Tuesday, March 29, 2011

P&S: behind the scene Pano, Horseshoe Bay, BC

I know a lot of you use point & Shoot cameras to document your journey(s). I use a P&S as my regular pocket camera but when I want to do more serious stuff I use my dSLR. I have a Canon G10 which doesn't really get much use as it does not have HD video but it shoots RAW and is nearly, fully adjustable. My Lumix ZS3 gets the most use and it produces very nice 720p AVCHD video. This camera is now 2 generations old and only has Auto modes which can be a problem when stitching images together. The light levels will not be constant throughout the scene meaning that your camera will probably chose different shutter/aperature settings for every photo which will be a problem with colour balance as a panoramic image may be anywhere from 100° - 180° view. I have a work around which you may wish to try for yourself. My normal panos are usually produced from 3 images. Now this will work for landscapes where your focus point is nearly at infinity (or any point farther than, perhaps 30 ft).

I first survey the scene before me to determine the light values and decide which slice of the scene before me I wish to capture. I do all of my Panos, hand-held, which isn't the best. Really you should use a levelled tripod otherwise you cannot be sure you take every shot on the same horizontal plane. Once I determine what I wish to photograph I point my camera at what will be the middle image in my perceived scene and I notice what settings the camera has chosen. I also make a mental note of where my centre focus point is. I gently "click" the shutter and wait a moment for the camera to go back to ready mode. While all this is happening I make sure that I do not move my camera from its position as I have to rotate the camera on its nodal point, which is the mid-point distance from the sensor to the end of the lens. Do not assume that the tripod socket is the nodal point, as it is not.

With the camera in exactly the same position as was used to take the first photo I gently press the shutter button half way to lock focus and exposure. I make sure that the centre focus point is on top of what it was on the first photo and look at the settings the camera has chosen, and it should be the same as was used on the first photo. With the shutter button still half depressed, I now rotate the camera to take photo two. It doesn't matter whether you take the left one or the right one but rotate the camera on it's nodal point making sure to keep the same horizontal plane and allow at least 25% overlap. Remember not to move the camera from its original position.

When the camera is ready, focus again as you took the first photo and rotate to take the third one. It is easier to do this than it is to explain it. You can probably take all three photos in this sequence in about 5 seconds. Of course you are not limited to only 3 photos, you can use many more For stitching panoramic images I use a FREE program called Autostitch.

Here is a link to where you can download it

http://cvlab.epfl.ch/~brown/autostitch/autostitch.html

After you start the program go first to Edit, Options and you will get a screen like this


autostitch


Don't change too many numbers but pay attention to those two boxes numbered 1 and 2. This is where you can control how large your resultant jpeg is. You can take a small megapixel camera and cumulate the pixels added by each image and end up with a very large file. For best printing results stick with 300 dpi

Note: make sure all your images are in the same directory, preferably consecutively numbered and hold Shift/click to select all the ones in the sequence. The program then starts processing without warning, all done automatically before your eyes

Here is the image which was produced by my Lumix ZS3 using my work-around technique comprised of 7 separate 10 MP images

horseshoebay2 crop 27mar
(Lumix ZS3 stitched from 7 images using Autostitch)


for the full sized version from Photobucket, click here <------- * * Make sure to click "+" to go to full size

Now go and try it for yourself

9 comments:

  1. Nice tutorial on making panoramas. On OS X, I really like the way DoubleTake works. But I have been using AutoStitch on the iPhone at least as often. When using photos from my dSLR, I occasionally get some "banding" even if I lock the exposure. I haven't figured out why. With the iPhone, it is a challenge getting the exposures consistent between images. Fortunately, with the Camera+ app, you can independently control exposure and focus which helps.

    Richard

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  2. Beautiful panorama of the bay! I think I can see the curvature of the earth.

    Great tutorial. The only time I was ever serious about creating a panorama was for a mountain/valley scene. Mountain on the left and valley on the right. There was no way I was keeping it level. :)

    I haven't tried AutoStitch. I used the PhotoStitch that came with the Canon software and liked it very much.

    -Lori/Steel Cupcake

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  3. great pano and tutorial Bob!

    I used the exposure lock on my old Olympia C4000 ( I miss that camera sometimes), on the Lumix I use the panorama assist feature which seems to lock exposures.

    And you are so right that using a tripod is better in terms of leveling out the picture.

    dom


    Redleg's Rides

    Colorado Motorcycle Travel Examiner

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  4. Dear Bobby:

    This post is too complicated for me. So I left a note on the previous post.

    Sincerely,
    Jack • reep • Toad
    Twisted Roads
    The Bermuda Triangle of Biker Bogs

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  5. Bobby

    I normally forget from where I started and so my nodal point falls off the richter scale.

    Yours as ever from West Benghazi, N

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  6. Bob:
    Thanks very much for that tutorial, particularly Autostitch. I have the Canon stitch program which is very limited.

    I think you've just improved my photo-taking ability at a stroke so thanks again!

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  7. "more serious picture taking"? Does everyone stand around frowning with their SLRs in British Columbia as they calculate the cost of a liter of gas as opposed to the cost of a surgical co-pay in a US hospital? And how do you photograph that, seriously? With levity...?

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  8. Richard:

    Do you have a filter on your dSLR ? Autostitch has auto leveling

    Beemergirl:

    curvature is my fault. I should not have used wide angle. the sweet spot is 45mm equivalent

    Charlie6:

    I see panoassist on the menu but I don't know how to use it. It works differently than on my Canon

    Jack:

    I did this for you, it's so simple. Harder to explain than to do

    Nikos:

    I hope your Nodal Point didn't break, they are hard to replace

    Geoff:

    I often take a series of photos. I have some from the Grand Canyon from years ago I took because I thought that one day, I will know how to assemble them

    Mr Conchscooter:

    Precisely why I wanted to show you how to stitch a few images together with FREE software. you can do it even with your pocket camera

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  9. Which program do you use to process the G10's raw files? I have Photoshop Elements 9 which is supposed to have the ACR for the G11 but it doesn't seem to work.

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