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Focus Stacking
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Jan 23, 2018 09:23:55   #
Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga
 
The major drawback to stacking is that it requires lots of computer resources.

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Jan 23, 2018 09:27:12   #
jcboy3
 
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.

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Jan 23, 2018 09:28:48   #
LoneRangeFinder Loc: Left field
 
peterg wrote:
Perhaps. But if moving the camera didn't work, people wouldn't be using focusing rails. Example: "StackShot" by Cognisys, http://www.cognisys-inc.com/products/stackshot/stackshot.php .


Zerene, which makes software for stacking, has a table for best results based on magnification. The table specified whether focusing with the lens or using a rail is preferred. There is also a great deal of information on stacking in the UHH true macro section. Results vary with the software used—the quoted poster may have been using inferior software or made errors in the collection of files to stack. Zerene is very good at processing stacked images. I’ve tried 5 different ones and Helicon Focus is second—but Zerene is better.

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Jan 23, 2018 10:00:02   #
kdogg Loc: Gallipolis Ferry WV
 
Check out this site. https://digital-photography-school.com/photograph-images-needed-focus-stacking/

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Jan 23, 2018 11:18:03   #
cbtsam Loc: Monkton, MD
 
cactuspic wrote:
Both methods will work; but, depending on the magnification, one will work better. For magnifications of 1:1 or less, turning the focus ring tends to work better. For magnifications greater than 1:1, a rail works better. If you go to the Zerene Stacker website, there is a tutorial on this very topic by the author of Zerene.

In addition to the true macro forum, the website photomacrography.net is a wealth of info. Enjoy stacking although it can become addictive.


Thanks for your help, cactuspic. It's a nice summary statement. However, the Zerene site [https://zerenesystems.com/cms/stacker/docs/troubleshooting/ringversusrail] suggests using the rail mainly rather closer than 1:1.

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Jan 23, 2018 11:56:08   #
speters Loc: Grangeville/Idaho
 
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)

Moving the camera (preferably with a bellows) is way more precise ( if one wants to get into really strong magnification)! Increments of 0,00+mm can easily be achieved, which is not possible by adjusting the focus ring on a lens. And there are many companies out there that have devices (bellows & software) that will do the task automatically for you !

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Jan 23, 2018 12:09:48   #
PHRubin Loc: Nashville TN USA
 
Rongnongno wrote:
I can address only this part...

If you move the camera forward or backward the perspective changes with the focusing plane. I would not do that.

Now if the camera is moved side ways on the same focus plan this would create a stitch-able panorama. This type of motion is used for reproducing large documents (or not so large depending on the intent) or parallel (walking) panoramas. Be aware of parallax errors when doing this.

This may not be the answer you seek.

As to the D850... It is not able to move itself so... Only the first type, moving the focus plane is available.
I can address only this part... br br If you move... (show quote)


Not only does perspective change, but some software might need identical perspectives to be able to stitch them together.

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Jan 23, 2018 12:10:30   #
cbtsam Loc: Monkton, MD
 
kdogg wrote:
Check out this site. https://digital-photography-school.com/photograph-images-needed-focus-stacking/


Thanks, kdogg, but this site seems to apply only to Canon cameras.

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Jan 23, 2018 12:35:33   #
cbtsam Loc: Monkton, MD
 
jcboy3 wrote:
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.


Thanks for your input, jcboy3; the focus puller idea looks like a great idea, and there seem to be decent examples for about $17.00 (FocusShifter LensShifter, red).

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Jan 23, 2018 12:38:14   #
cbtsam Loc: Monkton, MD
 
Gene51 wrote:
The preferred method is to move the camera for stacking, if doing macro. Of course this is predicated on the ability of the amount of movement fore/aft is able to be handled by the rail you are using. By this I mean if your subject is 5 inches in depth and you are using a rail that only has 4 inches of total movement, you are not going to get the result you are looking for.

The reason it is preferred to focusing is exactly what you describe - the change in focal length and the corresponding change in field of view as you focus closer to 1:1. Nikkor lenses are not as bad as some third party lenses. Moving the camera/lens addresses this as long as the rail is long enough.

The change in perspective at macro distances is not an issue since only the subject is in focus and the background is of no real concern. The greater concern is the increase in depth of field when you focus adjust. When you distance-adjust the DoF is constant, you are just moving it.

In the beginning I used to use a DoF app on my phone, and determined the DoF for my focus distance and aperture. I would cut the distance in half for more accurate focus. So if the calculator said at F11 at a given distance I would have 1 in DoF, I would use .5 in. I would use a rail and advance the focus 3/8" to ensure no gaps. What I do now is just "wing it" with focus adjusting, making sure I use very tiny increments on the focus ring. Any perspective/magnification/angle of view issues are typically handled well by software. If your lens is a heavy breather, make sure that you use a looser composition, since much of the border of your image will be unusable.

It is better to have more shots and overlap your focus as much as possible, to avoid gaps in focus, regardless of whether you focus-adjust or distance adjust to create your stack sequence.

