Have you ever had one of the following situations happen in your photography endeavors?

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1 Image Stacking by Joe Wenninger I decided to write this article myself after having issues trying to do a Median blending technique from a book about Photoshop. You needed to have the extended version of Photoshop in order to do the last step of the process. I just got my purchased Photoshop CS6 3 days ago. I was a little disappointed this feature was not in there. Since this is a Photoshop exercise, I decided to expand the article to include other stacking techniques, so anyone with Photoshop could try one of these. I also wanted to point people to workarounds in case they really want to use the technique and don t want to shell out for the extended version. Have you ever had one of the following situations happen in your photography endeavors? 1. Been in a museum without a tripod (many museums don t allow them) in a low light setting and wanted to take a high quality low noise photo of a great subject. 2. Wanted to take a picture in a crowded area of a popular attraction and did not want all the people (or traffic) there. 3. Wanted to increase your depth of Field in photograph beyond your cameras ability, so you could get the whole subject in focus. All of the problems can be solved with one of two image stacking techniques. Median blending will solve 1 and 2 above. The third problem can be solved with auto blend layers. Image Stacking is when you take multiple picture of the same subject and put them together with software. HDR is a type of staking. In many of the stacking techniques, there is something varied in the taking of each image. HDR varies the exposure and tries to keep everything else the same. Reducing noise tries to keep everything the same, except the noise which varies because of its randomness. For depth of field increase, just the focus point in each image is changed. Image stacking works best when using a tripod to control camera movement. However software is getting very good at aligning images. Photoshop does a good job of aligning images in most situations and can product excellent results. Night Photography, Astronomy and Microscopic Photography can all use stacking to improve results dramatically. Technique #1 Reducing noise though use of stacking and Median Blending (useful for low light setting).

2 1. Turn you cameras ISO high enough to get a good shutter speed, so you will have a sharp picture (limited camera shake blurring image) at the expense of higher noise (will reduce later). ISO 6400 worked good for my situation. 2. Take 10 rapid pictures of your subject (I hold down my shutter button) and hold the camera at still as you can. I use one of the dots in the view finder to make sure don t wander. You will move some but that will be corrected with auto-align software in Photoshop. 3. Upload you picture to computer. 4. Open Photoshop 5. Files Scripts Load Files into Stack 6. When load layers dialog box comes up do the following: Select all the images by using the Browse button. Then Check the Attempt to automatically align images. Then press the OK button. 7. Select All Layers (they all should all look selected). 8. Layer Smart Object Convert to Smart Object (You should only have one layer showing now) 9. Layer Smart Object Stack Mode Median (My stack mode is grayed out because I don t have CS6 extended version, only CS6). I think back to CS3 will work as long as you have the extended version. (see Photoshop work around) 10. You should have your final image with significantly reduced noise. If it is not good enough, try reducing it more with the Photoshop noise reduction () or other plug-in software (Nik for example). Work around for Technique #1 (don t have extended version) Do the same steps 1-7 above. Don t convert to smart object. 2. Blend all layers together to create an average of all images. The blending mode should already be Normal (which is good). You need to change the Opacity of all the Layers to 1/n. For example if you have 10 Layers, starting from Bottom working your way to the top the opacity would be 100%, 50%, 33%, 25%, 20%, 17%, 14%, 13%, 11%, 10% (1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10). This will create and average of all layers, which will reduce the noise, a lot (but not as good as median). Median is the equivalent of throwing the highest and lowest until there is only one value left.

