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Thread: Sky replacement in handheld images merged in Photoshop

  1. #1
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    Sky replacement in handheld images merged in Photoshop

    I have to confess to a bad habit: shooting handheld HDRs.

    About 2/3 of the time I get away with it, and I can align my images, but experience has taught me that merging them in Photoshop is far more reliable than merging them in anything else.

    Once I have an .exr from this I tend to tonemap it in both Photomatix and HDR Expose, and then layer them together in Photoshop and pick and choose what I like from each layer to produce the image that I further post process.

    My problem with this process is that I often wish I could merge the sky back from one of my original captures to replace the mess (IMHO) that HDR tonemapping makes of clouds/skies.

    The advantage of having the single merge from Photoshop, that the two different tonemapped versions will align perfectly, now proves a problem, because none of the original images exactly matches the .exr, because of my bad habit of shooting handheld, ie Photoshop has moved stuff around to align my images.

    Many panoramic programs let you choose the image that is the 'reference' image for alignment, but Photoshop does not.

    Does anybody know a way round this?

    Cheers

    Nik

  2. #2

    Re: Sky replacement in handheld images merged in Photoshop

    Quote Originally Posted by lnikj View Post
    I have to confess to a bad habit: shooting handheld HDRs.
    Want to hear about mine?

    Seriously, why don't you use a tripod? What version of Photoshop are you using?

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    Re: Sky replacement in handheld images merged in Photoshop

    Hi Rob.

    Ermmm .... generally one of 3 things .... laziness, the look that comes over my GFs face when I say "I'll just set the tripod up dearest, I'll only be a moment", or more seriously that many HDRs I take are urban in situations where I like to use them to help with the difference between dark streets and bright overhead skies, and I don't want to get mugged, run over etc.

    Point taken, however :-)

    CS5 on Leopard.

    Cheers

    Nik

  4. #4

    Re: Sky replacement in handheld images merged in Photoshop

    Quote Originally Posted by lnikj View Post
    Hi Rob.

    Ermmm .... generally one of 3 things .... laziness, the look that comes over my GFs face when I say "I'll just set the tripod up dearest, I'll only be a moment", or more seriously that many HDRs I take are urban in situations where I like to use them to help with the difference between dark streets and bright overhead skies, and I don't want to get mugged, run over etc.

    Point taken, however :-)

    CS5 on Leopard.

    Cheers

    Nik
    Nik

    You can overcome the last two reasons by getting your GF to take up both photography and karate!

    I have only just installed CS5. I'll try a hand-held HDR later to see how it does it in CS5.

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    Moderator Donald's Avatar
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    Re: Sky replacement in handheld images merged in Photoshop

    You can overcome the last two reasons by getting your GF to take up both photography and karate
    Or, invest in a good set of GND Filters and then you won't have to worry as much about all that blending-images-in-a-computer-programme stuff. And your GF can be involved holding the boxes and passing you the filters as you change them (as long as she holds them at the edges and doesn't get smudges on them!)

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    Moderator Dave Humphries's Avatar
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    Re: Sky replacement in handheld images merged in Photoshop

    Quote Originally Posted by Donald View Post
    ~ And your GF can be involved holding the boxes and passing you the filters as you change them (as long as she holds them at the edges and doesn't get smudges on them!)
    Or use them as a make up mirror and drop powder all over them

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    Re: Sky replacement in handheld images merged in Photoshop

    Quote Originally Posted by lnikj View Post
    I have to confess to a bad habit: shooting handheld HDRs.

    About 2/3 of the time I get away with it, and I can align my images, but experience has taught me that merging them in Photoshop is far more reliable than merging them in anything else.

    Once I have an .exr from this I tend to tonemap it in both Photomatix and HDR Expose, and then layer them together in Photoshop and pick and choose what I like from each layer to produce the image that I further post process.

    My problem with this process is that I often wish I could merge the sky back from one of my original captures to replace the mess (IMHO) that HDR tonemapping makes of clouds/skies.

    Does anybody know a way round this?

    Cheers

    Nik
    You might find this useful -http://digital-photography-school.co...y-in-photoshop

    HTH

    Peter

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    Re: Sky replacement in handheld images merged in Photoshop

    Thanks for all the GF advice guys :-) She is actually very tolerant of my photographic activities though I haven't persuaded her into coming on dawn shoots yet!

    Peter - thanks very much for the link, but I find it creates artifacts in the skies when used on tonemapped HDRs, even if the technique works well with normal images.

    In the time honoured tradition of answering your own question I have now found a convoluted solution! Take the merged image from photoshop and the image containing the sky that I want to use from the original sequence, and run them through the command line tool align_image_stack from the Hugin project to create two separate aligned files (not merged). Those files can then be opened in photoshop, layered together, and robert is your mother's brother.

    Or I could just use the tripod more ... :-)

    On one other note for those with my bad habit, I downloaded a demo of Photoacute and it lines up handheld sequences more reliably than any other software I've tried.

    Cheers

    Nik

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    Re: Sky replacement in handheld images merged in Photoshop

    Quote Originally Posted by lnikj View Post
    On one other note for those with my bad habit, I downloaded a demo of Photoacute and it lines up handheld sequences more reliably than any other software I've tried.
    Thanks for thinking of me

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