256th of the light and you can still see). Poser will give very good definition in shadows...perhaps too good.

    0_1487475589710_8 stops.jpg

    So theoretically you could say Poser has a dynamic range of 11 stops, but on a scale of 1 to 11 if you have to use level 9 to get a normal return then the practical range is much less as the correct exposure level is NOT in the middle of the range.



  • Has anybody brought this up with the Poser Team? I can see how it affects my renders but I don't know enough about it to complain to them about it or request this feature for the next version of Poser.


  • Poser Ambassadors

    @ghostship
    I think it is essentially the same as when you render to EXR, then load the render in Photoshop (or other imaging software) and apply the ASES color settings to the image. (you render in linear color, then apply the color space).

    The problem with this approach is that you render in 32 bit color. Converting this to 16 bit (PNG) or 8 bit (JPG) involves tone mapping. Most web sites require PNG or JPG and automatic tone mapping often brings you back to the same sRGB settings you wanted to avoid.

    I wonder if the method described in the videa also requires saving in 32bit color (EXR or HDR) and gets you into the same problem.

    If your output can handle 32 bit color this works very well.



  • I don't think so. The renders in the video will all render just fine from an 8 bit source, just like a printed picture is essentially 8 bit (you can't make a white page brighter, you can only leave white exposed). It also isn't about the range of tones available. It's about the conversion of exponential intensity values into a linear one.
    To use my images posted above as an example, to get the full 11 stop spread the first image should be in the middle of the range, giving 5 stops above and below. The bright image should be the result 5 stops up, rather than 2 stops, and the dark image should be much darker than it is, and only 5 stops lower not 8.
    So it's about how the renderer distributes the curve. Oh, and I should be calling them exponential, not logarithmic.



  • Simply Poser 11 or Poser 12 if will be,need to have some sort of tonemapping in future because without this is very hard to achieve something like this,but still Poser 11 with SuperFly is nice renderer if you do archviz renders and as above @wimvdb pointed out EXR is great format,export render as EXR,edit in GIMP or any editing SW and you should be OK,agree if this feature is available then we don't need to use at all any photo editing SW

    Will be nice if Poser will offer that,but in meantime

    Thanks,Jura



  • @ghostship "Dear SM, please add tonemapping to Superfly."
    Been here, wrote this.
    May be more voices will do better.

    Minimum: exposure, gamma and white point controls.
    More: + burn highlights crush blacks controls.
    (Not what in video, but in most cases this is enough for stills.)
    More: add variant of adaptive logarithmic tonemapping.
    (Cheaper than filmic film+grading emulation).
    And more: film response curves like in Lux.
    Max: full color management solution. (OCIO and custom LUTs, this is what video about.)



  • We have tone mapping for Firefly in Poser, but Superfly does not have this. My usual approach to this problem is to export the image as EXR and do the tone mappping with Googles free Nik Tools in Photoshop.

    The solution Blender has now is more convinient though. Also, it's "False Color" mode is very convinient to check lighting. In Firefly I would use BagginsBills Light Meter to check the light, but we don't have a comparable tool for Superfly.

    I would be very happy if something similar would be included into Poser. Until then, if you want to work with this problem do your tone mapping outside from Poser. You do have the Possibility to do this.

    By the way, the filters of the Nik Collection work without Photoshop as well. Export your images as EXF and bring light into the dark - and details in the light. The huge disadvantage is that you won't see what you get before exporting and tone mapping the image.



  • @bantha said in sRGB ruining our renders?:

    We have tone mapping for Firefly in Poser, but Superfly does not have this. My usual approach to this problem is to export the image as EXR and do the tone mappping with Googles free Nik Tools in Photoshop.

    The solution Blender has now is more convinient though. Also, it's "False Color" mode is very convinient to check lighting. In Firefly I would use BagginsBills Light Meter to check the light, but we don't have a comparable tool for Superfly.

    I would be very happy if something similar would be included into Poser. Until then, if you want to work with this problem do your tone mapping outside from Poser. You do have the Possibility to do this.

    By the way, the filters of the Nik Collection work without Photoshop as well. Export your images as EXF and bring light into the dark - and details in the light. The huge disadvantage is that you won't see what you get before exporting and tone mapping the image.

    Which of the NIK collection do you open the EXF file in?

    Amanda



  • @bantha downloading this right now. I have CS6 so my fingers are crossed!


  • Poser Ambassadors

    @ghostship said in sRGB ruining our renders?:

    @bantha downloading this right now. I have CS6 so my fingers are crossed!

    Works great in CS6



  • @amethystpendant Do I export as an HDR or open EXR? I can't see an option for EXF.