Saturday, October 22, 2022

How It Stacked Up

 



© 2022 Luke T. Bush


As you can see from the above photo everything is in focus despite the great magnification.  When doing close-up/macro photography only a narrow area is in focus.  Photograph the front part of a small subject and everything behind that point is blurry.  There is only so much you can do with one shot.  The focus depth could only be 2 millimeters.

But what if you could focus at different points, creating in-focus layers and then combine those layers into one sharp image?  This can be done with a focus stacking program.  This program goes through the layers, selecting the sharpest parts to produce an image with good focus depth.

The set up I used was the camera and macro lens on a tripod mounted focusing rail.  By turning the rail knob you carefully move the camera and lens forward to image each layer.  When your depth of filed is measured only in millimeters it takes time to produce the needed images.  The series might be 30, 60, 100 or more images.

With great magnification the tiniest movement or position shift can cause misaligned shots that result in an unsharp result.  During processing all the images have to be closely the same for proper alignment.

The camera and the subject stayed still but the final image was a bit blurred.  Going through the series of images I noticed that after the fifth shot that some of petals lifted up on the right side (my POV).  See the comparison images below.  Maybe the petals raised because the flower was drying out.  Even though petals had repositioned themselves a tiny fraction of an inch it was enough to ruin the stack.

I was lucky I was able to get a good stack by starting at the point after the petals had popped up.

Sometimes photography is a lot more than taking a quick snap.



2 comments:

Anonymous said...

Were you applying light (also could create heat) to the subject, that may have caused the reaction?

Luke T. Bush said...

I was using LED bulbs that are a lot cooler than the old tungsten finger burners.