3 shots from 1- photoshop

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  • #770
    anneb
    Participant

    Hijacked quote from this week’s contest thread:

    Do you shoot RAW? If so, you can create an HDR image from a single RAW file by developing it at different exposures. All of the shots I’ll have this week are done like this. One benefit to using a single RAW file is that you don’t have to worry about aligning the images, because they’ll be exact other than the exposures. If you want to try this method, try shooting a middle-of-the-histogram exposure, that way you don’t add too much noise when you bring the exposure up in post-processing. You can bring the exposure down for the shadow detail, and your in-camera exposure will handle the mid-tones. You can obviously break it out into more exposures if you like, but 3 often will do the job.

    Elsinore, what are you using to make the HDRs, and how are you splitting the images? I spent a lot of time fighting with Photoshop CS2 and raw images, trying to split one raw shot into 3. Unlike with my bracketed shots, which worked fine, no matter how I split out the images, I got “not enough dynamic range to construct a useful HDR image” from photoshop. I played with moving EV’s around, played with curves, brightness, meditated on the beauty of histogram curves, but nothing I did seemed to work. This leaves me decidedly grumpy, ’cause I can see making some fun shots of my nephews this way for my sister, and they can’t stay still for 3 whole shots!

    Maybe I just need to go download the HDR stuff for the gimp.

    #6922
    mikemikeb
    Participant

    I spent a lot of time fighting with Photoshop CS2 and raw images, trying to split one raw shot into 3. Unlike with my bracketed shots, which worked fine, no matter how I split out the images, I got “not enough dynamic range to construct a useful HDR image” from photoshop. I played with moving EV’s around, played with curves, brightness, meditated on the beauty of histogram curves, but nothing I did seemed to work.

    I don’t know myself, but if you don’t get a reply from her, I suggest private messaging SaintDiluted and/or chakalakasp with that question. Better yet, how about asking one of them pubicly how to do that, and have ’em post a response in this thread, or a new one?

    Maybe I just need to go download the HDR stuff for the gimp.

    Don’t do that! That stuff’s almost worthless if you want a good HDR result.

    #6923
    Elsinore
    Keymaster

    Well, never fear mikemikeb, I’m here :roll:. Given I have gotten good results with GIMP, I wouldn’t call it worthless, but YMMV. As I stated in the other thread, better results are possible using *both* the Dynamic Range Extender plugin and the Shadow Recovery plugin. With both of those tools, I was able to approximate the “Cabin in the Smokes” results long before I even had any true HDR tools to use under Linux. I posted my process and results in the same thread mikemikeb links to, though it’s at the beginning of the thread. It’s also important to note that given you’re only combining 2 exposures with the DRE plugin, you simply aren’t going to be performing any miracles, to expect perfection is pretty silly.

    Now, if you want to do true HDR under Linux, it’s simply not possible using GIMP alone. You need to use the UFRAW plugin for GIMP to read/edit RAW files, Cinepaint/Film GIMP, which can assemble an HDR file (.exr extension, typically), then pfstools (command line interface) or qpfstmo (gui interface using pfstools) to do the tonemapping. GIMP can do final editing after that. It’s admittedly a much more involved and less user friendly undertaking than what’s available under Windows or Mac. However, I doubt very much that anneb is using Linux, so to return to her question to me…

    What I have been doing is taking my RAW file and setting a base exposure (say default, out of camera, or possibly -.25 or -.5 EV), then saving that file as a .png which is lossless. I then open the RAW file again, and set a higher exposure and save that off as another .png. Rinse, repeat, wipe hands on pants for 3-7 exposures. I space the exposures evenly, a third, half, or full stop apart. My images might be -0.5EV, 0, +0.5EV, +1EV, +1.5EV or some such. After I get all of my exposures saved off, I then open Cinepaint and tell it to create an HDR from all of them. I don’t know CS2 (and hopefully someone else can clarify this to be the case), but I’m guessing it would be a similar situation under PhotoShop where you save off your differently exposed images first, then open them back up in CS2 and tell it to assemble the HDR file.

    Don’t believe for a minute there isn’t enough dynamic range in a single RAW file, despite Adobe’s protestations. A digital camera is capturing a lot more data than it can display in a single image, and RAW contains even more data than .jpg. So assembling an HDR from a single RAW file is just using more of the information already locked away in it.

