cbtsam wrote:
I posted this in Close-Up Photography, and only got one response, so I'm trying it again here, with some extra questions.
I have read about two different tactics for collecting exposures for focus stacking. (I) In the first, the camera stays in one position, and the lens is focused on a different point in the subject for each exposure. (II) In the second, the lens focus doesn't change, but the camera is moved slightly closer or further for each exposure, so that each exposure still features a different focus point.
I use an AF Micro Nikkor 105mm f/2.8 D lens. Like many (all?) Micro Nikkors, the focal length actually changes as focus changes, particularly as one approaches 1:1, so the perspective changes as the focus changes. Similarly, as one moves the camera closer to the subject, the perspective shifts a bit. I assume that the stacking software takes all of this into account.
My first question is: What reasons (if any) are there to prefer tactic (I), with the stationary camera, over tactic (II), with the moving camera, or to prefer tactic (II) over tactic (I)?
This has become a more interesting question with the appearance of the D850, which provides an automated feature for tactic (I), but not for tactic (II).
A second question concerns the number of exposures to use. In general, does the process work better if I take more exposures at different focus points very close together, or fewer further apart?
A third question concerns the results I've gotten using Photoshop CC to combine images. While I generally do get sharp focus from front to back, I also get some edges that are not well-formed. Is this the limitation of the Photoshop algorithms, or something rather common in focus stacking? (I've gotten these edge problems with single flowers, using a combination of some twenty odd images.)
Finally, a fourth question concerns education recommendations. Obviously, I need some more education in this area.
Thanks in advance for your input; I'm looking forward to it.
I posted this in Close-Up Photography, and only go... (
show quote)
I use the rail to position the camera precisely. After that, the focus ring to adjust focus. Olympus cameras have added a focus bracket function that automates the focus stepping; and with some lenses will even do the stacking to produce a single image.
If you are going to adjust the focus manually, I recommend a focus puller. Even a simple add-on lever will make adjustment easier and more precise.