I am having lots of fun with some flowers and focus stacking using the fabulous 85mm PC-E lens on my D800E. I process in LR4 and PSCS6. I recently purchased a RRS macro rail and now am wondering whether it is demonstrably better to use the rail and move the camera without refocusing or just refocus from the near point to the far point of the object.
Here is my current technique. I mount the camera, with it located at the rear of the rail, and focus on the near point and make an exposure. I then slide the rail to the far point for an approximate focus and then fine focus on the far point using the screw to move the camera. Once I have the far point focus, I make an exposure and move the rail incrementally without moving the focusing ring on the lens, back until I get to the close point. All focusing is done with live view and a magnifier for accuracy. I focus actually only on the near and far points. I then bring the 10-12 images into Lightroom 4, correct the first image, synchronize the rest, and import as layers into Photoshop. I then select all the layers, go to edit-auto align, then edit-autoblend and after I have reviewed it and looked at it carefully, flatten what is often a 3-4GB file. I always have to do some cropping because there are always fuzzy edges.
Before I got the rail, the technique I used was to focus on the near point and then just incrementally refocus until one gets to the far point, and then do the import and processing as above. I have taped a piece of paper to the lens barrel with the near and far points marked so I know where to go as I move the focus. I am happy with the results from both, but wonder if I am missing or misunderstanding something.
I'd greatly appreciate comments and/or suggestions regarding these approaches.