Digital Techniques - Focus Stacking

Focus Stacking? What's that then?
Well read on for more details and how you can get incredible close ups and avoid the limitations of your lens Depth Of Field.


Several months back a posting was made on the Fuji S5700 Users Group on Flickr concerning focus stacking by Flickr member Mauritius100.

I had an attempt at this, (early on in my digital adventure), without much success but finally came across a couple of pieces of free software that makes it all so easy.

The first is Picolay which is small and stable enough to run on any PC or laptop. It will even run off an USB memory stick!

The second is CombineZM which was the software that I actually chose to use.

The image below shows what we're trying to achieve.



On the left is what my digital camera, (Fuji S5700), could manage with it's aperture wide open at f3.5 which will give the shallowest depth of field. The middle image is the best that could be achieved with the smallest aperture, (f13.5), to achieve the greatest depth of field. The image on the right shows what can be achieved with focus stacking - pretty impressive if you ask me!

The method used is a little bit like HDR generation but rather than changing exposure we change the point of focus and use the software to 'stack' all the focal points together.

The following picture shows the images we had to obtain to perform this.



The image top left shows the focus set to the nearest end of the paper clips, that moves on until the final image at the bottom right with the focus set to the furthest point. (You do need to use a manual focus option to achieve this.)

I used the 'CombineZM' software to stack these all together to acieve this final output.



As you can see everything now appears to be in focus!

It is quite a remarkable technique and I've had fun using this method.

You do need to use your camera in manual focus mode and it can be quite tricky to see if you have moved the focus point on far enough with just an LCD for reference.
You also need to ensure the lighting conditions remain static and that your camera is in manual mode to keep the images to the same exposure.
A tripod was used throughout to keep the images aligned. (The software allows realignment, but it's far easier to get it right first.)

Well, that's pretty much it - worth giving it a go and the software does makes this really easy to do.

You don't just have to use it for macro or close up work either. Try it out with near and far focusing and make that foreground flower sit over the romantic background building or any number of things where a better depth of field would be advantagous. Although we all tend to concentrate on 'blurry', oops sorry 'bokeh' style pictures;)

Easier than it looks and quite impressive to use. Oh, and that picture at the start is a young cellar spider, Pholcus Phalangioides, and it's head is less than 1mm across! This method used a macro 'rail' so that the whole camera was moved through it's plane of focus rather than refocusing. Much easier to do!

Have fun!