# How do I change the exposure by exactly 1 or 2 f-stops?



## FutureFocus

My goal is to:

1) Take an existing picture.

2) Make two more copies of it.

3) Alter the exposure compensation of the copies by eitherexactly 1 or 2 stops up or down as needed.

4) Merge those shots to form a quasi-HDR composite image.

When I open the master/source picture in Lightroom, how do Ichange the exposure by exactly one or two stops leaving all of the othersettings untouched?

Yes, I know the master exposure slider goes up to 5.00, butwhat exactly do those values mean if anything in direct correlation tof-stop's? Is it accurate?

Please help me understand how changing the exposure isexecuted.

Thanks in advance.


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## Mark Sirota

Welcome to Lightroom Forums.

Yes, those numbers on the Exposure slider correlate to stops. I think it's the only slider in Develop that actually has units.


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## erro

If you only have one photo, you won't get a true HDR, but you seem to realize that.


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## Allan Olesen

Please note that the exposure slider changes more than just exposure (or rather ISO, but that is another discussion). If you take a photo at -3 EV exposure compensation and another without exposure compensation and set the first to +3 EV exposure in Lightroom, it will not look like the second photo.

Secondly, you already have access to the full dynamic range of the photo in Lightroom. So the trick of exporting with different exposure settings only makes sense if you want to use some other software which:
 - can do something that Lightroom can't
 - can't utilize the full dynamic range of the photo


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## Diko

Allan Olesen said:


> Please note that the exposure slider changes more than just exposure (or rather ISO, but that is another discussion). If you take a photo at -3 EV exposure compensation and another without exposure compensation and set the first to +3 EV exposure in Lightroom, it will not look like the second photo.



@Allan Olesen, could you please elaborate on _what is _the  Exposure in *LR*. To me it never occurred before reading this topic here.  Would love to have a better understanding of this little but important slider.

Thank you in advance.


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## Linwood Ferguson

And in Quick Develop the inner arrow is a third stop, the outer is one stop, so click twice for two.


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## Johan Elzenga

I believe the Exposure slider was changed when Process Version 3 was introduced. It used to be a real exposure slider, that would increase the brightness of all pixels by the same amount. That is no longer the case. It's much more a 'mid tone brightness' slider than a real exposure slider now.


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## Linwood Ferguson

So is there a way to do a across the board increase?   Something in camera calibration?  Or are you saying you can't just have it multiply by 2?   (OK, it's not that simple post conversion, but talking pre)


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## Johan Elzenga

You would probably have to move all five sliders (exposure, whites, highlights, shadows, blacks) or at least three (exposure, blacks, whites), but exactly by how much and whether or not each slider by the same amount I don't know. An easier option might be to set the Process Version back to Version 2. Then a +1 setting of the Exposure slider should be the same as setting a +1 exposure in the camera. I played a little with this and you clearly see the difference in the highlights. Setting a +1 exposure in Process Version 2 clips the highlights significantly more than setting a +1 exposure in Process Version 4.


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## Bruce J

I believe you can also do a straight exposure adjustment in Curves; straight, 45° line, shifted up or down, as needed.


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## Johan Elzenga

Bruce J said:


> I believe you can also do a straight exposure adjustment in Curves; straight, 45° line, shifted up or down, as needed.


Correct, but it would be quite difficult to get an exact +1 stop result, because all you see is some percentage.


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## Bruce J

True, but it still seems easier than fiddling with several sliders.  But, I'm not an expert, so having made my suggestion, I'll bow out.  Cheers.


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## Victoria Bampton

JohanElzenga said:


> Setting a +1 exposure in Process Version 2 clips the highlights significantly more than setting a +1 exposure in Process Version 4.



Yeah, in PV2 it’s a more like +1 on a digital camera with harsh clipping, whereas +1 in PV4 is like more +1 on film, in that it rolls off the highlights gently. 


Sent from my iPad using Tapatalk


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## PhilBurton

Victoria Bampton said:


> Yeah, in PV2 it’s a more like +1 on a digital camera with harsh clipping, whereas +1 in PV4 is like more +1 on film, in that it rolls off the highlights gently.
> 
> 
> Sent from my iPad using Tapatalk


Is there documentation on the differences between the various Process Versions?


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## Victoria Bampton

Nothing that specific. You could go back and compare your older books against newer ones but it’s easier to simply go “life’s moved on”!


Sent from my iPad using Tapatalk


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## Diko

Diko said:


> @Allan Olesen, could you please elaborate on _what is _the  Exposure in *LR*. To me it never occurred before reading this topic here.  Would love to have a better understanding of this little but important slider.
> 
> Thank you in advance.




Allen seems not to be here to answer that question as it seems. Anyways I asked this seemingly simple question due to the export exposure setting primarily.

Here is what I found related to the *discussion *even though it is a little bit old:

_In P.V. 2012 (LR4 and LR5) you cannot equate Exposure slider movements to in-camera exposure changes because the latter is a linear shift of luminosity and LR Exposure is applied on a curve, affecting primarily mid-tones and tapering off at the high end. Moreover, it is not even a fixed and predictable curve, but rather "auto-adaptive", altering the roll-off according to the value of the original white point. In P.V. 2010 (and 2003), however, Exposure was linear and Brightness applied the curve and the option to revert to P.V. 2010 processing does exist in any 2012 edition._

_I'm not very sure how it is in neither of the new LR 7 versions. I doubt that it could be even the same in all versions.  _
Anyways obviously +1 .00 in develop model is actually an increase of 100% of  1 F stop now.


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## Jimmsp

I like Victoria's comment : it’s easier to simply go “life’s moved on”! 
If I have only taken one shot of a well lit scene - then I can do quite well in LR with the sliders I have to work with along with the adjustment brush.
(BTW, the adjustment brush is your friend with shadows and highlights).

If I can't recover some highlights or lift some shadows to suit me, then it is not the fault of LR - it is the "fault" of the camera for having a more limited dynamic range that my eye has. Then, I have the easy ability with today's decent DSLRs to fire off 3 quick shots with + or - 2 stops, and have LR put them together in a true HDR.


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