Photo merge / Panorama tips

Discussion in 'Digital Photography' started by NStocks, May 6, 2010.

  1. NStocks macrumors 65816

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    #1
    Hello,

    So I want to capture a panorama of a street for a project I'm working on. The buildings ( 10 ) are around 15 metres tall and on a hill. The street isn't particularly wide so there will be some upward distortion due to me having to hold up the camera in order to capture the whole building.

    What would be the best way of undertaking such a photo and are there any important tips that will help me when processing, other than to keep all the setting the same ( Samsung GX10 with a 18-55mm lens, should I use f/11 for optimum depth ? )

    I think that photoshop elements can take care of the photo merge and I'm fairly sure it can help re-store the correct view of the building, rather than it been a perspective ( upward ) view.

    Thank You very much
     
  2. M-5 macrumors 65816

    M-5

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    Jan 4, 2008
    #2

    If you're going to shoot at f/11, make sure that there's enough sunlight, or your shutter speed might be too slow. I usually also resize all of the photos before importing to Photoshop, or else it'll take extremely long to merge them together. Shooting at 18mm might be good to capture more per shot and take fewer shots, but I'm thinking there might be more distortion with it. I'm not really sure, but you should post back with results and your own experience after you shoot.
     
  3. NStocks thread starter macrumors 65816

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    #3
    Kinda a ' dumb ' question but when taking the Photos, do I have to stay in the same place and just move the camera or can I stand in-front of each building, overlapping the photo to provide a reference line. Also, when I come to merging the images, should I edit them as a whole image or edit them individually, prior to being merged ? ( I'm leaning towards the option to edit after merged for a more consistent tone etc.

    For sure I will take a few test shots first, but hopefully on aperture priority I should be ok.... and no need for a tripod, but we'll see.

    Thank You
     
  4. M-5 macrumors 65816

    M-5

    Joined:
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    #4
    Yes, you should definitely stay in the same place or else the photos won't stitch together properly. The center on which the camera is rotated on is the nodal point. If you move the position of the nodal point, then the photos won't align correctly. In some instances the photos might still not align correctly, because you're rotating your body, and the nodal point is located somewhere in the center of the lens.


    And in my opinion it's best to edit them afterwords once they are all merged, or else it could be time consuming and difficult to get the same tones. However if you're shooting in RAW, then the images won't be in that format once you merge them, so you'll have to to your adjustments beforehand. Try to keep the same aperture and shutter speed for all the shots to keep the exposure the same, but if it isn't, photoshop still does a pretty good job of stitching different exposures together.
     
  5. NStocks thread starter macrumors 65816

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    #5
    Hmmm, maybe this idea won;twork afterall. If I stay in one place, the buildings in the distance will look way too small and disorted. Is there not any other way to align the images, if each image has a ' piece ' of the next image that it can relate to ?

    A panorama works because you are moving in a circular motion, a street however you are not... I don't think it will work :(


    Thanks for your help
     
  6. Ruahrc macrumors 65816

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    #6
    You can do it, just expect to do a lot of manual stitching/retouching, I am willing to bet that the automatic merging function of CS3 won't do it.

    The issue with moving between shots is parallax error. You can help mitigate this by taking many shots (only move a little bit each time) and then carefully blending the pictures together afterwards. It will be very important to stay the same distance from the buildings in every shot, so like for example make sure you're standing on the edge of the curb every time.

    I would try to move back and zoom in so that you will not have to point the camera upwards. Get the vertical lines of the buildings parallel to the edges of the frame. IMO I'd even sacrifice some of the bottom of the frame if I had to. Keystone distortion is just going to make everything that much harder to get together.

    If you shoot RAW, edit the pictures so that they have the same WB between all of them before you merge. If you shoot jpeg, change the WB to some fixed setting on the camera, not autoWB. I usually correct the following pre-mege: WB, a tiny bit of sharpness, chromatic aberrations. I do all the "artistic" adjustments after the stitch. It goes without saying that you should use manual exposure so that the exposure will not change from picture to picture. Expose it such that the brightest frame will not have any blowouts. Also use manual focus so that the focus does not change between shots either. Again it will be critical to maintain a fixed distance in front of each building especially if you're using manual focus and can't change it between shots.