3 3. You should have your final image with significantly reduced noise. If it is not good enough, try reducing it more with the Photoshop noise reduction () or other plugin software (NIK for example). Technique #2 Eliminating people (or cars) in crowded area using Median Blending. 1. Take 10 (more or less depending on situation) pictures of your subject with time gap between each one. The timing depends on what is blocking your view. Avoid shooting when something is blocking a large portion of the view. Wait till is there is significant movement of people, so they are not in the same spot. If someone sits there in the majority of your pictures they will still be there in the final image (you might have to wait several minutes between photos). I use one of the dots in the view finder to place on a specific spot on subject to keep images somewhat aligned. You will move some but that will be corrected with auto-align software in Photoshop. 2. Upload you picture to computer. 3. Open Photoshop 4. Files Scripts Load Files into Stack 5. When load layers dialog box comes up do the following: Select all the images by using the Browse button. Then Check the Attempt to automatically align images. Then press the OK button. 6. Select All Layers (they all should all look selected). 7. Layer Smart Object Convert to Smart Object (You should only have one layer showing now) 8. Layer Smart Object Stack Mode Median (My stack mode is grayed out because I don t have CS6 extended version, only CS6). I think back to CS3 will work as long as you have the extended version. (see work around) 9. You should have your final image with all the people gone. If there was someone sitting there the whole time, you can cone them out. Try selecting around the person and do a smart fill (Edit Fill Content Aware), this should finish the job. If not a small amount of cloning should. Work around for Technique #2 (don t have extended version) 1. Do the same steps 1-7 above. Don t convert to smart object. 2. Use the Layer blending and masks to create the effect manually.

4 3. Leave all layers Normal Blending and 100% opacity. 4. For all but the bottom layer, make a layer mask as follows: Layer Layer Mask Hide All. 5. When done on the bottom layer should be Visible. 6. Select the second to most bottom layers mask and paint in white around all obstructions you want removed. You can feather the edges of the paint brush. The white will cause the 2 nd bottom image to overwrite the bottom one. This will cause most the people to disappear. 7. Repeat step 6 for the 3 rd to bottom and 4 th etc., until all obstructions have been removed. Technique #3 -- Increase your depth of Field with image stacking via Auto Blend Layers command. 1. Take several pictures of your subject with different focus points. For example your first focus point would be the front rim of your flower and your last would be the back rim of your flower. You should have a few in-between as well. 2. Upload you pictures to computer. 3. Open Photoshop 4. Files Scripts Load Files into Stack 5. When load layers dialog box comes up do the following: Select all the images by using the Browse button. Then Check the Attempt to automatically align images. Then press the OK button. 6. Select All Layers (they all should all look selected). 7. Perform the Auto Blend Layers command as follows: Edit Auto-Blend-Layers Stacked Images (Check Seamless Tones and Colors) 8. Photoshop should have auto generated masks on each layer that show the best focused part of each image. The displayed image on the main window should have the best focused parts of all the layers displayed. If all looks good with the masks you could merge all visible layers and save the file. If needed you could touch up some of the masks first. 9. Enjoy your final result. Example of Technique #1 (single image as before, and final result as after). I cropped a small part of the image at 100% some you can see the detail of the noise. On the next page.

5 Before: ISO 6400, 1/30, f5.6 After: 10 (ISO 6400, 1/30, f5.6) blended together.

6 Example of Technique #3 (single image as before, and final result as after). I cropped and reduces size to show area most effected, so you can see the detail of D.O.F. Before: Single image with focal point toward the front of image.

7 After: 4 Images with blended focal points, notice detail deep in the center of the image. For those who don t have the extended version of Photoshop and really want to try the Median Blending mode you can use the following Free tools to the job done: Gimp along with the Astronomy plugin. This is not recommended unless you are good with computers. Not that easy to get up and running on your computer. If you want to give it a try the basics are below (full help is beyond the scope of this article). 1. Download and install GIMP 2.8 from 2. Download and install the Astronomy Plugin 3. Align all your images first in another tool (Photoshop for example). 4. Run Gimp

8 5. File Open as Layers select all you aligned images. 6. Filters Astronomy Merge Layers Median 7. All done If you don t have a version of Photoshop that will align your images (Elements) the Hugin tool does a great job, but it is very difficult to use because it is a very complicated panorama tool and not very user friendly. But if you are good with using this type of software it is a very powerful tool. See Link below. Make sure to look at the documentation and look at the tutorials before diving right in. The monthly Photoshop assignment as follows: Use one of the techniques in this article to make your special photograph and post on the club web site. Please add before (one of the stacked images) and after images. You decide which single technique to use. If you want use more than one go ahead. If you want to try all 3 go for it. Have fun. Download Article from PAC Club website: More Files ImageStacking Direct Link: