Makrak prototype

The Makrak is a tripod attachment that allows you to screw the camera forward and back in small increments. One full turn of the knob advances the camera 1mm, so a quarter turn advances 0.25mm.

The object is to take stacked images of macro subjects (hence the name: Makrak = macro rack). The stacked images are then processed and merged together into one image with a much deeper depth of field than is normally attainable with one image.

At maximum macro distances, the depth of field is actually less than 0.5mm, in fact, closer to 0.25mm. This is why new comers to the macro world, having spent hundreds on a new macro lens, are usually bitterly disappointed with their first batch of images, expecting to see a crisp image of the spiders eyebrows and what size clogs he is wearing, all in one image.

So why stack? - I wanted to show in an image of what the human eye sees. The human eye actually only sees the equivalent of a small group of pixels. You can test this out yourself. Concentrate on the first letter of a long word and you cannot see the last letter.

The eye scans the subject, the brain processes and merges together the information and presents your memory with a stacked image of the whole subject. Same thing really!

Yesterday's image of a shield bug was a stack of ten images taken at 0.25mm intervals, giving a depth of field of 2.5mm, just enough to cover the head and shoulders, allowing you to see the facets of the compound eyes and the dimpled texture of the thorax. Do a direct comparison of yesterday's with the same insect shot on the 7th December and you will clearly see the difference that stacking makes.

I haven't cracked it yet. Still more work on the Makrak technique required and the Photoshop CS5 processing needs a lot more practice, but I am already pretty close and very happy with the Makrak design.

There are racks on the market, but out of my price range at several hundred dollars and way too big. Mine has a maximum travel of 33mm which is still huge, unless you want to get involved with 130 image stacks!

As you can see, I have constructed the unit from available materials that I have the tools to process. Lots of wood and screws, a couple of stainless steel rods for sliders, a standard threaded rod for the movement, a couple of 6mm nuts and six bearings used as guides.

The unit is solid and there is no slop or play. The camera is as secure as it ever was on the tripod, as I have used the same attachments. Once I have sorted out the technique, I will write a document on stacking and make it available.

Dave