Exposure slider

[danio]

I find myself starting to get a bit lazy when it comes to adjusting camera exposure and I’m starting to rely on the exposure slider in the ‘Color Corrections’ extension of the VFB to darken or brighten slightly maladjusted scenes. Is there any downside to this? Do you end up not having data that you would have otherwise? Is there a cutoff point?

Cheers,

Dan

[vlado]

V-Ray is better able to sample the scene if it knows the final exposure, at least approximately. With that said, doing small adjustments afterwards is perfectly ok, especially with the progressive sampler where by default the whole image is sampled uniformly. In fact we are moving even more color-mapping settings to the VFB, like the burn value etc, and at some point V-Ray will be able to read those settings and adjust the sampling for next render accordingly.

Best regards,
Vlado

[AlexP]

On the subject of the exposure slider.
If I’ve made some adjusments using the slider, but now want to put those adjusments into the camera, how do the numbers on the slider relate to the camera settings?

[vlado]

@alexyork

On the subject of the exposure slider. If I’ve made some adjusments using the slider, but now want to put those adjusments into the camera, how do the numbers on the slider relate to the camera settings?

One way is to multiply the ISO value by 2 raised to the exposure value.

Best regards,
Vlado

[Morne]

@alexyork

On the subject of the exposure slider.
If I’ve made some adjusments using the slider, but now want to put those adjusments into the camera, how do the numbers on the slider relate to the camera settings?

For us it seems to work like so:
If you’re slider is +1, then whatever your shutter is (lets say it was 200), it is then halfed to 100
If your slider is -1, then your shutter will be 400

So to simplify
if shutter is 200
+ = devide
- = multiply
forget the ± on the slider:
slider +1 = shutter / (slider x 2) = 100
slider -1 = shutter x (slider x 2) = 400
slider +2.5 = shutter / (slider x 2) = 40
slider -3.07 = shutter x (slider x 2) = 1228

[AlexP]

@fpedrogo

For us it seems to work like so:
If you’re slider is +1, then whatever your shutter is (lets say it was 200), it is then halfed to 100
If your slider is -1, then your shutter will be 400

So to simplify
if shutter is 200
+ = devide
- = multiply
forget the ± on the slider:
slider +1 = shutter / (slider x 2) = 100
slider -1 = shutter x (slider x 2) = 400
slider +2.5 = shutter / (slider x 2) = 40
slider -3.07 = shutter x (slider x 2) = 1228

This was a bit off still when i tried it, but using vlados equation worked (thanks).

So : ISO x (2^slider) is that right? seemed to work at least

Any chance we could get a button to transfer the exposure slider adjustments to the current camera?

[vlado]

@Guest

Any chance we could get a button to transfer the exposure slider adjustments to the current camera?

Yes, will make a note for it. Initially I thought this could be automatic, but there are complications (e.g. if you have multiple cameras, or if you don’t really want to change the camera etc).

Best regards,
Vlado

[eyepiz]

@lzmihich

One way is to multiply the ISO value by 2 raised to the exposure value.

Best regards,
Vlado

Can someone give me an example? Lets say my ISO is 100 and my VFB Exposure is -0.17

[svetlozar.draganov]

Iso=88.88=100*(2^(-0.17))

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