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With this tutorial you will learn to remove those images from your areas of focus, ie areas where your image is blurred or commonly known in photography as those areas because of the depth of field (DOF) are out of focus.
This technique is also known as bracketing Focus, Focus Stacking or Focus Blending.
Although this site is aimed at 3d programs (CGI), this tutorial can be applied very well if you want to do with your SLR camera and take pictures extending the depth of field, especially in those photos where you have to get so close to the object to be photographed.
If you want to apply to 3d renders starts from step 1-A, but if you do it with your SLR camera starts from step 1-B; Step 2 onwards is the same for both cases.
1-A.- Focus Bracketing from your 3d program
There renderers by default rendered without depth of field (everything in focus) and this is an advantage, but others as well simulate real life in the handling of light and cameras make believe when rendering depth of field . In some cases not interested in this depth of field and so the first thing to do is a sequence renders shifting the focus (target distance) in the camera, or do not change the position or rotation of the camera.
Depending on your scene and you want to come out focused have to do 3, 4, 5 etc render.
For example: I have this view side scene with 6 objects
and I want a final image with objects 2, 3, 4 and 5 focused, as the target of the camera is in order 2 to do I get focused only render the object 2 and blurred the rest.
Save this render as objeto02.jpg because then you’ll use it, change the values of the target to be in the object 3, you have a render and save as objeto03.jpg returns to change the values of the target to match the object 4 render and save (objeto04.jpg) and finally changes the values of the target to the object 5, has a render and save (objeto05.jpg).
In total you should have 4 images, remember that the more renders and make distances shorter target extending the DOF will be more accurate.
Download the renders to follow this tutorial and continues in step 2.
1-B.- Bracketing Focus desde tu cámara Reflex
It is advisable to have your camera set on a tripod fits all objects, it is recommended that all photos have the same shutter speed, aperture and iso.
You need to make several pictures with different approaches, for example I have the following composition in row 6 objects over closer and other spaced away, which I want are to focus from 2 to 5 (for this tutorial the object closer the camera is 1 and moreover 6)
approach each object can do automatically (if your camera allows it) or manually, just remember to change the focus, do not change neither the position nor the camera rotation begins to focus the object 2 Take a picture, then focusing the third object make him another photo, each object continues until 5. remember you do not have to change the shutter speed or aperture, or ISO.
In total you should have 4 images, transfer them to the computer and rename them (objeto02.jpg, objeto03.jpg, etc). Download photos for this tutorial and continues in step 2
2.- Upload images
Now what you need to do is stack of 4 images for this we will use Photoshop, this step is valid for other programs, but we do it in Photoshop as the editor best known images (in the end you’ll find a list of more programs that extending the DOF).
Open Photoshop and click on File > Scripts > Loads Files into Stack… menu, a new window opens, click the Browse button … looking 4 images, select them all and Accept.
In the same window brand Attempt To Automatically Align Source Images for the program to make necessary modifications to the respective (move, rotate, etc..) In the 4 pictures that fit perfectly for one over the other as it had been some movement between the box one image to another, whether your images come from 3d renders do not need to check this option.
Hit the OK button, the photoshop starts the process of putting the 6 images in layers one above the other.
3.- Stacking Focus
Now comes the stacking approach, select the 4 layers
go to Edit > Auto-Blend Layers… in the window that appears, select choose Stacking images and consistent color tones, this will make your pictures have the same shade of color, give OK.
Photoshop begins the melting process which takes very little. The end result photoshop creates a mask for each layer of each layer revealing his opinion just what is in focus.
As a final result the objects 2, 3, 4 and 5 are focused:
In step 2, if the Photoshop already open 4 images in individual windows on the Load Layers window can give the button Add open files and so they are automatically loaded into the window (it will load all the images in the windows that then have open).
If you want to expand your knowledge of the operation of the camera either Reflex or 3D cameras in the tutorial Parameters of cameras and photographic settings explained in more detail each of its major functions such as shutter speed, aperture, focal length, ISO, depth of field, and many tips explained with photos and diagrams.
Besides this focus bracketing technique, other techniques such as exposure bracketing used to create HDR images and Tonemapping in tutorial What is HDRi? and What is LDRI? I extend much more about this technique and its use to create images with high dynamic range.
Tips for users of 3D programs
In step 1-A instead of manually doing the render you can also make an animation with the target, ie every frame put the target with its modified value and rendering animation and every frame is saved as an image sequence. For example if I want renders focused object 2, 3, 4 and 5, at frame 0 put the target match the object 2, frame 1, the target match the object 3, frame 2 I put the target in the object 4, and frame 3 with target object 5, do the render animation from frame 0 to frame 3 and render the image of each frame is independent store, so I have 4 images saved at a stretch.
Tips for users of Photography
In step 1-B instead of making the focus manually there are programs in which you connect your camera to your computer via USB (on the computer you will see the frame of your camera type Live View), will you state from where and to where you want it done focus, then you put the amount of intermediate photos you want and voila, you shoot and the program does the sequence of photos focusing as you indicated. At the end of the tutorial I show a list of programs that do this process.
Here I show you a gallery with images from this tutorial and others as an example as well as some of the programs that make the series of photos automatically
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