Focus Bracketing to Find the Best Overall Image in a 3D Scene
Related: focus stacking, focusing, Hasselblad, Hasselblad medium format, Hasselblad mirrorless, Hasselblad X2D 100C, medium format, Michael Erlewine, reader comment
re: Hasselblad X2D 100C: Best Focus Bracketing Support Yet of Any Brand?
re: Hasselblad X2D 100C: Step Size for its Focus Bracketing Feature
Reader Michael Erlewine writes:
I am trying to understand and utilize what your wrote of the various kinds of focus stacking.
I understand the first (to infinity) and the second (from far to near), yet I still don’t understand the use of the Symmetric mode.
I would tend to use the second mode, and with my technical camera I lock the most distant part of the subject I want in focus and make my focus rail have a hard stop there, leaving the rest for bokeh. It’s great that you did the work up you did and I appreciate it. Now to fully understand it and put it to work.
DIGLLOYD: as I am thinking of it, Symmetric mode would be best used for a focus bracket for the purpose of selecting the best sharpness “landing zone” for the subject.
Make your best guess at optimal focus placement, then shoot with Symmetric with at least 4 total frames. One of them is likely to be significantly better for sharpness cutting through the subject in a better way.
The bonus of doing this is you could decide to do a “short stack” if conditions allow, or you could simply select one single frame as the best of the lot. You can’t lose.
Example
Consider this image from Earth Shadow Rises over Aspen.
Where exactly should you focus in order to have maximum foreground sharpness without giving up sharpness to the storage shed? Depth of field is asymmetric (more to the distance), and the lens could have a little focus shift and/of field curvature, and the subject spans a significant neaer/far distance.
All these things together make it difficult to be sure of the zone of sharp focus on such a complex scenes, including the visual impact of what is unsharp and by how much.
Indeed, the lens here *does* have a slight forward focus shift. I did pretty well with my focus placement (see the full aperture series), but it is likely that some slightly different focus placement would have produced a better overall result.
Fujifilm GFX100 II + Fujifilm GF 55mm f/1.7 WR @ 45.3mm equiv (55mm)
ENV: Colorado, altitude 8400 ft / 2560 m, 42°F / 5°C
RAW: Camera VELVIA, Enhance Details, LACA corrected, WB 5000°K tint 18, +30 Shadows, +20 Whites, +10 Clarity, AI Denoise 10
[low-res image for bot]
