32-bit floating point HDR support for LR4.1 RC2 (Cross-posted from the LR forum)

[Schewe]

Folks,
 
In the event you haven't discovered it, LR4.1 RC2 has added support for importing and adjusting a 32-bit floating point TIFF file. Which means LR4 can tonemap an HDR image. To use this, you'll need to use Photoshop's HDR Pro to put together the multiple exposed images, then set the options to make a 32-bit HDR image in HDR Pro and save that as a TIFF file. Then import the TIFF into LR4.1 RC2 for toning...note: nothing you do to the HRD in HDR Pro will impact the 32-bit FP TIFF. If you do some initial adjustments of the original raw files in LR 4.1, I'm pretty sure most of the toning in LR4.1 on the raw files is ignored. But white balance works (haven't tested spot healing and lens corrections yet).
 
Note, to do the HDR process, the raw images will end up being demosaiced and the saved HDR TIFF will be a linear ProPhoto RGB image.
 
Try it...the ability to use LR (and eventually ACR–it's not hooked up in the ACR 7 beta yet) to toning HDR images is actually pretty impressive. Also note, that you don't really need to feed HDR Pro a ton of multiple exposures...2 (normal and under to preserve highlight detail) or 3-5 depending on the scene contrast range is all you need. More isn't really better (unless you really need to shoot a very high dynamic range scene...

[Tony Jay]

Thanks Schewe

I will certainly be giving it a go.

Regards

Tony Jay

[Robert-Peter Westphal]

Hi Jeff,

that sounds very interesting !

Does that mean that I can use any HDR-software to align the shots and create a 32bit file, reimport it into Lr 4RC2 as a 32bit TIFF and process and keep the file in 32bit until I export or print it ?

Does Lr show a histogram of the 32bit values ? How can I see how the picture will look when going to 16bit without really going to 16bit ( i.e. prior to printing).


Will Adobe in the way you see ti put the aligning and primary 32bit creation part also into Lr so it will be possible to create complete HDR-files without the help of any different software than Lr ?

Robert

[aduke]

I would like see a 32-bit option in the Export dialog so that I can send 32-bit images to any application that will take them.

Alan

[Robert55]

Looks very nice, I've tried on a couple of series only so far, which leads to a couple of questions. (I'm using PS CS5 BTW).

- like with merging to panorama, I get a pop-up that this function MAY require the use of ACR 7.1. Does this mean that the actual conversion is done by PS, in PV2010? Does this actually make a difference here?

- I can then go straight for the conversion to a 32 bit TIFF, without doing any toning [as all of that can be done in LR]?
- or is it better to do basic toning in HDRpro, convert to PS and go back in History to the state were color profile was assigned?

- now here comes the part I don't like, but maybe I'm doing it wrong. Saving a merged pano puts in the folder were the base images are [after suggesting a name derived from the first image used] and also imports it into LR (bypassing the import dialogue, it shows up in Libary directly). With the HDR all of this does not happen: saving is in the directory last used by PS, using a generic name, HDR2.tif or something. Is there a way to avoid this?

[Schewe]

- I can then go straight for the conversion to a 32 bit TIFF, without doing any toning [as all of that can be done in LR]?
- or is it better to do basic toning in HDRpro, convert to PS and go back in History to the state were color profile was assigned?

You want to simply save out the 32-bit TIFF. When you select the 32-bit option, you don't really have the ability to do any toning. You can change the gamma slider but I'm pretty sure that only impacts the file preview and don't actually impact the full 32-bit rendered file.

As far as the LR4>CS5, you'll want LR4 to do the render.

With regards to your complaint regarding LR4>CS5 popping a a new saved TIFF from Edit In, yes, that's what happens with your LR and ACR versions are out of phase. When out of phase you have to have LR render the file and this requires saving a TIFF prior to LR handing the file off to Photoshop. When in phase, LR just hands off the file to ACR to render and a TIFF file isn't saved. But, I don't thing that apples to HDR Pro...and yes, Photoshop insert a default name and save in the last folder.

As far as working with 32-bit in CS5, can't really tell ya since I'm using the CS6 beta.