This is good stuff. It took me a lot of test shots and experimentation to finally figure out that you don't need to save Focus Point B by hitting the display back button. That just creates confusion and flips you to another earlier screen.
Glad you started a new thread on this. The other threads were getting loaded and confusing.
Here are some notes that I jotted down in my notes taken from all the other threads this past week, mostly stated by Jim, SrMi and Theia.
……………………………………………
Jim: Greg, do yourself a favor. Use Helicon Focus vs PS for focus stacking. It is much easier and does a great job and works well as a LR plugin. (So I bought it)
Jim (on step size decisions not on auto): With Fuji Focus Bracketing, focal length and distance don’t affect the step size you should use. The subject matter and the application do. Focal length and distance affect the number of shots you’ll need.
SrMi (responding to Greg's question about how LR can export either tif or DNG files to Helicon focus, and Helicon Focus can then render them with a tif result, or DNG result. But the DNG it renders after the stack is not a true raw file as we think of raw files, like a raf file coming out of a Fuji camera and into LR.
SrMi said: Let's talk about three formats - DNG (raw) output of the Leica Q2, linear DNG output of Helicon, and TIFF. The DNG (raw) output of Q2 is not demosaiced. X-Transformer, LR, and C1 all use different demosaic-engines. Once a raw file is demosaiced, you cannot run another demosaic tool on them, so you are stuck with whatever LR/C1/X-Transformer has done. The good thing about (linear) DNG output of Helicon Focus is that it has not been mapped to a color space, has not been white-balanced, etc. You can transform any raw file into a DNG without demosaicing. But, to process the files, Helicon Focus must demosaic the files first. On another note, make sure that you always have the latest Adobe DNG Converter installed. Helicon Focus does not check if it is out of date and Adobe does not include it in the LR / PS updates.
Jim: Helicon demosaics before stacking and writes out a demosaiced DNG.
Jim (explaining to Greg about DNG files): a DNG is not necessarily a raw file. Some raw files are DNG's. Some DNGs are not mosaiced. The key element here is that the DNG remains scene-referred. (I don't know what scene referred means)
Greg said to Jim and Jim agreed: Processed demosaiced output from processes like Helicon have to be a TIF or JPEG or demosaiced DNG (something not-raw).
Jim, explaining to Greg what a Step Size really is:
The red circle on the diagram indicates the blur circle in the sensor plane for an object in the near plane when the camera is focused on the middle plane. Let’s call that the single-step-CoC. When you use focus bracketing, what controls its diameter?
The surprising answer is: just the step size. That’s right. Not the focal length of the lens. Not the distance from the camera to the subject. Not even the f-stop. The camera takes care of all that. You don’t need to understand how the camera manages that feat to successfully use focus bracketing, but for those who are interested, I’ll explain now. The diameter of the blur circle is the shift in the image space focal plane from the sensor divided by the f-stop. The subject distance doesn’t enter into the calculations, since we’re working in image space. The focal length of the lens doesn’t matter, either, since it is handled by considering the f-stop. So all the camera has to do is look at the f-stop and the step size, and move the image side-focal plane so that the blur circle doesn’t change when you change the f-stop.
The beauty of this is that you can think of the step size strictly in terms of the blur circle that you are willing to have."
SrMi to Greg: I think once you understand what CoC means, you would also understand how step-size works. Let's say you manually shoot a two-shot focus stack, with a near focus point and a far focus point. If the two focus points are far enough apart, you will notice that the focus stacked image (after Helicon) contains a blurry area between the two points. The step parameter specifies how blurry that area may be.
The blurriness between the two focus points depends on the DOF at near and far focus and the distance between the focus points. The camera changes the focus only so much that the specified blurriness (as defined by step parameter) remains constant. If the step size parameter is unchanged and you close the aperture, the focus will be moved in larger 'steps' because of increased DOF.
Greg says to SrMi: Yes, that is another way of saying exactly what I said and what I have thought from my very first post. The step is changing the plane of focus either a tiny bit (one) or a larger slice (10) and at ten, you run the risk of having some OOF area between shots because the "slice" between shots has widened, or the plane of focus has moved on forward beyond the point that is in focus at that aperture.
Jim responds to Greg's above statement. Jim (to Greg) So far so good. But what you're missing in your other posts is that the aperture, focal length, and subject distance don't affect the blurriness of the in-between shots subject matter.
. Greg suggested that I start a new thread summarizing it.
