Monday, March 28, 2016

In Search of Focus - Focus Stacking

Like most photographers, when I have a shot that is in great focus, I have to wonder if I really had any part in the process.  Sure, most shots come out well.  But when one is right on the money, it does stand out.
Especially that pesky Depth of Field (DOF) thingie that can ruin a great shot.  
I started looking into photo (focus) stacking.
This is a process that starts at one focal point, takes a photo, then moves to another focal point and takes a picture and repeats the process as much as necessary.  It may be two shots.  It may be hundreds of shots.  The trick is to get some point of the shot in perfect focus.  And let the other shots do the same.
And then of course, some software package has to find all those points that are in perfect focus and blend them together.
Today's project is with Helicon's Focus and Remote.  (  I did some research on photo stacking software and stumbled on this package.  I'm also looking for a remote package I can run off of a tablet to run the camera and this suite had all the pieces.  So, I'm now on the 30 day trial.
I have a C5A/B model that will be the perfect subject for this test.  It is about 20 inches long and has some detailed markings.  It will do the trick.
The particulars are 48mm, f/11 and 1.6 seconds.  Put that in a DOF blender and you get a DOF of about 6 inches.  One other difference, the original shot is a RAW image, and the processed image is JPEG.  But the point of the exercise is the focus difference between the nose and the tail.
Conventionally I have lots of options.  One is go back to the DOF calculator and find a setting for 20 to 24 inches.  But I may not like what it tells me.  I know for this lens at 50mm, f/11 will get me better focus.   I could play with ISO and speeds.  Blah.
If I were to take a conventional shot, with the focus point on the nose this is what I get.
I've left the image snap shots at 1:1 - there are no reduction issues.
The unaltered image.

OK, looks OK?  Yea, but.
Here is the nose, a bit closer up.  (Remember, this is the start of the focus points.)

The nose is in focus.  There is some detail in the lines.  (Also look at the blue background, a towel.  Just a bit out of focus.  It is a total of 36 inches behind the nose.  Remember this.)

Here is the tail.

Enough said.

With the photo stacking:  This is a stack of 7 shots.  To be honest, the first two shots had absolutely nothing in focus.  But that's OK.  I'd rather have too many than not enough.

Here is the stacked picture:

Well, for me pretty much instantly I can see the background is all in focus.  yea, the model is in focus as well.  let's go to the close ups.

The nose:

The nose is pretty much the same, but wow, look at the blue towel.  It looks like there is a bit out of focus on the left.  There's a blending issue.

The Tail:

The tail has a lot more definition.  Looking at the flag painted on the tail, it has some definition.  And again, the blue background has much more definition.

Google focus stacked photos on the web.  There are some pretty interesting shots out there.  Most of the ones that catch my eye are done with macro lenses, something that is missing from my inventory of equipment.  

This was interesting project.  And for the next 29 days, it won't cost me a thing.

1 comment:

  1. I have been thinking of it. One of the local contests mentioned that it is acceptable, and I had NO idea what it was. Glad to see an example.