When doing stacking for more distant subjects, like architectural and landscape, there is only one real option - to change focus, but "breathing" is not an issue at those distances.

Hope this provides some clarity.

.
The preferred method is to move the camera for sta... (show quote)


Thanks, Gene51, for your typically clear and useful input. Much appreciated.

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Jan 23, 2018 12:54:00   #
Festus Loc: North Dakota
 
LoneRangeFinder wrote:
As Screaming Scott posted: you posted in the “wrong” forum.

Here’s some information on image size: https://zerenesystems.com/cms/stacker/docs/faqlist#does_zerene_stacker_correct_for_changes_in_magnification_as_i_focus

FWIW: Zerene is a software dedicated to focus stacking—and is still the best available.

The two methods are dependent on magnification: With macro, I would recommend a focusing rail; for landscapes, your only option is the focusing ring


If you are going to spend $ for Zerene Stacker, please do some research on Helicon Focus and compare the 2. Many prefer Helicon, ease of use, more intuitive than Zerene, and possibly more features. Just saying, Zerene not necessarily the "best available".

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Jan 23, 2018 13:28:34   #
cactuspic Loc: Dallas, TX
 
cbtsam wrote:
Thanks for your help, cactuspic. It's a nice summary statement. However, the Zerene site [https://zerenesystems.com/cms/stacker/docs/troubleshooting/ringversusrail] suggests using the rail mainly rather closer than 1:1.


You are right about the chart. It does recommend using the ring with a raisin, I suspect with a cropped sensor (less magnification needed to fill the frame of a cropped sensor than to have a raisin fill a full frame sensor.). It has also been my experience that stacking with a macro and tubes works well with the focus ring (or software that controls the focus ring).

Experiment and try it both ways. I think you will find that stacking using your macro lens will be better moving the focus ring rather than the camera, because the perspective changes more with moving the camera than that caused by focus breathing as shown in the Zerene tutorial. The one trick with turning the ring is making sure your increments are small enough. I have not tried your lens. If you have problems, there is software that you can use to control the camera, iPhone apps to control the camera, and external devices such as the CamRanger that control the camera. Focus pulling sounds interesting, but I have not tried it. Higher magnification requires a different approach. Enjoy. After several thousand stacks, I have to repeat, it can be addictive.

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Jan 23, 2018 16:42:59   #
frankraney Loc: Clovis, Ca.
 
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)


Number I is the correct way of doing this. The composition and distance to subject does not change. Both of these would change in II, and each photo would be different, and as you get closer the photo would be bigger, and as you backed up it would be smaller...You may be able to accomplish the stacking but it would take a long long time cropping and aligning. In number I each photo would be identical in comp and only the focus point changes slightly.

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Jan 24, 2018 00:58:14   #
Vienna74 Loc: Bountiful, Utah now Panama
 
I have the same lens, probably an older version, I think ca. 1981. This is a focus stacking shot of a geranium I took last August. It was 7 photos stacked in PS, and I have stacked over 20 photos a couple of times. Just go try it! You will answer all your questions by doing it.
.


(Download)

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Jan 24, 2018 04:28:24   #
Richards' Small World
 
I have been into Macro photography for over 50 years. After all of my research I settled on the following hardware and software that has worked well for me.

1. Stack Shot rail system
2. Helicon remote
3. Helicon Focus
4. Gear Head
5. Slider.

I started my Stack shooting with a Nikon D600 and a 60mm Micro, and updated my 60mm, and bought a 105mm.

This has worked for me and a lot of shots have been taken and a lot of experimentation to get where I am right now. The issues you have with rear focus I found to be almost completely corrected by making sure you camera is parallel and square with your subject.

DOF calculator is a big help in Helicon Remote. Always overlap so your photos come out in focus. 99.9 %of my photos do not need any further edits. I try to keep my movement of the camera to 10mm or less between shots. Less if I am at 1 to 1 magnification.

To answer your question on number of shoots depends on the size and area you want to photograph. My normal shots range from 50 to over 100. I always shoot RAW.

To answer your question about camera stationary and let the lens move I haven't had much luck with. One of the main reasons is if your lens is set to full Macro the barrel can't not move. So rail shooting is the way to go.

I am sure you have run into the issue that you must keep everything still while shooting stack shots. I invested in a surface plate which is a 2' x 3' 3" thick piece of granite on a metal frame plus Helicon remote allows me to program the camera to hold and not shoot until all vibrations stop.

One of my biggest issues has been that all of my photos come out somewhat soft which I thought was a cause of the sensor filter on the D600. So I have had to sharpen all of my photos. I just upgraded to the D850 expecting to get razor sharp shots but still have to sharpen after the stacking is complete. I think the softness is a fault of the stack and not the camera. Anyway I have only had the 850 for 3 weeks and I am experimenting as it is a whole lot different from my 600.

I hope this is a help to you, and gives you some things to think about.

Richard

PS:

If you would like to see my work my website is:

richardssmallworldphotography.com

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