In the second of my series of tutorial articles looking at stacking software, I take a look at focus stacking with Helicon Focus from Helicon Soft. Again I am just going to let the software do all the work, the only tweaking being some dust and noise adjustments on the final image which I cropped slightly round the edges due to the odd artifact showing and to improve the image composition slightly. All that done in Photoshop.
I downloaded their latest demo software which you can use for 30 days free, with it fully functioning apart from the retouching tab ( adds a watermark if you use that bit). The version I used was version 5.1.19 (14/09/2010). The download was fairly quick as the size was about 28meg to download. I installed on my windows 7 64bit OS without a problem.
I took a series of 6 weevil shots on a focusing rail earlier in the year (May to be precise) at F9 on my Canon MPE-65mm Macro Lens. To give you an idea of the range of different focus the start and end shots from the 6 shots used are shown below. (NB to see some images bigger or just cycle through them click on any of the images).
So on with the tutorial. First of all we need to load the files that we want to get Helicon Focus to attempt to stack for us. So on starting the program I selected File -> Add new items from the drop down menus (see image below) and then loaded in the 6 images to be stacked.
Now with the files imported into the software (you can see thumbnail previews in the right hand side window, and select / deselect them if you wish), we need to switch to the “Parameters” tag to select the options for stacking the images.
Once we are on the parameters tag it is possible to re-order the images, and select two different methods for stacking images and some options to fine tune the stacking. I generally prefer the results from method B, and this is what I have used for this tutorial.
The help text for Helicon describes the options as follows
Method A computes weight for each pixel based on its contrast. Then all pixels from all source images are averaged using their weights.
Method B finds the source image where the sharpest pixel is located and creates “depth map” from this information. This method requires that images are shot in consecutive order from front to back or vice versa.
If you plan to create 3D model from your stack, make sure you are making roughly equal steps between shots.
Method B usually creates less noticable halo effect around contrast edges. There is no stict rule which method is better. It depends on the image and we recommend to try both of them.
If your image has fine details, most probably low level of radius (3-6) would give the best results.
If the image consists mostly of the coarse lines, then you should try higher values (10-15).
The Smoothing slider defines how the focused parts are combined. Low level produces sharper image, but transition areas may have some artifacts. High level of smoothing will result in a bit blurry image without visible transition areas.
As I previously mentioned, I used method B, and left the sliders at there defaults and just clicked the Run button to start the stack. As the stack processes you can see the current image it is using and (when using method B), a depth map being built in the bottom window. (See below).
Once the stack is complete, (it took about a minute for this 6 image stack), the image can be previewed at higher magnification, text added, and some retouching done if wished. I added the black text, then selected the Save tag (shown below), and saved the output image. Note it is possible to do several stack runs and tweak the parameters from the same set of files. The different results are stored and can be individually saved later (useful if you want to play about with the options to get the best result).
The final result after a quick clean up of dust ,level tweak, and minor crop in photoshop from the Helicon Focus stack is shown below. I have to say I am impressed with this software, though have yet to purchase it.