# Default exposure value of VRayPhysicalCamera when exposure is disabled?

**URL:** <https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579>\
**Category:** General\
**Created:** [July 29, 2014, 3:58am UTC](https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579 "2014-07-29T03:58:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![RockinAkin](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/rockinakin/32/21889_2.png) [@RockinAkin](https://forums.chaos.com/u/RockinAkin)\
**Post date:** [July 29, 2014, 3:58am UTC](https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579/1 "2014-07-29T03:58:30Z")

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If I render through a VRayPhysicalCamera with exposure disabled (or a 3ds Max Viewport / 3ds Max Camera for that matter) - what is the default Exposure Value (EV) it defaults to?

In other words:  
What F-Stop, Shutter Speed, and ISO values do I have to set for a VRayPhysicalCamera with exposure **enabled** to get the same exposure value of a camera with exposure **disabled** entirely?

Hope that makes sense - Thanks!

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**Author:** ![vlado](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vlado](https://forums.chaos.com/u/vlado)\
**Post date:** [July 29, 2014, 7:25am UTC](https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579/2 "2014-07-29T07:25:20Z")

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Not sure right away, I have to look at how the math comes out.

Best regards,  
Vlado

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<div class="post-metadata">

**Author:** ![RockinAkin](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/rockinakin/32/21889_2.png) [@RockinAkin](https://forums.chaos.com/u/RockinAkin)\
**Post date:** [July 30, 2014, 6:54am UTC](https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579/3 "2014-07-30T06:54:45Z")

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Cool, thanks for looking into it Vlado!

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**Author:** ![\_Lele](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/_lele/32/49986_2.png) [@\_Lele](https://forums.chaos.com/u/_Lele)\
**Post date:** [August 2, 2014, 12:16pm UTC](https://forums.chaos.com/t/default-exposure-value-of-vrayphysicalcamera-when-exposure-is-disabled/50579/4 "2014-08-02T12:16:56Z")

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i am.  
all to defaults, set isos to 3225.

Simple test, really: set the BG to white 1.0, render with your exposure on, colorpick the resulting value (with default settings, 0.031).  
Your ISOs will have to be multiplied by 1/picked value, or 1/0031, or 32.25.  
So 100\*32.25 will give you the value above, and a 1.000 float value in viewport.

In fact, the closest value (due to rounding errors) is 3218 ISOs.

EDIT: Setting the bg to a 1.000.000 float white, to cut on rounding errors, i found the ideal value to be 3217 (well, 3216.99, but you get the gist.)