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Author Topic: Does Helicon Focus support 32 bit images  (Read 1473 times)
texshooter
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« on: July 29, 2012, 01:37:09 PM »
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Im told that HDR processed images that are tone mapped in Photomatix are delivered in 32 bit format, compared with 16 bit delivered by the exposure enfusion process such as EnfuseGUI.

if i were to upload 32 bit images into Helicon Focus, would it handle the 32 bit files for focus stacking.

I want to make HDR focus stacked Panoramas. Ive been advised that the best sequence is

First.      HDR exposure bracketing (Photomatix, EnfuseGUI)
second.  stack focusing. (Helicon Focus)
third.     panorama stitching (PTGUI, etc)

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texshooter
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« Reply #1 on: July 29, 2012, 05:36:00 PM »
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I just read this from the Helicon website:

"Helicon Focus supports JPEG, TIFF, BMP, PSD and various RAW formats with 8 and 16 bits per channel."

So that answers that question, but I wonder if there is a focus stacking software that supports 32 bit per channel formats. I know I can always stack focus my shots in Helicon focus BEFORE doing HDR work on them in Photomatix, but I read somewhere that this is not good.
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milt
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« Reply #2 on: July 30, 2012, 08:13:10 AM »
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Once you have done the HDR processing, why do you think a 32-bit representation will be necessary/helpful?

--Milt--
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texshooter
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« Reply #3 on: July 30, 2012, 03:57:27 PM »
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why do you think a 32-bit representation will be necessary/helpful?

I've been told that tone-mapping before stitching can cause artifacting and stitching errors, depending on the tonal makeup of the scene. Because my display, and I suspect everyone else's display can show 32-bit depth images, I don't see any good reason to tonemap the HDR files (which will compress them to 16-bit files) BEFORE completing all the editing I want to do with them(i.e. focus stacking and panorama stitching).

The problem is that for HDR+Focus stacking+panorma projects (I get the feeling no one on earth does this), focus stacking software, such as Helicon, do no take 32-bit files. This throws a wrench in my planned workflow. I haven't actually tried this stuff, by the way, but am researching for the optimal workflow and tools to use. It's a bit complicated to say the least.
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bill t.
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« Reply #4 on: July 30, 2012, 10:27:21 PM »
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I do focus-stacked, hdr panos all the time.

For each panel in the pano, I shoot an hdr set at each focus plane, then move on to the next plane.  I Lightroom the raws into 16/component tifs.  I process the individual hdr stacks, usually with a batch process.  I run the processed hdr images through Helicon for focus staking, being sure to manually edit moving clouds with Helicon's Retouch tool if needed.  Then I stitch.  Always works just fine.  The only thing I know of that absolutely creates artifacts is if I try to stitch before running hdr or focus staking.

One must remember that all that hdr and focus stacking will take slight toll on image quality.  One needs to find a balance between how much is applied versus the realistic requirements of the image.   I doubt if you can effectively retain the full value of even 16 bit/component files through the whole process, even in the best of circumstances.
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texshooter
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« Reply #5 on: July 30, 2012, 11:32:11 PM »
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I run the processed hdr images through Helicon for focus staking,

So it sounds like you tone map (compress from 32 bit to 16 bit) BEFORE you import into Helicon. That surely is doable, but I suspect you are losing quality by clipping all those floating bits before you finish all your processing. At this point I don't think there is another option because Helicon does not accept 32 bit files (for now, anyway). I'm assuming, of course, that your processed HDR images are tone mapped instead of "exposure enfused."  I believe "exposure fusion" renders 16 bit files (not 32), in which case you never have to worry about a thing.

Side bar: What does an HDR image look like before it is tone mapped? I've read in numerous places that a pre-tone mapped HDR image can not be viewed on a display (hense the need for tone mapping). I don't get that, because my display shows 32 bit color channel. I have the option of reducing the display range to 16 bits, but I leave it at 32. So I don't understand why Photomatix has this thing called an "HDR Viewer." Unless most people use 16 bit monitors.
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bill t.
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« Reply #6 on: July 31, 2012, 12:06:53 AM »
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Just start doing it.  For the first few panos, forget the tech stuff entirely, simply go for some result however imperfect.  It will all make sense after the first few exercises.  Nothing is more informative than the perspective that comes from actual experience.

On screens of every description all the unmapped hdr files I have viewed have been represented like a regular file with brightness and contrast max'd out.

No matter how many "bits" a monitor may have, they all pretty much have the same brightness range, which on a calibrated monitor is typically a few hundred to 1.  Larger monitor bit counts simply adds more gradation, not more dynamic range between bright and dark.  And in most if not all cases, hyper-fine monitor gradation will not affect image appearance.  Also, most cameras are hard pressed to give you 14 to 16 bits in each channel, and the fine bits are rather noisy in the best of cases.  That puts an upper limit on the bit resolution that is meaningful to carry through post.  And like it or not, most printers are limited to 8 bits, maybe a few can handle 15 or 16.

And yes, with every additional technical step you lose quality.  Don't use hdr unless it will make the image better.  Only focus stack when you need to.  Compromises are involved, on an image by image basis one must decide whether a certain level of post work will give you a better image, or merely the fun of spinning one's techno gears at the expense of the final result.

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