Re: Focus versus Rail stacking Poll
1
xpatUSA wrote:
AntonJA wrote:
xpatUSA wrote
Asking for a quick poll as to which is "best":
"Best" by what evaluation criteria?
"Best" for what?
Yes, I am well aware that "best" is loose terminology which I normally hate. However, I am not well up on the minute details and methods of close-focus stacking, so I deliberating left it vague.
Perhaps you could tell mewhat those evaluation criteria are, or what?
I think the criteria vary from person to person. Mine have led me to an approach which hasn't been mentioned here yet, which is to use video. I use Panasonic's Post Focus facility to capture a video from which I extract stills to stack. My criteria for preferring this approach are as follows, relating to botanical close-ups. (I have not yet had great success with stacking for invertebrate subjects, but there again I haven't put much effort into it as single-image captures seem more suitable for my invertebrate subject matter and shooting conditions, so I'm not highly motivated to spend time on stacking for invertebrates.)
1. It is easy to do the captures, producing a reliably well-spaced set of images to stack. I use aperture priority mode and as for stills I select the aperture, ISO, and exposure compensation (for which I have a free choice as long as the shutter speed is 1/30 sec or faster). I also select the framing of the scene. At that point I press the shutter button and the camera does the rest, moving the focus from the nearest thing it can focus on to the furthest, at 30 frames per second. It automatically adjusts the speed of the movement from front to back (and hence the distance between consecutive frames), taking account of aperture (and hence the DOF of individual frames) so as to always produce frames that are close enough for stacking.
2. It is quick to do the captures. If I stack, say, 45 frames then the capture of those frames was done in a second and a half. This matter to me because
- I prefer to work hand-held, for creative reasons, and sometimes I have to work hand-held anyway for scenes that are not tripod-accessible (occasionally working one-handed with arm outstretched), and
- I live in a breezy location and often have no choice but to work in breezy conditions (plants can change during the course of a day and light can change in seconds; waiting for another day with still air is not a practical option). On a breezy day this means waiting for the subject's movement to slow down enough for a stacking capture to work well enough to be usable. It is much easier to happen upon, say, 2 seconds of calmer air than the much longer period that would be needed for other techniques. The fact that the captures are so fast to do also means that it is practical to have repeated attempts to increase the chance of getting one that works.
3. I can use light and flexible kit with this technique. I generally use a small, light macro lens, but it also works with a longer reach with a small, light telezoom lens. I typically use maximum aperture to maximally blur backgrounds. The maximum aperture is smaller with the telezoom, and so the aperture-based background blur is less, but when using it at the telephoto end, which I do, the background compression is greater, which increases the background blur.
4. The pre-stacking preparations are easy. I simply have to drag the video into Helicon Focus, which automatically extracts the JPEGs and aligns them. I can then delete the frames I don't want to use. From then on the stacking is the same as with any other capture technique.
5. File handling is easier than with other techniques. Instead of having to deal with multiple, possibly several tens of, image files for each capture set, I have a single file to handle for operational and archival storage.
6. I have used the technique with 4K video, but now use 6K video. This gives 18 megapixel JPEGs to work with (more than the more usual 16 megapixels for a full sensor image from micro four thirds cameras), which is sufficient for my purposes, which is to produce 1300 pixel high images.
7. Image quality seems ok for my purposes (subject to the usual caveats about personal taste, image size, viewing distance, visual acuity, tolerance for flaws and stacking issues, when they arise, and the extent to which they can be resolved sufficiently well to produce a usable end result in an acceptable amount of time).
In case you have not seen examples of this technique before, here are some examples captured in our garden, the first four captured using 6K with a Panasonic G9 and Olympus 60mm macro earlier in the year, the other four captured before that using 4K with a Panasonic G80 and Olympus 60mm macro. The first one in each set of four is a combination of two stacks, the others are single stacks, all of which according to my records appear to have not been retouched using Helicon's retouching facilities (all eight stacks were passed to Lightroom for normal post processing).
#1 32 6K frames stacked
#2 20 6K frames stacked
#3 42 6K frames stacked
#4 28 6K frames stacked
#5 201 4K frames stacked (I think my hands may have been resting on a low wall for this one, rather than working unsupported hand-held as I think all the others were)
#6 40 4K frames stacked
#7 35 4K frames stacked
#8 17 4K frames stacked
