Does LR HDR Merge require centered exposures?

[dwswager]

What I am asking is does Lr assume the center point of exposure is supposed to be middle tone?

I've done lots of HDR with other programs and lots of times I will have a 1st exposure that captures all but the highlights.  I will then shoot a 2 or 3 more frames, usually 2 stops less exposure each to get the highlights captured. When I merge to HDR using LR, the resulting image generally is dark overall and requires -100 on the Highlights slider to bring the highlights into range.   And, of course, because the image is dark, the Exposure and Shadow sliders get a workout.

Should I shoot 2 or 3 additional frames with more exposure to balance this out for LR.  It would be a nice feature addition if we could set an overall exposure bias for HDR merges.

[Paul2660]

LR's HDR mode has always seemed a bit strange to me, for the same reasons, as I tend to expose the same, -2 - and +2 or even -3 0 +3.  No matter the HDR merge tends to be very light, very occasionally highlights are blown, but not often. 

The end result is not what you expect, but once you start using some local adjustments, the files become very nice.  But as you point out, no matter what combination, the base highlights slider will be maxed out, thus you have to use the local adjustments to fine tune the file.

Where I had more trouble, (and posted here about it) was merging several HDR's in to a pano as LR for some reason would tend to blow out the finer highlights, even if they were not blown before.  Not sure if this issue has been addressed or not as I have tried a sunset pano in a while.

Paul C

[ErikKaffehr]

Hi,

My understading and experience says LR's HDR works well with just two images unless ghost elimination is needed.

Best regards
Erik

What I am asking is does Lr assume the center point of exposure is supposed to be middle tone?

I've done lots of HDR with other programs and lots of times I will have a 1st exposure that captures all but the highlights.  I will then shoot a 2 or 3 more frames, usually 2 stops less exposure each to get the highlights captured. When I merge to HDR using LR, the resulting image generally is dark overall and requires -100 on the Highlights slider to bring the highlights into range.   And, of course, because the image is dark, the Exposure and Shadow sliders get a workout.

Should I shoot 2 or 3 additional frames with more exposure to balance this out for LR.  It would be a nice feature addition if we could set an overall exposure bias for HDR merges.

[dwswager]

Hi,

My understading and experience says LR's HDR works well with just two images unless ghost elimination is needed.

Best regards
Erik

So shoot one exposure to get the shadows captured without clipping and a 2nd to get the highlights captured without clipping?

Some programs like multiple shots, but want them at consistent stop spread.  My real problem wasn't landscapes that tend to be somewhat more naturally "centered", but indoor room shots where a single exposure captures the entire inside, but the outside (of windows) may be 4 to 7 stops higher.

[ErikKaffehr]

Hi,

A baseline exposure and one to protect highlights, but I seldom do that kind of stuff...

Best regards
Erik

So shoot one exposure to get the shadows captured without clipping and a 2nd to get the highlights captured without clipping?

[RikkFlohr]

According to the engineering team - if your two exposures are three or less stops apart, (ie 0, -1.5, +1.5), a third exposure is not needed. In this case, merging the -1.5 and the +1.5 and ignoring the 0 should give you as good or better results than using all three exposures. See the guide below.

Under to Over - Optimum number of exposures for PhotoMerge to HDR in Lightroom:

Up to:
-1.5 to 1.5 = 2 exposure
-3.0 to 3.0 = 3 exposure
-4.5 to 4.5 = 4 exposure
-6.0 to 6.0 = 5 exposure

[rdonson]

Thanks, Rikk!!!

[dwswager]

According to the engineering team - if your two exposures are three or less stops apart, (ie 0, -1.5, +1.5), a third exposure is not needed. In this case, merging the -1.5 and the +1.5 and ignoring the 0 should give you as good or better results than using all three exposures. See the guide below.

Under to Over - Optimum number of exposures for PhotoMerge to HDR in Lightroom:

Up to:
-1.5 to 1.5 = 2 exposure
-3.0 to 3.0 = 3 exposure
-4.5 to 4.5 = 4 exposure
-6.0 to 6.0 = 5 exposure

Great information.  Does the engineering team have anything to say about getting the overall tonality close?  Obviously, you don't want to move tone across each other, but if the bulk of tones are at -3.5 and it takes +4.5 to capture the highlights there seems no leeway to adjust overall tonality of the HDR DNG with out pushing the blacks and whites over the edge. 

What would be extremely useful, at least to me, would be a gamma slider in the HDR Merge dialog box to the overall tonality of the resulting DNG file while holding the blacks and whites.  Then when it dumps it out to the regular develop modules, the controls have the movement left.

[Rory]

What would be extremely useful, at least to me, would be a gamma slider in the HDR Merge dialog box to the overall tonality of the resulting DNG file while holding the blacks and whites.  Then when it dumps it out to the regular develop modules, the controls have the movement left.

I have not used the HDR recently, but reading this made me think about a work-around for you.  In addition to the basic controls, have you tried using the tone curve in point mode?

[dwswager]

I have not used the HDR recently, but reading this made me think about a work-around for you.  In addition to the basic controls, have you tried using the tone curve in point mode?

No I had not, and good point.  I've become somewhat lazy with all the controls in ACR and Lr.  While I still think it would be useful to be able to alter the overall tonality written into the DNG this may prove a suitable solution.

[luxborealis]

No one has mentioned toggling OFF Auto Tone in the HDR Merge panel. If you are leaving it on, try turning it off. I've had much better success with the few ZHDR blends I've done by starting with no auto tone.

[Paul2660]

Exactly, by tuning off auto tone, most times you will have much more image to work with, and the main sliders have not been maxed out.

Paul C

[dwswager]

Exactly, by tuning off auto tone, most times you will have much more image to work with, and the main sliders have not been maxed out.

Paul C

While this is true in the strictest sense, you still maxed out the sliders to get back to where auto tone would have them.  My point still remains that we need a midpoint set point in the settings to tell the HDR Merge this is what I'm looking for so use this as the basis for merging the exposures.  It could be a slider that allows gross adjustment of tone, within the limits of the data, for LR or ACR to execute the merge.

[luxborealis]

While this is true in the strictest sense, you still maxed out the sliders to get back to where auto tone would have them.  My point still remains that we need a midpoint set point in the settings to tell the HDR Merge this is what I'm looking for so use this as the basis for merging the exposures.  It could be a slider that allows gross adjustment of tone, within the limits of the data, for LR or ACR to execute the merge.

I'm confused. How would a "midpoint" file tell LR "This is what I'm looking for"? I understand it in theory, but in reality it's nothing like what I'm looking for when doing an HDR blend.

Maybe I'm ignorant about how far HDR has come, but do you think LR is "smart enough" to understand the middle tones of one exposure are the ones you want to maintain? If it is then I'm impressed and would say it really should have a clear declaration to make a "middle-tone" exposure in addition to the "–" and the "+" exposure, which it only does for wider spreads (thanks Rikk).