Focus Stacking - multiple aperture settings

[EricBowles]

I led a webinar a couple of weeks ago with Nikon Ambassador Vincent Versace. One of the topics we discussed was focus stacking. He is directly connected to the development team for Nikon cameras and software, and in earlier days had talked about combining images into focus stacks.

Vincent suggested that one of the techniques he uses for focus stacking is to have a wide open set of images for the back of the in focus area so the background is nicely blurred. He might use f/8 for most of the stack, but use f/1.8 for the back of the stack.

I'd never really thought about this technique, but it makes a lot of sense. There is nothing that says a stack of images needs to have the same aperture for all images.

 

[gbodave]

Isn't that the same as not stacking but with a single image manipulating depth of field to achieve sharpness at the front and blurring at the back.

 

[kimball]

Any examples one can link to? I think I can visualize what you're talking about but just want to confirm. Sounds like one could create an image with a relatively deep DOF for the desired range that then immediately falls off -- faster than naturally possible -- to extreme out of focus at a chosen distance. This could be a very creative technique!

 

[EricBowles]

Isn't that the same as not stacking but with a single image manipulating depth of field to achieve sharpness at the front and blurring at the back.

No - he's stacking as many as 100+ images to optimize fine detail across the image. There is no aperture that would accomplish the same thing as a stack. The benefit of using a wide aperture at the end of the stack is you have a lot more control of your backgrounds.

 

[EricBowles]

Any examples one can link to? I think I can visualize what you're talking about but just want to confirm. Sounds like one could create an image with a relatively deep DOF for the desired range that then immediately falls off -- faster than naturally possible -- to extreme out of focus at a chosen distance. This could be a very creative technique!

I don't have examples and have not tried it, but that's exactly the idea. He's shooting a background at f/1.8 instead of f/5.6 or f/8. It's not perfect, but it gives you control you otherwise don't have in a normal stack.

He originally was exploring a concept of selective focus. With that approach he was combining images with different parts of a scene i focus into a single image. The idea was it provided complete control over what is in focus and how much in focus it is. Even if you wanted an out of focus background element, you could choose exactly how much out of focus.

Focus stacking can automate that more, especially if you are creative and selective about the images being combined.

 

[R.Philip]

I only have limited experience with using Nikon's focus stacking, but how does he know where in the sequence the wide open aperture images should be taken. I cannot visualize how his process. I can only see this by doing at least two stack sequences at the different apertures and examining all the images to determine witch ones to stack together. Interesting concept.

 

[bleirer]

Sounds interesting. One thought is that one benefit to stacking is using the sweetest aperture for a particular lens, and a relatively open one to avoid diffraction. To get blurry background one can choose the last shot in the sequence as the one with the blurry background. But would a smaller aperture make it drop of more gradually? Haven't tried that. Even automatic stacking software let's you go back and 'paint' the image at a given point to indicate which shot is masked and which is used in that area of the image.

 

[DRwyoming]

I only have limited experience with using Nikon's focus stacking, but how does he know where in the sequence the wide open aperture images should be taken.

You'd take a single image of the wide aperture shot and then then use Nikon's Focus Shift Shooting feature to capture the rest of the stack at your desired aperture. Nikon's Focus Shift Shooting feature doesn't allow changing parameters like shutter speed or aperture during the stack sequence but it's easy enough to do it manually.

I'd never really thought about this technique, but it makes a lot of sense. There is nothing that says a stack of images needs to have the same aperture for all images.

Intereresting idea, makes sense. Thanks for posting Eric!

 

[Deleted member 115]

. . . but it's easy enough to do it manually.

Do you create a stacked image using automated software like PS then use masking for the back ground?

 

[R.Philip]

You'd take a single image of the wide aperture shot and then then use Nikon's Focus Shift Shooting feature to capture the rest of the stack at your desired aperture. Nikon's Focus Shift Shooting feature doesn't allow changing parameters like shutter speed or aperture during the stack sequence but it's easy enough to do it manually.

I thought PS, or whatever stacking software is used, looks for the areas in focus when blending the images. Or, do you manually blend the focus stack sequence with the wide open image?

 

[EricBowles]

I thought PS, or whatever stacking software is used, looks for the areas in focus when blending the images. Or, do you manually blend the focus stack sequence with the wide open image?

That's the idea. You would create a normal focus stack of the entire image. But you would also add a single image or a short series at the front and back of your set. This would give you the ability to select a shallow DOF image or images for the front and back of the stack.

You can select any images you want - in focus is what the software seeks. But with a shallow DOF, you could use an in focus image that has a very shallow DOF and an out of focus background. You also have the ability to use masking in some of the software programs.

The automated stack is an option, but not the only option. You can create a stack or additional images manually. It just requires attention to technique.

