Problem with macro focus stacking

[rpcrowe]

I did this focus stack using twenty images shot with my Sony 7Diii and Venus Optic 60mm f/2.8 2:1 Macro Lens. The camera/lens was on a focus rail and I shot the images at f/8. I changed the focus plane with the wheel of the focus rail with the front of te hook in focus for the first image. The wheel was turned approximately the same for each shot... I used a 3-second delay in shooting each image.

I opened the images using Adobe Bridge and Adobe Camera RAW and did stacking in Photoshop 2020.

The Wooly Bugger fly is a bit over 3-inches (abt 75mm) long.

Everything looks O.K. except for the area around the barb of the hook...



My Photoshop 2020 stacking process was this:

1. FILE>scripts>load files into stack
2. SELECT>all layers
3. EDIT>auto blend layers>stack images>seamless tones and colors>content aware fill transparent areas

What might the trouble be?

I did this focus stack of an inch and a half long (abt. 40mm) Royal Coachman Streamer at f/11 with 9-images. I eyeballed the focus as I rotated the wheel of the focus rail using focus peaking...



There doesn't seem to be a problem with this one...

[Stagecoach]

It could be one of these Richard;

a) Using the rail as opposed to the lens barrel adjustment increases perspective variation which 'may' be too much for PS to deal with. This is something more aparrent with deeper depth subjects.

b) You missed some slices, (this noticeable in the feathers which could also be due to a) above).

[ST1]

I wonder if the issue is caused by a combination of your use of the rail and choosing f8.
Providing you still have the images that you used to create the stack, it may be worth downloading the free trial version of Zyrene to create a comparison between its handling of the stack and this one from PS.

Link http://zerenesystems.com/cms/stacker


Sent from my iPad using Tapatalk

[DanK]

Richard,

I don't stack with Photoshop, so I can't say much about the software end, other than that I believe it uses a depth mapping algorithm, which is somewhat more prone to halos than at least one other alternative.

However, I don't think you have a software problem. I also don't think it is directly an effect of using a rail.

If you look at the image closely, you can see halos scattered across the entire image. For example, there are some next to the feathers at the top and the far right.

This looks like motion to me: more movement between frames than the software can manage. Normally, I would guess subject movement in the case of fine materials like this. I sometimes get this with flowers--the movement in adjusting the camera is enough to cause the fine parts of the flower to move. However, the fact that you have a halo by the hook suggests that it may also be the camera itself that moved, perhaps unwanted motion when you adjusted the rail.

Re focusing with a rail: the problem with a rail isn't perspective variation per se but rather movement of the entrance pupil. You can get an explanation here, https://www.youtube.com/watch?v=mzVD95-9YOU, from roughly the 5 minute to 10-minute marks. The section starts with two composites that he created using a rail, one with Zerene DMap, which should be somewhat similar to Photoshop, and one with PMax. You'll see that both composites are pretty much OK. The problem that got the poster going was that the two composites didn't line up with each other.

Somewhere in the video there is a generalization from Rik Littlefield, the author of Zerene, who explained all of this to the poster: in general, if the subject is bigger than a raisin, you are better off adjusting focus with the lens helicoid (turning the barrel) than with a rail. This is why I have repeatedly responded when people have offered the advice that to do stacking well, you have to buy a rail. You don't. I have a fairly expensive rail (a Kirk) which I use only to help me get the camera positioned for the first shot. I have never used it for changing focus between shots.

Tiny objects are a whole different kettle of fish.

Dan

[xpatUSA]

Pardon my ignorance but, in focus stacking, is image alignment not available?

By image alignment, I mean the type where control points are found and aligned such that individual images are distorted so as to remove any movement/perspective differences.

Personally, I have used command-line align_image_stack.exe (HugIn, Panotools) prior to any stacking action (Enblend, Enfuse, etc). I rarely use stacking of any kind though. Just don't have the patience ...

[DanK]

Yes, but movement may exceed its capabilities, and irregular movement--movement of one part more than another--is problematic.

Pardon my ignorance but, in focus stacking, is image alignment not available?

By image alignment, I mean the type where control points are found and aligned such that individual images are distorted so as to remove any movement/perspective differences.

