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Lately I've been posting Pictures on this forum and 1 or 2 times now I've received a comment on how the background of my rendering through the window should be more over exposed.

Leonardo wrote:the leather bump seems off... too big, to intensive

Also, your background should be more over-expossed almost wite, if you'e after photo-realism


..oh, BTW, It looks great!
leo

Thanks for the comments I truly appriciate them.

What I'm getting at is not photorealism but Realism
In photography the aperatus of the camera can only display one exposure at one time, Where as the eye reveals all exposures at the same time. This phenom is called Dynamic range.
Here is something to try right now as you're reading this.....look around the room and find a window. Look out the window......Notice how the interior of the room is not underexposed to the eye like it would be in a Photograph? Now try the oposite. Look around the room to the left or the right of the window......Notice how the scenery outside is not overexpposed like it would be in a photograph? This is because God created the human eye to capture the full dynamic range of the scene you are looking at where as a camera is only a machine. The Camera industry is just starting to realize that photographs are not realistic and are developing ways around this
I have developed a way of Creating a high dynamic range renderings with Maxwell Render's cameras. Which is another post for another day.


My point is that Leo was right when he said:

Leonardo wrote: Also, your background should be more over-expossed almost white, if you'e after photo-realism

..oh, BTW, It looks great!
leo

But what I'm humbly sugesting is that my renderings are more realistic than Maxwell's Native output can produce. The question that does remain is this:

Do you like them Photorealistic (a real photo) or Realistic (as in real life)?

Best regards
Chris

I 'm agree with your realistic approach. This remind me some HDR photo that i saw last week on Flickr (http://www.flickr.com/groups/hdr/). This technics bring, as you said, a realistics vision of the subject. But our photographic culture tend to see the HDR photo as fake.

Different website that show some result of HDR photo:
http://www.hdrsoft.com/
http://www.cambridgeincolour.com/tutori ... -range.htm
http://www.i-marco.nl/weblog/archive/20 ... hotography

All OK but I think you're missing a point. It's also related to how you view the images. On screen? On paper? Your monitor is not capable of displaying the images in HDR, no? (there are expensive HDR monitors but this is another subject) ...and on the paper it's the same. You cannot distinguish a bright white cloth from bright white light coming off from window if your output devices are not capable of triggering your retina with the needed high range intensity per pixel. So what? It's quite normal seeing them unrealistic when you normalize down the high dynamic range into a LDR display because the contrast is lost.

I think that if you were doing some type of VR environment, where you wanted your client to actually experience being in the room, then you would want real real as perceived directly by the human eye.

From the perspective of an architectural visualizer, I try to have my images coorespond to what I think a good architectural photographer would produce. Depending on what the view out of the window actually is, and what the focus of the shot is supposed to be, the photographer may choose take multiple exposures to allow a more balanced representation of the view. If the view is not so nice, or the focus is meant to be on the interior (and relating it to the exterior is not beneficial for whatever reason), allowing the view to be over-exposed can take focus off.

I fully realize this and That's all well and good Tom...but the point is do you want see what is real or what a photo can only capture.
The way you achieve realism on a monitor or on paper is via this method. I created High Dynamic Range Image and then I "merged" it down to a LDR image (low dynamic range) so that you can see it on a monitor or paper. The only thing you loose is some luminance and contrast.
This method will fail to make your eyes squint when bright light is being represented on the monitor or paper but the colors and detail in the shadows and highlights are adequately represented, where as before they were over or under exposed.

Here is an example of a photo i took with a real camera (not maxwell ) The endresult is aceptable but its not what the eye sees in real life. (LDR)


And Here is the same Photo in HDR (Closer to what the eye sees)


Best regards
Chris

This is what I'm trying to say. The second one is strictly NOT what we actually see in real life. It's a compressed range (we have this in Maxwell called as "AutoRange") and it's normal that would look truly bad about contrast. You said "Closer to..." but it's 10 miles away in terms of perception because the contrast range is off. HDR images are not for viewing with our monitors, nor printable you know. You can make image based illumination with them or you can extract different LDR ranges from them or you can view them on a HDR display. But trying to bring full range into LDR will completely mess the thing up.

Hi Chris,

Isn't the second image closer to what would happen if you lower the "burn" value, in tonesmapping, to something low (like 0.2 or 1.0 or so) ?

