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There are times while photographing that you may want to have more of your image in focus than is possible in a single shot unless you have a perspective control tilt shift lens. Even if you theoretically could stop down and have most of the image in focus perhaps that would require a slower shutter speed than is possible due to wind or subject movement. Or perhaps you want to shoot wide open to maintain an out-of-focus background but be able to capture all parts of your subject in sharp focus. Taking multiple shots wide open while bearing the focus makes that possible. You can take numerous shots with different parts of the scene in focus and have Photoshop automatically combine them. Don't change the exposure, just the focus. You don't want to change the aperture, the shutter speed, the ISO, or the placement of the camera, just the focus. Of course, with just two shots you could manually drag one on top of the other, add a Layer Mask to the top Layer and use the sharp parts of each image, but often you'll need more than two shots and finding the sharp parts might be quite time consuming. In Photoshop CS4 you could take advantage of Scripts to automate this process and to enable you to use as many shots as you need. To begin, open the images into Photoshop. I've opened nine images. As you can see this first one just has the very tips of the flowers in focus and everything else is blurred. I varied the focus progressively on each of the images. I'll begin by going to File, Scripts, Load Files into Stacks, and then choose Add Open Files. I'll also check Attempt to automatically align source images and click OK. Photoshop is taking all nine images and putting them into a single image with nine different Layers and then it's working on aligning each of those nine images. Next, hold down the Shift key and click the top layer so that all my layers are selected and I'll come up here to Edit, Auto Blend Layers. If I hadn't had the Script also do the alignment I could use Auto Align Layers. So, I'll click on Auto Blend Layers and notice that you can use this method for a panorama as well, but in this case we're interested in stacked images and we'll check Seamless Tones and Colors and click OK. Photoshop is going to begin working on choosing the sharp part of each image to create one final image that is sharp throughout. Of course, since the background is blurred in all of the images the background of the image is going to remain blurred. Considering the amount of work that Photoshop is doing it's actually processing pretty quickly but it does take a minute or two. The more images the longer it takes. As you can tell from the Masks, Photoshop has carefully selected the sharp parts of each Mask in ways that would have been very, very difficult for you to do manually. The more perfect the initial alignment of images the better the results. At this point I'll need to Crop the image slightly to get rid of the extra transparent pixels and now I have my final result. A sharp image throughout the flower with a blurred background. Some people like the program Helicon Focus for extended depth of field images, but before you put out the money for that program I'd give Photoshop a try. It works pretty well for extending depth of field in images.
| Course: | Adobe Photoshop CS4 for Photographers |
| Author: | Ellen Anon |
| SKU: | 34036 |
| ISBN: | 1-935320-74-2 |
| Release Date: | 2009-09-23 |
| Duration: | 8.5 hrs / 112 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |