Stacking

With Helicon Filter you can merge several images into one. Why would you do that? To extend the depth-of-field or to reduce noise or to get an interesting artistic effect.

Extending the depth-of-field

Blending several partially-sharp images into the one fully sharp is called "focus stacking". Focus stacking can give you an amazing depth-of-field which can never be achievied with one shot.

What do you typically do when you need bigger depth-of-field? You use small apertures. But at some point there comes lens difraction and overall loose of sharpness. And all the same, in some cases the small aperture cannot give the needed depth-of-field. You often face it in macro-photography, and always in micro-photography; the bigger magnification you use, the shallower depth-of-field you get. So, what to do? Use focus stacking! Focus stacking is a post-processing technique which completely solves the depth-of-field problem.

Now, how does focus stacking works? You prepare a stack of images, each one focused on different part of the scene. Then you open them in Helicon Filter* and merge the sharp parts into one completely sharp image. On the example below you can see how just two images can give you bigger depth-of-field than ever possible with one shot.

focus stacking sample focus stacking sample focus stacking sample
The flowering branches in the front are in
focus.		 The castle in the background is in focus. The two original images were merged into
the one, both the castle and the branches
are sharp here.

*Helicon Filter offers the basic focus stacking, if you want the advanced solution, then download Helicon Focus - a specialized program for focus stacking from Helicon Soft.

How to prepare a stack

Here is how you can shoot a stack manually:

  1. Focus on the front of the object and make a shot
  2. Rotate the focusing ring to focus a little bit further and make another shot
  3. Repeat the second step until the farthest part comes into focus

importantWe recommend to use a tripod to aviod the shifts, though small shifts can be processed by the program. We also recommend setting the aperture to your lens' sweet spot (the lens' sharpest aperture). In most cases, your lens’ sweet spot is two stops above its widest aperture. For example, if your lens' widest aperture is f/2.8, then its sweet spot is f/5.6; if the widest aperture is f/4 then the sweet spot is f/8. You can find more information about lenses' sweet spots on various review sites for lenses, such as www.DPReview.com, or else you can conduct your own tests.

Shooting a stack manually can be a cubersome task. But you can get it automated by using Helicon Remote - a program for tethered shooting. In such a case you connect your camera to a computer with Helicon Remote, set the farthest and the nearest focusing points and the program does the shooting.

How to process the stack

Select the folder with the stack. Mark the checkboxes for the images which you would like to merge. Go to the main menu and choose: Stack → Merge focused areas. That is all! Now you can save the resulting image.

Alternatively, you can mark the files, right-clcik to call the context menu and choose Merge focused areas.

Reducing noise

You can reduce noise by averaging several images of the same scene. Ideally, the camera should not move between shots.

Mark the checkboxes for the images which you would like to merge. Go to the main menu and choose: Stack → Reduce noise by averaging. Now you can save the resulting image.

lternatively, you can mark the files, right-clcik to call the context menu and choose Reduce noise by averaging.

Merging images for artistic purposes

You can achieve different artistic effects by merging and by averaging completely different or partially different images. Note, that the results of applying Merge focused areas and Reduce noise by averaging will differ.