jbmauser Loc: Roanoke, VA

you can focus on the near point and then by turning the lens barrel move the focus back and repeat then stack. Or you can focus on the near point and move the entire camera on a rail closer to the subject. Will the result be the same or will the rail introduce a change in perspective? Will stacking software handle each stack the same?

Mark Sturtevant Loc: Grand Blanc, MI

It doesn't matter which way you turn the focus barrel as far as the stacking program is concerned. I think you can also reverse the order of the pictures in the program.

ecobin Loc: Paoli, PA

Typically you move the rail in tiny increments (microns) - therefore, any change in perspective would/should be imperceptible. Great question!

sippyjug104 Loc: Missouri

Excellent question and both methods work well. Adjusting the focus of the lens is much inline with what in-camera focus stacking does when using AutoFocus compatible lenses. Helicon offers a "automated focus tube" for cameras that do not have that feature built into them. It is a fantastic tool for both staged sessions and shooting in the field.

Moving the camera, or the subject, in fine increment for each shot does change the perspective between the images in the stack. The processing software does align them so the effect is aligned however, there is cropping that occurs in the software's processing so in deep stacks not all of the view seen in the initial shot is seen in the final produced single image.

jbmauser Loc: Roanoke, VA

Thanks all, I am working up a presentation for my photo club and the theme or slant will be getting into Macro on the cheap. featuring tubes, lens reversing adapters and diopters. focus staking will not need a rail. They can all put their toe in for a few hundred bucks. If the bug bites them they can gear up.

Mark Sturtevant Loc: Grand Blanc, MI

Close up focus stacking, as opposed to super hi mag stacking like what Sippy does, does not require dedicated and special equipment. Its pretty easy to just mount the camera on a tripod and move the focus ring a small increment for each picture. Check early to confirm that the focused bits in each picture are overlapping so the eventual stack comes out in continual focus.
Its more likely that the focus ring method will ensure minimal parallax shifts, since the lens moves in and out perfectly perpendicular to the sensor. Doing a stack with a focus rail to move the camera might add some additional parallax shift. It can work, but one has to be careful in the set up.
The stacking software works to match the sizes of the pictures (the sizes change slightly in each picture), but it will struggle to line up the parts that have a skewed type of parallax shift. So I've thought that the focus ring method is easier to pull of then the focus rail method. But even a fairly clean focus stack will commonly have artifacts in the final picture. At least that is the case for me. Then its time to use the cloning and healing brushes in Photoshop or some other such program.