One of the challenges of close up work is the very limited depth of field (i.e. not much is in sharp focus). You can increase depth of field by stopping down the aperture to f11 or f16, but depending on how large your subject, you may only have a few millimeters in focus (less than a mm at high magnification).

One way round this depth of field limitation is to use “Focus Stacking” software to get extended depth of field. This is where you take a series of shots of a scene, focussing each shot slightly differently until you have covered the whole area you want in focus. The software combines the images into a single image with much greater depth of field than the original shots.

CombineZM

I decided to use CombineZM - a free image stacking software product from www.hadleyweb.pwp.blueyonder.co.uk There are other products that do the same thing such as Helicon Focus.

So how did CombineZM work? To find out I tried a quick test using a Pentax 50mm lens with a 20mm extension tube on a Pentax K100D digital SLR. The camera was on a tripod. I took 15 images f8 (probably didn’t need that many images).

I installed CombineZM and using the default settings stacked the 15 images. You can see the result in the shot below. It looks quite promising -the whole “scene” is in sharp focus.

For comparison, below is one of the individual shots from the camera before stacking.

For nature photography, this technique could be useful for plants or other objects that do not move. For moving things like insects it wouldn’t be much use though. If you find a bug that stays still for long enough it would work fine - maybe a dead one for practice

I’m interested in it for macro work, but it looks like it could be used in a much wider range of photography.