    As for HDR under GIMP, if you’d like to give it a go with the Dynamic Range Extender, it can’t hurt (and it’s free–can’t argue with free), but I would strongly suggest you also get the Shadow Recovery plugin as well. The combination of the two (or in same cases one over the other–every image is different, after all, and may need different treatments) seems to work very well for LDR approximation of HDR. If you give GIMP and/or the plugins a try, I’d also suggest trying it out for more than a few days before throwing in the towel. GIMP is a very powerful image editor, but sometimes the methods or tools used will be a bit different than under CS2/PS. And of course, with any new tool with any complexity involved, you’re going to have a learning curve, so consider that as well.

    On thing that might be in GIMP’s favor is that you say you want to do some HDR stuff with your nephew. You might get more natural results with the DRE and/or Shadow Recovery plugins, or even the Shadow Recovery tools in CS2/stacking exposures, etc. With some HDR tone mappers, human skin can take on an unnatural appearance (like everything else 😉 ), so keep that in mind.

    Anyway, hope that helps some, even if I’m not SaintDiluted or chakalakasp 🙄

    #6924
    SaintDiluted
    Participant

    hehe… I don’t know as I’m an expert in this area.. I use Photomatix to make HDRs. The reason that photoshop gets upset is that when you change exposure and save the images again, the EXIF information no longer has an exposure value for photoshop to work with. Photomatix takes it’s best guess as to what the exposure values are when you tell it to make an HDR.

    You could probably use an EXIF editor to add the EV into the image.. you might try that.

    #6925
    Elsinore
    Keymaster

    Ahh now that makes sense. When I do my exposures with UFRAW/GIMP, it doesn’t wipe the EXIF (though I guess it doesn’t really apply, since I changed the EV), but Cinepaint lets me tell it what my exposure values are for each file.

    So maybe Photomatix would be an option for you, anneb?

    #6926
    mikemikeb
    Participant

    The reason that photoshop gets upset is that when you change exposure and save the images again, the EXIF information no longer has an exposure value for photoshop to work with. … You could probably use an EXIF editor to add the EV into the image.. you might try that.

    What about this: If saving to .png strips a RAW file of the EXIF data, how about a Save As of the unedited RAW file to PNG and working on the HDR from there? Or does the .png conversion keep the EXIF data? Is that what you already do, Elsinore?

    #6927
    anneb
    Participant

    However, I doubt very much that anneb is using Linux, so to return to her question to me…

    Ha-HA, right you are! I’m actually using a FreeBSD system! Well, ok, and a Mac, but even it is BSD under the hood… I do have GIMP on both boxen, I just find going through folders of photos just easier on the Mac. The real trigger that moved me to photoshop a while back was that at that point, GIMP wasn’t giving me the batch RAW processing (let alone single shot processing) that CS was. Then CS2 appeared, when I could get a student discount.

    I’ll tell you, it was really cool playing with the curves on the HDR merge in CS2, I felt like I had some semblance of fine tuning control, even on my first real attempt at it. And, in the interests of keeping my life simple, I’d rather get things to work in Photoshop. But I popped over to look at Photomatix, I probably will at least get it and play a little- probably quite high on my to-do list for my Copious Free Time (ARGH)

    Don’t believe for a minute there isn’t enough dynamic range in a single RAW file, despite Adobe’s protestations. A digital camera is capturing a lot more data than it can display in a single image, and RAW contains even more data than .jpg. So assembling an HDR from a single RAW file is just using more of the information already locked away in it.

    Having stared at the histograms of what worked vs. the ones it claims didn’t have useful dynamic range, I’m quite convinced of that myself. The problem is trying to fool photoshop, it seems.

    … but I would strongly suggest you also get the Shadow Recovery plugin as well. The combination of the two (or in same cases one over the other–every image is different, after all, and may need different treatments) seems to work very well for LDR approximation of HDR.

    added to [ever increasing] list…

    On thing that might be in GIMP’s favor is that you say you want to do some HDR stuff with your nephew.

    Quite possibly, eldest nephew is definitely more interested in the camera stuff than my son is. That’s indeed a thought for him.

    Thanks for all the thoughts, I’ve got more to play around with, now 🙂

    #6928
    anneb
    Participant

    hehe… I don’t know as I’m an expert in this area.. I use Photomatix to make HDRs. The reason that photoshop gets upset is that when you change exposure and save the images again, the EXIF information no longer has an exposure value for photoshop to work with. Photomatix takes it’s best guess as to what the exposure values are when you tell it to make an HDR.

    You could probably use an EXIF editor to add the EV into the image.. you might try that.

    Heh- or toss it through an older version of GIMP, that strips off EXIF, and then send it back to Photoshop. Or is that cheating?

