Why Use Focus Stacking?Have you ever tried taking a real close-up picture of an object (like 30cm away) and the object does not turn up to be sharp from front to back due to the Depth of Field (DOF)? Changing to a smaller aperture is unlikely to help much as the distance away from the subject is too short. Try moving further away and end up getting the object to be smaller in your frame which is not what you want.
This is when Focus Stacking is useful. Focus Stacking technique involves taking multiple shots from the front to the back of the object where each shot is manually focused at the different points of the object i.e. from the head to tail of the object. Each shot should be taken at a consistent distance apart using the same aperture and and the distance apart should be within the depth of field.
These multiple images are then taken into photoshop, stacked and blended together to give a perfectly sharp image from front to back.
What I've explained is just a summarized version, and you should really take a look at Forrest Tanaka's video to fully understand it - he has illustrated it so clearly that it is well worth the time watching. (Note: There is also another focus stacking technique slightly different from what was mentioned above that he has also illustrated in his video.)
My ResultsToday, I started off with a small object (i.e. a dutch wooden shoes) which is about 10cm in length. Given the a 100mm lens on my 5DM2 and focusing at a distance of about 30cm on F11, my depth of field is about 4cm.
True enough, I tried focusing in the middle of the shoe and both ends of the shoe is out-of-focus (blur). Given a 4cm depth of field, this means that I would probably need 3-4 shots covering the front to the back of the shoe. Being a "kiasu" Singaporean, I took 10 shots starting from the head of the shoe with 1cm apart each shot to ensure that my depth of fields are overlapped for every shots.
With the 10 shots, I went on to stack and blend them using Photoshop and I get a perfectly sharply focused dutch wooden shoes from head to tail. It was cool ^.^
[Updated on 19-Oct-2013]
Please visit http://jefzlim.smugmug.com/Studio-Works/Still-Life to see the high-resolution picture ...