Dwiggy Loc: Dunedin, FL

Hey I'm just an amateur at this thing, but what is Focus stacking? Thanks for your help.

Quixdraw Loc: x

Desert Gecko Loc: desert southwest, USA

Focus stacking is a technique where you take two or more shots of the same exact scene, without moving the camera, while focusing on different areas -- then merging the photos together, keeping the in-focus parts of each one so you end up with a single photo that's in focus from corner to corner.

For example, I might mount my camera on a tripod and frame a scene of a pasture full of wildflowers. I want to capture flowers in the very near foreground at my feet but I also want to capture the ones out in the field, and also the distant mountains and dramatic sky (this was a real scenario for me recently). I could stop down my lens to its max of f/22 to get a broad depth of field (in-focus range), but it probably wouldn't be broad enough to get everything with the lens I'm using, plus stopping down like this cause diffraction and reduces sharpness. So instead I focus stack.

I use auto settings to set exposure, then I switch to full manual so nothing changes except focus (I want same aperture and same exposure) and I focus on the near-ground. I'm shooting at a middle aperture of around f/8, so I know that my image will be very sharp and in focus for about half the image, but I only need the near third or so, but it's nice to have a bit of overlap. For my second image I keep all settings and camera position identical and change only focus, which I get on the distant pasture in about the middle of my image. For the third frame I focus near the distant mountains, just shy, knowing that everything from that point and beyond will be in focus at f/8, plus quite a bit in front of that point, so I'll have overlap with the middle image.

I use focus peaking sometimes to know for sure what's in focus, but I've done so much of this I usually don't bother with it for routine scenes like this. For macro photography, I would use it and I would have a lot more frames to stack. How many frames with different focus points you shoot depends on how much of a each frame will be in focus, and this depends on your gear and your settings. I usually need two but I take three to be safe.

For processing I use Photoshop. The process is automated, but I still watch it closely because Ps does mess up sometimes, but if you have a good overlap of in-focus areas it usually gets it right. Explaining the process is beyond the scope of this answer. In a nutshell, Ps takes the images as layers and aligns them then looks for the areas that are in focus. It keeps these areas of each image and stacks the images together while discarding the out-of-focus parts so you end up with a single image that's all in focus. There are a few options and settings to choose, all explained in any of countless video tutorials on YouTube that can walk you through it. The entire process is quite easy really.

rmalarz Loc: Tempe, Arizona

As Desert Gecko wrote. You can see some really incredible work done with stacking here on UHH. Just look for photos posted by sippyjug104.
--Bob

Dwiggy Loc: Dunedin, FL

Thanks! I'll check it out.

Dwiggy Loc: Dunedin, FL

Thank you for the great explanation. I do think looking at some YouTubes will help walk me through it. Appreciate the help.

Dwiggy Loc: Dunedin, FL

Yes, I've seen comments on some UHH's photos and wondered what it referred to. Thanks.

Cany143 Loc: SE Utah

What Desert Gecko said. (Good job, Gecko....)

I'll only add that a key step of the process (during processing) can often be, as Gecko rightly states, "....usually gets it right.... Explaining the process is beyond the scope...." may indeed need explanation. The difficulty in doing so, however, is tricky because rather than there being a single method or tool or technique that may need to be used (while 'preparing' any of the separate layers before blending), there are many. And demonstrating any of those in words is difficult at best. As with most things, though, once you've focus stacked enough diverse types of images enough times, you get a sense for which of the methods will work best, and those become simple and quick.

Dwiggy Loc: Dunedin, FL

Thanks for the further explanation...helpful.

Desert Gecko Loc: desert southwest, USA

Thanks for not tearing apart my reply, which was pretty simplistic and specific. I offered an example of how I typically shoot a stack of a landscape scene. There are of course other ways to stack for different purposes.

Another example is getting multiple subjects in focus with an out-of-focus background. Using my wildflowers scene again, let's say I wanted to get a relatively close shot of some of the flowers but with only the blooms in focus and not the stalks and ground. I wouldn't be able to do that with one shot because to get all the blooms in focus, the background stalks and ground would also be in focus. So I could use a large aperture for a very narrow depth of field and focus on the closest blooms for the first shot. Anything farther away than the closest blooms will be out of focus. Next, I focus on a bloom or blooms a little farther away, so the closest ones and everything else will be out of focus. I repeat this focusing progressively farther away, always getting only the blooms in focus.

When I stack all these in Photoshop, it should merge the photos into one with all the blooms in focus but the stems and background out of focus. But this sort of scenario is one where Photoshop tends to work too well. It's likely that I will have inadvertently captured some background or stems or something in focus in one of the shots, and Photoshop will notice it. This is a time when I would correct Photoshop by going into the layer with the unwanted in-focus area and painting it out to hide that part of that shot and allow the out-of-focus part of another photo to fill in. This is easy to do, and even if you don't really understand layers and masking, a good tutorial will walk you through it.

This is similar for macros and even for something like an automobile when you want everything around the car out of focus.

jerryc41 Loc: Catskill Mts of NY

This is probably more info than you want, but here it is. : )

https://www.youtube.com/watch?v=F3Dz34MMjQ0&t=142s
https://northrup.photo/my-account/download-sdp-ebook/stunning-digital-photography-video-index/landscape-focus-stacking/
https://digital-photography-school.com/post-processing-focus-stacked-images/
https://digital-photography-school.com/photograph-images-needed-focus-stacking/
http://www.earthboundlight.com/phototips/focus-stacking-software-photoshop-helicon-combinezp-zerene.html
http://www.lightstalking.com/focus-stacking-in-photoshop/
http://zerenesystems.com/cms/stacker/docs/purchasing
http://www.heliconsoft.com/heliconsoft-products/helicon-focus/
http://www.picturecorrect.com/tips/simple-steps-for-focus-stacking-in-photoshop/
http://digital-photography-school.com/how-to-improve-your-long-exposure-with-photo-stacking/

Guyserman Loc: Benton, AR

This is important. None of the out-of-focus area is discarded. It is simply masked out. You can still edit the individual layers any way you desire.

Mark Sturtevant Loc: Grand Blanc, MI

Sippyjug does super close up focus stacks that are near microscopic. But focus stacking can be done with any macro lens on larger subjects, or even with ordinary lenses on landscapes where you focus on near objects, and then on objects farther and farther away. There are a variety of ways to incrementally change focus. But that's a long-ish story.

alphadog

Thanks for this... have never used it either, the "short" version is long enough to scare me further ... but thanks for the information

Sidwalkastronomy Loc: New Jersey Shore

I have a nice macro lens and ring light from my dental office so I'll have to try it sounds interesting. I'll have to see if my photoshop elements 20 does that.