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How to control contrast/glare in HDRI


thanulee
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Hi, i was wondering how to achieve this http://jeffpatton.net/2012/09/mixing-render-engine-features/

 

This is raw rendering with vray lens effects. If u notice on the horizon line the color is very orange-yellow and gradually goes to overexposed white. Its like the HDRI has alot of contrast without getting overexposed at the bottom.. Or even on top left is kinda blue and not over exposed! I did some tests with Peter Gunthrie's hdri maps which are the best i ve used so far but still i cant even near achieve this result.

 

Is there anyway to control contrast on HDRI without over exposing it? thank u

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If you are using vray I guess you can load the hdri in the VrayHDRI map and adjust the contrast by changing the gamma value. Do not confuse this with the regular gamma setting. And therefore adjust color mapping settings so it won't get over expodes.

 

You can also change the hdri image manually in Photoshop.

 

Maybe you already knew all this, it would be kinda interesting to here what you already tried so we don't give you old news.

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Heya, yes im using vray. Well the gamma option gives me higher constrast, but it overexposes the image greatly. I mean even with gamma 1.0 and not even less (less gives contrast) the image is overexposed already at the edges. His image is overexposed only at the sun place. Ya i tried that, with exponential color mapping and didnt work either. I have no idea how he gets that result :p Check this pic also:

 

The highlights on the pavement is a very nice burn yellow. This is the overall hue tha jeff patton has on the first picture i posted on its bottom side! I didnt try mess up with the hdri at photoshop.. maybe i would do that? thanx

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lol, yea u are right about the pavement, i just woke up!

Well clamp output doesnt affect hdri almost at all... check these renders out. Doesnt seem to work. I cant control contrast without affecting overall lighting and reducing the huge hotspot. Which is most likely physically correct right? I cant even get near to getting that nice burn yellow! Any other suggestions? thanks man!

 

ps. imagine that i want even lower gamma to achieve proper lighting -> thus huge hotspot!

gamma 1.5.jpg

default gamma1.0.jpg

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Ok, I know you tried experimenting with exponential, but did your experiment with the bright value? Try Reinhard and lower the burn value to 0,25 or something similar. Depening on which version of vray you use you can increase the output omount in the VrayHDRI map. Default value is 1.0, maybe you can try 1.5

 

He uses the Vray Lens effect. Turn on bloom and glare. In this case I also think you must turn on DoF and Bokeh in your physical camera settings, as well as specify focus and focus distance. And ofcourse if you need to lower the f-number to get that DoF you're looking for. When lowering the f-number you need to adjust the ISO and/or shutter speed to balance the exposure.

 

For final contrast control adjust the curves in vray frame buffer.

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Let's see.

 

Color mapping

Type: Reinhard

Burn value: 0,15

Gamma: 2,2.

Only affect background is ticked.

 

VrayHDRI

Multiplier: 1

Gamma: 0,8

Output - Output Amount 1.5

 

Camera

F-number: 3

Specify focus is on

Focus distance: aprox 2 meters

White balance: Neutral

Shutter speed: 3000

ISO 100

Bokeh effect is on with 8 blades

DoF is on.

 

Environment and effects

Vray Lens effect

Bloom and glare, play around with the values you prefer.

 

Vray frame buffer has a color curve correction which enhances the contrast.

 

My vraylight dome has a multiplier of 1.

 

I guess thats all.

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Actually can u send me ur file somehow? i m starting to think that max 14 has something wrong xD I get overexposure still with ur settings...I just wanna render urs as it is to see if images match.. I hate 3d studio when acts like this for real :/

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