Focus Stacking Question

[Greg Haag]

I have not done any focus stacking, but I am try to learn. My first results of blending the image was a big failure. I am uncertain if it was my technique or my processing method. It was a blend of 44 images, focus was manual, shot on tripod w cable release. XF IQ4 150 w 150mm w extension tube tethered to computer into C1. I processed the images to JPEG's then imported into Photoshop as layers, auto aligned layer then auto blend layers. The results were not good. Can anyone tell me where I went wrong?
Thanks in advance!
Greg

 

[rdeloe]

Unfortunately you've discovered one of the limitations of focus stacking. I use Helicon Focus, which is excellent and automates the process. However, the unsightly edges you're seeing still appear when there aren't enough images in the stack to provide sharply-focused information in those zones.

If you look at the images for that area you'll see that in none of them is the transition zone between the metal piece and the hammer's handle sharp. To avoid this, try a larger aperture (to get more of each image in the stack in critical focus) and more images in the stack.

Another way to avoid this is to use tilt to locate the plane of focus so that all elements of the image you want critically sharp are. Sometimes tilt isn't enough in these table-top scenes, so I combine tilt with focus stacking; many fewer images are needed in the stack compared to shooting without tilt.

 

[gerald.d]

Nothing you do with regards to shooting technique will fix this.

Wherever you have a gap between foreground and background, you will have this problem. Exactly how much of a problem it is will vary for every single image depending on the exact layout of the subject matter.

The reason why you are seeing this is - once it has been explained - obvious, and you will immediately appreciate there is no solution. And it is this.

When a subject is out of focus, it is larger than the subject when it is in focus. Thus, if you are focusing on a layer that is beneath an object above that layer, the object above is out of focus, and obscures the very area you are focusing on.

The only way to solve this for subject matter similar to what you are sharing here is by retouching in post.

Kind regards,


Gerald.

 

[gerald.d]

Unfortunately you've discovered one of the limitations of focus stacking. I use Helicon Focus, which is excellent and automates the process. However, the unsightly edges you're seeing still appear when there aren't enough images in the stack to provide sharply-focused information in those zones.

If you look at the images for that area you'll see that in none of them is the transition zone between the metal piece and the hammer's handle sharp. To avoid this, try a larger aperture (to get more of each image in the stack in critical focus) and more images in the stack.

Another way to avoid this is to use tilt to locate the plane of focus so that all elements of the image you want critically sharp are. Sometimes tilt isn't enough in these table-top scenes, so I combine tilt with focus stacking; many fewer images are needed in the stack compared to shooting without tilt.

With respect, this is not correct.

It doesn't matter how many images are in the stack. There will always be a blur around the foreground objects. It is literally impossible to render the background object or surface where it is adjacent to the foreground object - the out of focus foreground obscures it.

Yes, you can mitigate to a certain degree by stopping down the lens, but then you start to hit a whole bunch of other issues.

No lens movements would solve the problem seen here.

Kind regards,


Gerald.

 

[Paul2660]

I would still try Helicon, and see if can't get a better blend. As it should still get a better fit. The tools appear to be in focus, the back ground out of focus, thus Helicon should be able to handle this and leave the background out of focus. At least it's worth a try, The software has really never failed for me, but I am usually working for an entire image in focus, not a selective focus. Helicon works well in that regard.

Paul C

 

[gerald.d]

I would still try Helicon, and see if can't get a better blend. As it should still get a better fit. The tools appear to be in focus, the back ground out of focus, thus Helicon should be able to handle this and leave the background out of focus. At least it's worth a try, The software has really never failed for me, but I am usually working for an entire image in focus, not a selective focus. Helicon works well in that regard.

Paul C

It is physically impossible to fix this. Doesn't matter which parameters or methods you use in either Helicon or Zerene.

The reason it is physically impossible to fix this is because it is physically impossible to capture the background in focus where there is a Z-axis differential between foreground and background.

It's relatively simple to test this without even getting involved in stacking.

Just try to take an in focus image of the background adjacent to the foreground where there is an actual gap between the two. Can't be done.

Kind regards,

Gerald.

/edit

Even if you are not concerned about the background being in focus, you still have the same problem. When the background is "a little bit out of focus" , the foreground will be "more out of focus" , and hence still optically block the less out of focus background, resulting in the exact same problem.

Until the focus stacking software has some kind of AI to spot where this occurs, and uses a smart content aware replace algorithm to fill in the gaps that the camera is not capable of resolving optically, the only solution is retouching.

