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Monday, October 24, 2011

Techniques... photo-stitching

I have had a few questions from people asking me about the "long pictures"(photo-stitched together), panoramas, hanging in the studio and in the ad-agencies i work for/with.
So i decided to write a small article on the subject.
Please note that this is the way i do it and that it is in no way the start and end of how to do it, this simply is how i simplified the technique and it works for me.

                 This was around 15 images stitched together, file-size is about 65MB j-peg file.

When you see a scene like this and you want to capture the scene from side to side, make sure of a few things and follow my rules and you should be ok.

No filters on the lens. As you are going to swing from side to side the way the light falls onto the scene and the way the light falls on the filter will change.

There are no limit to how many images you can put together,- just remember, the more images, the bigger the file-size, the longer a computer take to proses the files.

The closer you are to a scene the closer together your images must be stacked, otherwise the perspective will change to much, e.g a building is close to the end of the image it will look like it is leaning to one side.
That said,- sometimes it can/will work for you, after all art is subjective. The clients loved this one and didn't want me to rectify the perspective.

    Notice how the wall in the fore-ground curves and the buildings on the side is not 'square' to the scene
               This image was around 12 from side to side, and 2 from top to bottom. 75MB j-peg

This technique  can be used horizontally or vertically, as below.

                           This beautiful buildings in Hong Kong was 5 x images stitched vertically
                                                                          50MB j-pegs

1. Set the ISO to where you general shoot for the scene in front of you. I shoot ISO 100 in daylight. Your choice.

2. Set the Light-meter according to your scene, e.g sunny/cloudy/shady etc. Try to stay away from AWB as this may affect your picture.

3. Set your camera on AV function. As a general rule in photography F8 is one of the most reliable F-stops to have everything in focus.

4. In AV mode look through the viewfinder and while half-pressing the shutter move from the one side to the other over the scene you want to capture. While you are doing this look in the viewfinder at what the shutter-speed is doing,- it will give you more than one speed-count as the light change through the lens. Take note of the highest and the lowest of the shutter-speeds.

5. Now, set the camera on M (manual mode). You have already set the ISO and WB, so all you have to set is the F-stop, F8 remember and then set the Shutter-speed to the fastest speed the camera showed you when you did number 4 above, remember?
I always chose the fastest speed because you can always bring dark areas back if a bid under-exposed, but when it is to bright (over-exposed) the details are burn-out and nothing can recover it.

6. I'm not going to teach you how to stand and hold the camera, but you should stand firm and be able to swing the top part of your body from one side of the scene to the other with-out moving your feet.
Make sure your focus is on the part most important part of your scene,- you have to decide this for yourself.
I normally swing once or twice through the scene without shooting,- half-pressing the shutter button to make sure i am not over-exposing and also to get a horizontal or vertical 'line' in the scene on witch to keep the scene strait.
Before i do no 7 i try to shoot a shot of my hand or foot and again one of my hand or foot after the panorama shots. I do this to simplify the post production, to know were a panorama start/ends. Believe me,- you shoot a few, one after the other, you would want to know where the one starts and ends.

7. Shoot! Take your time and shoot along the 'line' in 6 above. You should overlay your images not less than 25% over the next one.

                            This was made in the Kruger National Park. 21 images, 75 MB j-peg

8. Post production. I do the automate in Photo Shop CS 4,- it is yet to let me down. If you prefer you can place the images manually and move them by hand until correct in PS. This is quicker;
 In Photo Shop >file >automate >photo-merge >chose images. Remember to flatten image when you are done and continue with post production until happy :)

9. When you have a final image on witch the perspective is off,-like building leaning to their sides, correct it in PS like this;
In PS > edit > transform > Perspective > get the rectangular marquee tool > mark the image from border to border > 'pull' the image on the top/bottom corners until correct. Ps,- this will 'shorten' the image if done to extensively.

10. This is only the basics to help you get started. At my workshops we go into this in more detail and cover the post processing in detail.

Once you master this technique it can be done even with moving subjects/objects in the scene. Have a look at the blog-post named Youth Community Project 6 and you will see a image with soccer players i made while they were playing!

I love to make these kind of images as the are something special and always gets comments and framed they look absolutely look breathtaking.
Remember; "NO! Try not. Do or do not. There is no try." - YODA

                                   This image was made-up of about 25 shots. 150MB j-peg.
           Made next to the N1 close to Vereeniging at an roadside stop with a scrapyard and truck-stop

If you liked this, please join me at my next workshop and learn more about photography and how to get better, learn more and ultimately enjoy this art-form more.

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