This is not a concept that just applies to macro and close up images. It can work for landscapes, street, or even some wildlife images. For example, you might use a slow exposure for the foreground images to emphasize detail in the subject, but then use a higher ISO and wider aperture to freeze motion or birds flying in the background and have them in focus.

The point is you are not limited to the settings of a single stack. You can change aperture, shutter, or ISO. You also can choose final images that are still soft and out of focus, but the degree of OOF that you desire.

 

[DRwyoming]

I thought PS, or whatever stacking software is used, looks for the areas in focus when blending the images. Or, do you manually blend the focus stack sequence with the wide open image?

Do you create a stacked image using automated software like PS then use masking for the back ground?

I certainly haven't tried it yet as I just read about this in Eric's post this morning but I suspect you'd do what Hut suggests. Run the focus stacking in dedicated software or PS to create the stacked sharp image and then bring it into PS as a layer above your wide aperture blurred background layer and then use a mask on the sharpened layer as needed. You might save some time by building a luminosity mask using channel info or one of the good third party mask building tools.

 

[Deleted member 115]

That's the idea. You would create a normal focus stack of the entire image. But you would also add a single image or a short series at the front and back of your set. This would give you the ability to select a shallow DOF image or images for the front and back of the stack.

You can select any images you want - in focus is what the software seeks. But with a shallow DOF, you could use an in focus image that has a very shallow DOF and an out of focus background. You also have the ability to use masking in some of the software programs.

The automated stack is an option, but not the only option. You can create a stack or additional images manually. It just requires attention to technique.

This is not a concept that just applies to macro and close up images. It can work for landscapes, street, or even some wildlife images. For example, you might use a slow exposure for the foreground images to emphasize detail in the subject, but then use a higher ISO and wider aperture to freeze motion or birds flying in the background and have them in focus.

The point is you are not limited to the settings of a single stack. You can change aperture, shutter, or ISO. You also can choose final images that are still soft and out of focus, but the degree of OOF that you desire.

I have just begun to explore focus stacking. This is definitely a technique I would like to learn for landscapes. Hopefully I will find time and frame of mind in the near future to dedicate

 

[DRwyoming]

This is definitely a technique I would like to learn for landscapes.

Don't rule it out for wildlife.

I visited a local owl's nest yesterday to find the parent had moved out of the nest and was roosting on a nearby branch that's a bit farther back than the nest. I stopped my 600mm f/4 + TC down to f/16 to try to hold both the chick and the adult in sharp focus but even that wasn't enough DoF, the background was beginning to sharpen up and show a lot of distractions and the ISO which was already high on this overcast day was through the roof. So I shot an image at f/6.3 focused on the chick's eye and the quickly scrolled the AF point over to the adult's eye and took a second shot.

I thought the stacking might be a painful adventure in masking but since the two didn't overlap it turned out to be dirt simple. I just stacked the two images as layers in PS, selected both ran an Edit>Auto Align Layers and then an Edit>Auto Blend Layers and then edited the top mask (the chick) a tiny bit so that branch behind its head stayed soft and wasn't sharpened up along with the adult.

Nikon Z6 II, 600mm f/4 + TC-14 iii, f/6.3, 1/250", ISO 3200

You can only see EXIF info for this image if you are logged in.

Anyway, in addition to macro and landscapes sometimes a bit of focus stacking can be useful for wildlife images.

BTW, here's the two original images:

You can only see EXIF info for this image if you are logged in.

You can only see EXIF info for this image if you are logged in.

 

[Deleted member 115]

Don't rule it out for wildlife.

I visited a local owl's nest yesterday to find the parent had moved out of the nest and was roosting on a nearby branch that's a bit farther back than the nest. I stopped my 600mm f/4 + TC down to f/16 to try to hold both the chick and the adult in sharp focus but even that wasn't enough DoF and the background was beginning to sharpen up and show a lot of distractions and the ISO which was already high on this overcast day was through the roof. So I shot an image at f/6.3 focused on the chick's eye and the quickly scrolled the AF point over to the adult's eye and took a second shot.

I thought the stacking might be a painful adventure in masking but since the two didn't overlap it turned out to be dirt simple. I just stacked the two images as layers in PS, selected both ran an Edit>Auto Align Layers and then an Edit>Auto Blend Layers and then edited the top mask (the chick) a tiny bit so that branch behind its head stayed soft and wasn't sharpened up along with the adult.

Nikon Z6 II, 600mm f/4 + TC-14 iii, f/6.3, 1/250", ISO 3200
View attachment 18986

Anyway, in addition to macro and landscapes sometimes a bit of focus stacking can be useful for wildlife images.

BTW, here's the two original images:

View attachment 18990
View attachment 18991

That’s awesome