 

[vjbelle]

I have to agree with Gerald in that there are some images that cannot be stacked successfully. However I have found that when I encounter this I have been able to mitigate fairly well by using the tools inside of either Helicon or Zerene. Both of those programs offer retouching that is very powerful and easy to use. That workspace can be saved in either program in case you have to revisit for a little more retouching. Experience is the key......

Victor B.

 

[Greg Haag]

I have to agree with Gerald in that there are some images that cannot be stacked successfully. However I have found that when I encounter this I have been able to mitigate fairly well by using the tools inside of either Helicon or Zerene. Both of those programs offer retouching that is very powerful and easy to use. That workspace can be saved in either program in case you have to revisit for a little more retouching. Experience is the key......

Victor B.

I can only imagine how accurate and important this statement is "Experience is the key......"

 

[vjbelle]

I use stacking mostly for 'expanding' the area of focus I want instead of stopping down. This is especially useful, for me, when I am shooting landscapes that don't require everything to be in focus but instead an important area within the image. It usually only takes three or four images but it makes a really big difference.

Victor B.

 

[rdeloe]

"Avoid" clearly wasn't a good word choice. Yes, physics -- we can't "avoid" physics.

However, I mitigate the problem of edges all the time using more images in the stack shot straight-on (which can cut down retouching in some but not all cases), with tilt, and with stacks made of tilted images. These approaches cannot negate physics, but they can help a lot.

Regarding retouching, I've found that if Helicon can't fix the problem on its own, retouching inside Helicon by brushing from different layers in the stack doesn't help because there simply isn't better information to brush in from another layer. Retouching in Photoshop or Lightroom is what has worked for me; in this case, "retouching" means "cloning".

 

[Greg Haag]

Paul, I took your advice and reprocessed the image in Helicon and the results are still not right but it was far superior, at least in this instance, to photoshops version. I guess next I need to understand the nuances in Helicon that Victor described, as well as, possible refinement in Photoshop that Gerald and Rob described. Thank you to everyone for sharing your insights on this. I will keep working at it.
Thanks again,
Greg

 

[gerald.d]

"Avoid" clearly wasn't a good word choice. Yes, physics -- we can't "avoid" physics.

However, I mitigate the problem of edges all the time using more images in the stack shot straight-on (which can cut down retouching in some but not all cases), with tilt, and with stacks made of tilted images. These approaches cannot negate physics, but they can help a lot.

Regarding retouching, I've found that if Helicon can't fix the problem on its own, retouching inside Helicon by brushing from different layers in the stack doesn't help because there simply isn't better information to brush in from another layer. Retouching in Photoshop or Lightroom is what has worked for me; in this case, "retouching" means "cloning".

Shooting more images doesn't mitigate anything. For any focus stack, the number of images you need to shoot is determined by just two things. The depth of focus of a single image, and the depth of focus you want in the final file.

There are of course instances where tilt can help, but I come back to the example shown.

No lens movements held through the stack will solve the fundamental physics problem here. The arrangement of the objects in the frame require multiple lens movements in different parts of the frame in order to get foreground and background focused simultaneously.

And without movements, it makes no difference whether you shoot 40 or 400 images for this set up, the results will be the same.

You can mitigate by stopping down to close the foreground/background gap so that it is covered by the depth of field obtained by a smaller physical aperture, but as mentioned previously, that typically introduces other challenges.

Regards,

Gerald.

 

[Mexecutioner]

Also you can give Zerene Stacker a try. In my experience both Helicon and Zerene treat the files differently and depending on the case the reults are better on one of the other. I have used Zerene to stack 100+ or so frames (from a lower res camera) and the results were very good and had fewer areas that needed retouching when compared to Helicon, YMMV. As Rob pointed out, you most likely need to significantly increase the number of frames capture to have better transitions and defined edges, which will definitely put some stress on your computer is using the IQ4150 files. It would save time and render better results to have more shots on the stack than to try to do it with the minimum amount as you will spend more time trying to fix it.

I'd suggest you shoot a new stack with several more frames and then process them in Helicon and Zerene using the different options each software offers and see which one does a better job. Seems you own Helicon already, Zerene has a 30 day demo. Compared to these two, Photoshop does a subpar job at stacking so I never bother using it for that.

 

[vjbelle]

Definitely agree..... Zerene and Heicon can treat some stacks differently and if you are really serious about stacking it's best to own both. I've had stacks fail with one or the other and had success when switching to the other staking program.

Victor B.