Since I have an ordinary LDR monitor, I would prefer viewing Exposure & Gamma based conversion. Highlight compressed conversion doesn't mean it's the real thing and I don't agree with the web sites in hyltom's links. Our contrast perception is not linear and I don't think such conversion ramp has valuable artistic use.

tom wrote:This is what I'm trying to say. The second one is strictly NOT what we actually see in real life. It's a compressed range (we have this in Maxwell called as "AutoRange") and it's normal that would look truly bad about contrast. You said "Closer to..." but it's 10 miles away in terms of perception because the contrast range is off. HDR images are not for viewing with our monitors, nor printable you know. You can make image based illumination with them or you can extract different LDR ranges from them or you can view them on a HDR display. But trying to bring full range into LDR will completely mess the thing up.

I'm not really convinced by your argument Tom. It's not that i like the HDR photo, but i try to understand what's the best (realistic) outlook. Since around 25 years, i' m used to look some "normal" photo which show highlight and high contrasted area but is it really what my eyes see in real? They are not working like a camera and are not as sensible to light as a camera sensor. Take for example the picture that you post. If you were in this apartment and look in direction of the window, what will be you perception? I don't think your eyes will be blind by outside light but for sure they will be by the lamp (depending of its intensity), so for me this example is not well done.
The problem with HDR photo is that it's like doing some painting of what you perceive to be real, so it's base on the artist eyesight.

No, you misunderstand my point. I don't say we see the things overexposed and in LDR. It's technically correct we see a wide range but HVS works quite different. It has particularly different exposure compensation per retina cone and a complicated image processing/merging system in the brain. It's not that easy converting a high white compressed HDR into LDR and say this is in fact how we perceive this. When you look inside the room, you wouldn't notice the detail in the window and perceive it as something very bright but when you focus to window itself it will become clearer and so on. These peeks are collected into one full image that we think we perceive at once.

To follow what i said earlier, here is an example of a painting done in 1739.



Naturally, the artist (Francois Boucher) had painted the windows area as he saw it, nothing is burned. So, i' m still thinking that the actual camera output have distorted our perception of light.

Right, but that looks like a painting. The problem with using a balanced exposure in a render is that it doesn't look like a photo that way, but everything else in the picture does. So instead of looking "more real" it looks less real, because it doesn't meet our expectations. There's just something perceptually not quite right about it, even if most non-experts wouldn't be able to identify what it is. The problem is that when we look at something that looks like a photo, we expect it to look like all the other photos we've ever seen. That's why tonemapped HDR photos look less real than LDR photos, even though you might be able to objectively say they more accurately depict the scene and contain more information.

superbad wrote:Right, but that looks like a painting. The problem with using a balanced exposure in a render is that it doesn't look like a photo that way, but everything else in the picture does. So instead of looking "more real" it looks less real, because it doesn't meet our expectations. There's just something perceptually not quite right about it, even if most non-experts wouldn't be able to identify what it is. The problem is that when we look at something that looks like a photo, we expect it to look like all the other photos we've ever seen. That's why tonemapped HDR photos look less real than LDR photos, even though you might be able to objectively say they more accurately depict the scene and contain more information.

Well, it's a painting . But it's also the first way to attend to copy reality. At that time, their vision was not deteriorated by photo knowledge. They painted what they saw, but of course the painting technics was a constraint to reproduce reality. Now our modern technology allow us to give to photo another dimension. This looks fake now, because of the wrong perception that "old" photo give us and that we are used to it. But what will happen to this feeling after 10 or 20 years of HDR photo use. At that time, your reaction will be, why the windows is completly burned?...what a bad photo!

Hyltom, don't forget the fact that the actual painter did not paint the entire canvas in one single jet... when he painted the window, his eyes focused the window,... and so on....

this is why each part of this painting is right exposed...

I believe to re-create this effect.. you'll have to blend + cut different renders at different exposures... very different than simply blending thefull entire range of pictures..

BTW, I can over-expose or underexpose with my own eyes (you need to train a little, but that hurst a bit..)

example. you are in a close room with a mini window... and you lok not exactly in the direction of that window... well outside is over-exposed... same thing if you concentrate your view on the window... the room become very dark...

just my 2 cents..

edit... we should be looking at PHOTO- realism using Maxwell, because EYES-realism would require stereo image anyway... besides, people are used to it...

Hervé wrote:blend + cut different renders at different exposures...

This is HDR Photo and what i'm talking about and also what Chrisnvp has done in his picture.

Hervé wrote:blending thefull entire range of pictures...

This is HDRi and need as tom said and HDR display or paper.