Personally, I have used command-line align_image_stack.exe (HugIn, Panotools) prior to any stacking action (Enblend, Enfuse, etc). I rarely use stacking of any kind though. Just don't have the patience ...

[rpcrowe]

This is a single shot at f/16 with a 1:2 ratio

I like a blue background better than a gray background...

Same 1:2 ratio...

[Geoff F]

Pardon my ignorance but, in focus stacking, is image alignment not available?

By image alignment, I mean the type where control points are found and aligned such that individual images are distorted so as to remove any movement/perspective differences.

Personally, I have used command-line align_image_stack.exe (HugIn, Panotools) prior to any stacking action (Enblend, Enfuse, etc). I rarely use stacking of any kind though. Just don't have the patience ...

Yes, Align Images is always part of my workflow. I assumed Richard simply forgot to mention that step.

Looking closely at the feather lines there is quite a bit of misalignment and broken lines.

I find Photoshop does a good job with larger areas but can fail to select tightly to the little bits so I often have to do some messing around with the masking layers.

[DanK]

Richard,

you have a bunch of sensor spots, more obvious with the gray background. I count more than half a dozen.

The more I look at this, the more I suspect motion. Normally, halos arise from parallax, when the edge of a near surface is a substantial distance from the next part of the object. here there is nothing but the background behind the parts that are haloed.

Dan

[xpatUSA]

Originally Posted by xpatUSA Pardon my ignorance but, in focus stacking, is image alignment not available?

Yes, but movement may exceed its capabilities, and irregular movement--movement of one part more than another--is problematic.

I see. If that is the case, perhaps the stack should be trashed - as one might do if, for example, an image were so far out-of-focus that sharpening doesn't fix it.

Or one could seek a "better" blender ...

Command-line alternatives offer many more and wider options than the dumbed-down apps in which they are embedded, but they do tend to hurt the brain.

[DanK]

One solution, if one or two images are off, is to stack by blending parts of the images manually. I've never tried it.

I see. If that is the case, perhaps the stack should be trashed - as one might do if, for example, an image were so far out-of-focus that sharpening doesn't fix it.

Or one could seek a "better" blender ...

Command-line alternatives offer many more and wider options than the dumbed-down apps in which they are embedded, but they do tend to hurt the brain.

[Jon Lip]

I have eliminated this problem altogether since I bought an Olympus camera. It has the ability to do in-camera focus stacking. Therefore, there is never any need to touch the focus barrel OR to use a rail. Once it has been set up with the number of shots (up to 999) and the distance (how far to focus from 1/2 inch to infinity) and the required DOF number, (I use f/8.0) once the shutter is pressed, it does the rest by itself! I then load a focus stack into Serif Affinity Photo and it does all the alignment and focus stacking and produces a single image (that can be edited by individual frames) All done - no probs. Why not give not a try?

[Jon Lip]

Richard - I agree with DanK there are definitely sensor spots

[DanK]

I have eliminated this problem altogether since I bought an Olympus camera.

Interesting. I was aware of cameras that stack and produce in-camera JPEGs, but I wasn't aware of some that would simply create the stack and leave it to the photographer to do the stacking.

For static images like Richard's, there is no need to buy a new camera to have this functionality. The company that produces Helicon stacking software sells software called Helicon Remote that does this for you, if you shoot tethered. I used it a few times, but I was so used to focusing with the lens barrel that I never got in the habit of using it. It's on my list to dig it out again and experiment with it more. My recollection is that when I tried it several years ago with a different body, the default values didn't work well, but a bit of trial and error allowed me to find new settings that did.

[xpatUSA]

I have eliminated this problem altogether since I bought an Olympus camera. It has the ability to do in-camera focus stacking.

I bought a Panasonic DC-G9 recently which can do 'focus bracketing'. Haven't tried it yet. The Olympus does sound gooder.

[xpatUSA]

I bought a Panasonic DC-G9 recently which can do 'focus bracketing'. Haven't tried it yet. The Olympus does sound gooder.

A couple of good articles here:

https://www.mindat.org/article.php/2...g+a+Macro-Lens

https://www.mindat.org/article.php/3...cus+Bracketing
.