 

[Greg Haag]

Also you can give Zerene Stacker a try. In my experience both Helicon and Zerene treat the files differently and depending on the case the reults are better on one of the other. I have used Zerene to stack 100+ or so frames (from a lower res camera) and the results were very good and had fewer areas that needed retouching when compared to Helicon, YMMV. As Rob pointed out, you most likely need to significantly increase the number of frames capture to have better transitions and defined edges, which will definitely put some stress on your computer is using the IQ4150 files. It would save time and render better results to have more shots on the stack than to try to do it with the minimum amount as you will spend more time trying to fix it.

I'd suggest you shoot a new stack with several more frames and then process them in Helicon and Zerene using the different options each software offers and see which one does a better job. Seems you own Helicon already, Zerene has a 30 day demo. Compared to these two, Photoshop does a subpar job at stacking so I never bother using it for that.

Thank you for sharing your insights Rodrigo, I will reshoot and give both Helicon and Zerene at try!

Victor, thank you for seconding it!

 

[rdeloe]

Shooting more images doesn't mitigate anything. For any focus stack, the number of images you need to shoot is determined by just two things. The depth of focus of a single image, and the depth of focus you want in the final file.

There are of course instances where tilt can help, but I come back to the example shown.

No lens movements held through the stack will solve the fundamental physics problem here. The arrangement of the objects in the frame require multiple lens movements in different parts of the frame in order to get foreground and background focused simultaneously.

And without movements, it makes no difference whether you shoot 40 or 400 images for this set up, the results will be the same.

You can mitigate by stopping down to close the foreground/background gap so that it is covered by the depth of field obtained by a smaller physical aperture, but as mentioned previously, that typically introduces other challenges.

Regards,

Gerald.

It's a good day when you learn something new (even if that means you were wrong).

I have a habit of not simply believing what people on the Internet say, so I had to see for myself. My kitchen counter and some kitchen tools stood in for Greg's lovely workbench and old tools. The left-hand image was made by shooting 29 stacked images, with the plane of focus aligned with the red spatula. The right-hand image is 29 images shot straight on. There's absolutely no difference after stacking.

Well damn, as they say. Somewhere along the way I picked up a wrong idea and ran with it until this very day. Thanks for the learning Gerald.

 

[4*Paul]

Agree with everything said above about using Helicon & Zerene. I generally prefer Zerene and find the (always necessary) retouching easier.
Have you tried the XF’s Focus Stacking feature? It won’t solve the problems you’ve described in this thread but makes life a lot easier by taking the guesswork out of the number of shots necessary for any particular combination of aperture and range of sharp focus required.
I’ve found (with XF + IQ3100) that it works rather well and, with ES, will quickly take all the necessary frames with uncanny silence. Just make sure that the Auto Preview setting is off because that slows it down considerably.
Tutorial link below.

 

[Greg Haag]

Agree with everything said above about using Helicon & Zerene. I generally prefer Zerene and find the (always necessary) retouching easier.
Have you tried the XF’s Focus Stacking feature? It won’t solve the problems you’ve described in this thread but makes life a lot easier by taking the guesswork out of the number of shots necessary for any particular combination of aperture and range of sharp focus required.
I’ve found (with XF + IQ3100) that it works rather well and, with ES, will quickly take all the necessary frames with uncanny silence. Just make sure that the Auto Preview setting is off because that slows it down considerably.
Tutorial link below.

Paul,
Thanks for mentioning it! I have tried the focus stacking on my 32mm and it seems great, although I still felt I struggled a bit getting it set up. On the image above, I was using a non-blue ring with extension tube and I could not get it to make any adjustments. I am not sure if that combination does not work or if I was the problem. It certainly would be my preferred way to shoot this.
Thanks,
Greg

 

[Greg Haag]

It's a good day when you learn something new (even if that means you were wrong).

I have a habit of not simply believing what people on the Internet say, so I had to see for myself. My kitchen counter and some kitchen tools stood in for Greg's lovely workbench and old tools. The left-hand image was made by shooting 29 stacked images, with the plane of focus aligned with the red spatula. The right-hand image is 29 images shot straight on. There's absolutely no difference after stacking.

Well damn, as they say. Somewhere along the way I picked up a wrong idea and ran with it until this very day. Thanks for the learning Gerald.


View attachment 179141View attachment 179142

Thanks for posting Rob!

 

[4*Paul]

On the image above, I was using a non-blue ring with extension tube and I could not get it to make any adjustments. I am not sure if that combination does not work or if I was the problem. It certainly would be my preferred way to shoot this.

Ah, I had forgotten that it doesn’t work with all lenses.
I only use a non-BR SK 120mm Macro which covers all my needs and is a (relatively) inexpensive lens.
Best of luck Greg and enjoy the learning process - which never ends!