    I hadn’t thought about PNG, I usually think “TIFF” for lossless. I’ll have to see what each does.

    #6929
    Elsinore
    Keymaster

    I typically use png over tiff because tiff isn’t truly standardized. I discoverd this when I tried out Bibble and found that GIMP didn’t like Bibble’s tiffs and Bibble didn’t like GIMP’s tiffs. They had a tiff over their tiffs…ha ha, I’ll be here all week, try the HDR veal!

    But seriously, rock on with your BSD box and your Mac! It sounds like you don’t have the UFRAW plugin for GIMP though? It can process RAW files, and as long as you have a recent exif lib, it shouldn’t strip your exif data. It uses DCRAW under the hood (DCRAW being command line), but has a very easy to use interface. One downside, though is lack of batch processing in the GUI, though you can do it through command line (if you really want to punish yourself like that 😉 ) If you want to check into UFRAW, you can get it at http://ufraw.sourceforge.net .

    If you want an EXIF manipulation program, you can look into http://www.exiv2.org , though it sounds like stripping the EXIF won’t necessarily help you if PS is looking for it. And png’s and tiff’s don’t store it anyway, so if it’s an issue of PS demanding it, you may not be able to fool it.

    If you want to go hardcore geek (cause it sounds like you’re already there, anyway 😉 ) you can look at the combination I’m using of UFRAW/GIMP for RAW processing and final editing, Cinepaint (GIMP derivitive based on 1.1) for HDR generation, and qpfstmo (GUI interface for pfstools) for tone mapping. My hubby just told me there’s a specific pfstools package for freeBSD, so as long as you have pfstools and Qt, you should be able to get it running on your system. I think the only downside to the whole system is that qpfstmo outputs 8bit png’s rather than 16 bit, though ultimately GIMP can only deal with 8 bit anyway. It sure would be nice if GIMP 2.4 had support for 16 or 32 bits/channel….

    #6930
    mikemikeb
    Participant

    I typically use png over tiff because tiff isn’t truly standardized. I discoverd this when I tried out Bibble and found that GIMP didn’t like Bibble’s tiffs and Bibble didn’t like GIMP’s tiffs.

    If we’re going from unprocessed RAW to final full-sized HDR JPEG in a single program (like CS2), then this shouldn’t be much of a problem. Besides, chakalakasp would say that it’s best to reach the 8-bit/JPEG level in CS2, anyway.

    If you want an EXIF manipulation program, you can look into http://www.exiv2.org , though it sounds like stripping the EXIF won’t necessarily help you if PS is looking for it. And png’s and tiff’s don’t store it anyway, so if it’s an issue of PS demanding it, you may not be able to fool it.

    Hopefully CS2 doesn’t care if all the images are EXIF-free. It shouldn’t. Also, according to Wikipedia, EXIF suppots TIFF files

    I think the only downside to the whole system is that qpfstmo outputs 8bit png’s rather than 16 bit, though ultimately GIMP can only deal with 8 bit anyway. It sure would be nice if GIMP 2.4 had support for 16 or 32 bits/channel….

    If I remember correctly, most DSLR’s (including modern Canons) have 12-bit RAW. Saving to 8-bit PNG will reduce overall dynamic range, right? If so, then saving to PNG doesn’t look too good for people with GIMP… Of course, if you’re using CS2, I guess that doesn’t apply, and I suppose that GIMP’s image scaling and JPEG editor/saving tools are underappreciated, and a full-size JPEG saved from CS2 will work fine in GIMP.

    #6931
    Elsinore
    Keymaster

    Well I did miss that TIFF supports EXIF, but that doesn’t change the fact that TIFF isn’t standardized (besides creating HUGE file sizes), so if you’re someone like anneb working cross-platform and/or with more than one program, that could still be an issue.

    As for going from 12bit RAW to 8bit png and dynamic range loss, isn’t that what I said and you quoted? GIMP only works in 8bit, so there’s dynamic range loss anyway. As I said above, that’s the big disadvantage to using qpfstmo/GIMP for HDR, but it still seems to work reasonably well, even if it’s only 8 bit/channel. Given that jpg is lossy while png/tiff are not, why would you want to output a jpg from CS2 to work in GIMP or qpfstmo? If you’re outputting to an 8bit file anyway, lossless would certainly be preferable to lossy….

    But GIMP’s image scaling and jpg compression are absolutely underappreciated. I learned just how good GIMP is with scaling/compression when I tried out Bibble, which output greater compression artifacts at larger file sizes for the same compression level as GIMP. That was probably one of the biggest drawbacks of Bibble for me.