    This type of "translated" pano is pretty tricky although it can be done if executed carefully. Here's one I made, taking a picture standing in front of each dragon as I walked across it. I had to manually blend much of this together, and them imported it into Hugin for geometry correction. It hangs from my wall, printed at a little less than 4 feet wide :)

    http://www-personal.umich.edu/~nakm/20080700china/content/China_2008_900_large.html

    Ruahrc
     
  7. NStocks thread starter macrumors 65816

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    #7
    Thank you Ruahrc...

    When you mean manual stitching, how do I manually stitch it and how long would it take i.e a day, a week ( I know this depends on how many shots. )

    Should I move about a foot in distance each time to get the best possible stitch as I can, and what is people are in one image and not another i.e shop window, would I just manually edit them out ? As the buildings are on a hill, should I mainly focus on the building, then just worry about the pavement afterwards as it isn't as important ?

    I have CS5 ( trial ) and this may have some new features that will help me too.

    EDIT: This is extremely inspiring in terms of ease ! http://www.youtube.com/watch?v=C2mnHIr3Lcs&feature=related
     
  8. NStocks thread starter macrumors 65816

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    #8
    I've taken 16 photo's, all with equal settings an distance from the building...

    Heres a screnshot of what Photoshop CS5 ( 2010 ) has managed, no edits from any other software, just straight out the camera...


    As you can see, it is a mess. 2 or 3 of the buildings line up, but are then separated from the other ones, and I have not idea what's going on with the image on the bottom... that was the first photo !

    I'm going to look into manually aligning them, but not sure how it's done and also look at how to fix the upward distortion (?)

    Thank You
     

    Attached Files:

  9. NStocks thread starter macrumors 65816

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    #9
    And here's the other view... Needs a lot of work doing to it !
     

    Attached Files:

  10. Ruahrc macrumors 65816

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    #10
    What I meant by manually merging was like to put each new picture in a layer and move it around until it lines up, and then use manual blending tools with the masking tool to get a good blend.

    This really isn't going to work with the vertical perspective distortion like that. The buildings need to be straight-on and the verticals need to be absolutely vertical. You can probably try to fix each image using the perspective tool first (better to use the lens correction tool to fix barrel distortion as well), then re-trying the merge function or do it manually.

    http://hugin.sourceforge.net/tutorials/perspective/en.shtml

    There's a good starting place on perspective distortion, you may not use Hugin but these concepts on perspective are universal. Also look up "linear panorama" to see some examples of what you're going after

    Don't feel too bad as linear panoramas are very challenging. To be honest it is probably not a good idea to try linear panos as your first stitching experiment, as it is quite tricky and really needs a good understanding of the stitching process and multi-shot panorama issues before really knowing how to both shoot the correct source material (to avoid the perspective challenges) and also how to properly assemble them.

    Ruahrc
     
  11. NStocks thread starter macrumors 65816

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    #11
    Yeah, it's not looking good really... the building are fairly tall and the only way to capture them was to point the camera up... I'll take a look at the info gave me, maybe I will have something that looks half decent at least. ( or am I wasting my time due to the distortion ?)

    Thank You

    Nathan
     
  12. NStocks thread starter macrumors 65816

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    #12
    Attempt 2. This time I have corrected the vertical and barrel distortion ( well at least I though I had ), the image isn't much better... I'm still reading the Hugin tutorial but would that program work better for me ?

    Thank You
     

    Attached Files:

  13. NStocks thread starter macrumors 65816

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    #13
    OK, heres another attempt. This time I've done it manually in CS5 and used the " Auto Blend Layers " option which really helped out at the end...

    I spend 15 minutes on this and not all the photos are there, I just wanted to see what was possible... I think that if I spend a bit more time, and process the image before merging ( white balance etc ) then I should have something that is satisfactory... I know I'm not going to get it perfect but that can't be helped due to the size of the building, the distance from me to the building and I the lowest focal length lens I have is 18mm... I've done as much as I can given the above parameters....

    I'm also trying other programs, but I feel that manual will work better.

    Thank You
     

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