    #6932
    mikemikeb
    Participant

    As for going from 12bit RAW to 8bit png and dynamic range loss, isn’t that what I said and you quoted? GIMP only works in 8bit, so there’s dynamic range loss anyway.

    I wasn’t quite sure if lowering bits always means lowering DR. I’m not as much of a techie as you are.

    In addition, I talked about how you don’t need to open up GIMP until you have the final full-sized JPEG of the intended image, as long as you have CS2, or Photomatix, or a combination of other image tools that do work in 16-bit.

    Given that jpg is lossy while png/tiff are not, why would you want to output a jpg from CS2 to work in GIMP or qpfstmo? If you’re outputting to an 8bit file anyway, lossless would certainly be preferable to lossy….

    Because chakalakasp‘s tutorial (see above link of mine) talks about how one’s supposed to downsample all the way to 8 bit in CS2 and save a JPEG from there (and to save 16-bit and up files before downsampling to 8-bit as well). I trust what he says there.

    But GIMP’s image scaling and jpg compression are absolutely underappreciated. I learned just how good GIMP is with scaling/compression when I tried out Bibble, which output greater compression artifacts at larger file sizes for the same compression level as GIMP. That was probably one of the biggest drawbacks of Bibble for me.

    And then there’s Photoshop. With the JPEG compression tool alone, there’s not as much compression fine-tuning (in Photoshop, it’s “10” vs. “11” quality, versus something like 85 and 86% quality in GIMP), or real-time image size preview, or as many ways to customize the final image (is EXIF data desired, is 1×1, 1×1, 1×1 or 2×2, 1×1, 1×1 color subsampling desired, etc.). I don’t even know for sure how good it does at compression of smaller images (proportionally vs. GIMP) because the JPEG editor is so feature-poor I don’t bother using it anymore (except for when I was just re-checking it out to get my stats checked). I won’t even get to the image scaling tool.

    (Edited to add full disclosure: I have Elements 3 installed on my computer. If you have CS2, and it seems like I’m making baseless facts, I’m sorry. If I’m mostly, or even 100% right about your version, even though I’ve never operated it, then Adobe, um, let’s just say they have some work to do and leave it at that, OK?)

    #6933
    Elsinore
    Keymaster

    Because chakalakasp‘s tutorial (see above link) talks about how one’s supposed to downsample all the way to 8 bit in CS2 and save a JPEG from there (and to save 16-bit and up files before downsampling to 8-bit, as well). I trust what he says there.

    That’s great if you’re using a single program and it makes total sense in that context. It won’t work as well for the method I’m discussing with anneb, the method I use which requires more than one program.

    And then there’s Photoshop. With that tool, there’s no real-time compression preview, nor does it have as much compression fine-tuning, or as many ways to customize the final image (is EXIF data desired, is 1×1, 1×1, 1×1 or 2×2, 1×1,1×1 color subsampling desired, etc.). I don’t even know for sure how good it does at compression of smaller images because the JPEG editor is so feature-poor I don’t bother using it anymore.

    So are you using GIMP for general image editing?

    #6934
    mikemikeb
    Participant

    Because chakalakasp‘s tutorial (see above link) talks about how one’s supposed to downsample all the way to 8 bit in CS2 and save a JPEG from there (and to save 16-bit and up files before downsampling to 8-bit, as well). I trust what he says there.

    That’s great if you’re using a single program and it makes total sense in that context. It won’t work as well for the method I’m discussing with anneb, the method I use which requires more than one program.

    anneb wants to use CS2 alone:

    I’ll tell you, it was really cool playing with the curves on the HDR merge in CS2, I felt like I had some semblance of fine tuning control, even on my first real attempt at it. And, in the interests of keeping my life simple, I’d rather get things to work in Photoshop.

    I know that you have to do things differently as you use Linux. Sorry for any confusion.

    So are you using GIMP for general image editing?

    Yeah. I currently only work with JPEG, though I do have RAW versions of some photos (like the HDR theme sources).

    #6935
    Elsinore
    Keymaster

    Except she also mentioned she’s going to give Photomatix a try, as well as GIMP which she already has experience with.

    It also doesn’t change the fact that I was discussing a specific process (a discussion aimed at her since she did originally ask me rather specifically), and it also doesn’t change the fact that she’s working on multiple platforms, so the points I brought up are specifically germane to her system(s) and options she may want to consider.

    But by all means, please feel free to keep nitpicking the things I say rather than concede that I have anything of value to add to a conversation that was aimed at me in the first place 🙄

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