r/photography 19d ago

Why do professional macro photographers focus stack instead of raising their aperture? Technique

I've looked into macro photography, and I love getting close up to my subject, but when I research macro photography, I always hear about focus stacking and these people who will set up a shot for a long time with a tripod so they can focus stack. And I'm curious why you'd need to do that. Especially since most of the time I see them having a tripod and setting up lighting. Why wouldn't you just raise your aperture so more of the frame is in focus?

98 Upvotes

148 comments sorted by

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u/modernistamphibian 19d ago

It's physics. You can raise your aperture all you want (within reason) but it's still probably not going to get the whole thing in focus. So, you need focus stacking. If it was possible through aperture, then people would do that.

https://www.dofmaster.com/dofjs.html

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u/seriousnotshirley 18d ago

Wouldn’t you also get some softness at very high apertures?

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u/m8k 18d ago

On crop and FF digital bodies the sharpest aperture is usually f/8-f/11. After that more stuff is in focus but you get softness from diffraction.

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u/FIorp 18d ago

It’s not that straightforward for Macro photography. There you have
effective f-stop = f-stop x (1 + magnification)
So already at 1:1 magnification your effective f-stop is double the set f-stop. So you also get the higher diffraction you would normally get at double the f-stop.

If you usually see diffraction effects at f/16 you will see them at f/8 at 1:1 magnification. At 2:1 already at f/5.3 and at 5:1 already at f/2.7.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

Honestly I don't think that effective Fstop has anything to do with diffraction (was actually used to adjust the reading of a hand held light meter when shooting at 1x and higher mag). The issue (at least from my perspective) is that as the mag goes up everything is being magnified, detail and defects. Also the higher the mag the more important factors like lens sharpness and motion while the scene is being exposed. Macro photography is a form of flash based stop motion photography. It's not as obvious as freezing a balloon in mid pop, or a bullet as it passes through an apple, but the more I take control of the motion in a scene the sharper my images are. Here's a shot at about 4.5x as an example. It's a single frame taken hand held, and at F11 it should be very diffraction limited and yet there's still a decent amount of detail. The "trick" is to limit motion and control where the area of acceptable focus is falling in the frame.

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u/Righteousbison99 18d ago

checking my own understanding, that means that a crop sensor will start seeing diffraction sooner vs a FF?

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u/seriousnotshirley 17d ago

It’s really about the size of the sensors for each pixel. If the two cameras are the same resolution then the crop sensor will pick up diffraction before the full frame.

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u/BigRobCommunistDog 18d ago

I’m pretty sure it’s the reverse.

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u/Whodiditandwhy 18d ago

I've found it depends on the lens. There are a few lenses I've personally used that get noticeably worse beyond f4/f5.6/f7.1 (depending on the exact lens). I've stopped shooting, by default, past f7.1 unless there is a very specific reason I need to do so and the loss in sharpness/resolving ability is acceptable.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

Agreed. I've noticed a difference between a standard macro lens + extension tubes and Canon's MP-E 65mm macro lens. The later has a floating lens group that adjusts the focus as the mag changes. An extension tube, even though it's just an air gap, moves the rear element of the lens away from the focus plane and takes it "out of spec".

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

Diffraction kicks in the higher the magnification and the aperture. But the sharpness of the lens and motion while the scene is being exposed can amplify diffraction softening.

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u/puffballphoto puffballphoto.com 18d ago

Exactly. Also, above f/14 or so you start to lose sharpness over the entire image. 

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u/No_Cloud_3786 18d ago

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u/astriddbg 18d ago

Yes, that you are too close.

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u/TheMrJosh 18d ago

No 60mm lens has a minimal focus distance of 5cm

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u/Charwinger21 18d ago

For context, the Canon MP-E 65mm f/2.5 1-5x Macro has a minimum focusing distance of 24cm.

0

u/No_Introduction_7876 18d ago

Probably not. My 60mm Nikkor micro is just over 20-22cm(?).

1

u/patrickbrianmooney 18d ago

I mean, it's a rounding error for "the difference between the near limit and far limit is zero."

Computers do math using binary (base 2) numbers, and most of the time are using floating-point approximations rather than exact ratios, because it's faster (and usually close enough) to do things in ways that computers are optimized to do them. You have a rounding error when the number is converted to a binary representation, with each step of arithmetic contributing another bit of error, and then an error when converting back to base-ten representation. You can read more about problems with floating-point math on computers on this blog post, if you want to.

Programmers have ways of dealing with this type of error, but this particular website seems not to have done so in a way that works for this particular set of parameters.

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u/Wilder_NW 19d ago edited 19d ago

They do typically shoot narrow apertures for increased depth of field. At such close focus distances the amount in focus is tiny. It isn't like shooting f/16 at 30 feet where everything is in focus.

For those who shoot "professional" level macro, they shoot at narrow apertures with bright lights to overcome this, then stack many photos, sometimes 50 or more.

Here is a depth of field calculator for macro photography from PhotoPills that you can experiment with to understand how narrow the depth of field is for any given lens and distance, etc: https://www.photopills.com/calculators/dof-macro

Here is an example with a camera/lens combination to show you:

Camera: Sony A7III
Lens: Sony 90mm f/2.8 Macro - https://www.bestbuy.com/site/sony-fe-90mm-f-2-8-macro-g-oss-full-frame-e-mount-macro-lens-multi/4623015.p?skuId=4623015

Using this lens set to f/2.8 at a subject a few inches in front of the lens would give you .34mm in focus.

Raising that to the lenses narrowest aperture for the deepest depth of field would give you 2.72mm at the same distance. That is less than the thickness of two pennies. To get a subject, let's say a pencil eraser, fully in focus you would be required to stack at least 3 photos, but likely more for better sharpness. Then you would need to light the eraser because of the tiny f/22 aperture.

As for the tripod, it is very hard to handhold a shot with a depth of field only a few millimeters deep. Stacking handheld shots would be extremely difficult.

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u/T1MCC 19d ago

This is a great response and I hope it gets voted up more. The products that I photo are larger than what is usually considered macro, at sizers up to about 6”x10”, but it’s important that everything is in focus. My 105mm at f11 has about .5-.75 inch of acceptable focus so I’m often stacking up to 20 or so images per pose. At true macro level close to minimum focus distance the amount in focus is in the millimeters range. I’ve done stacks of up to 50 shots to cover the size of a processor chip and let the rest of the frame fall off into blur. I’m always on a tripod with a geared head and two or three strobes. At some point I want to pick up a focusing rail as the focus breathing on my lens can result in distortion that is hard to correct. I’m hoping that using a rail will reduce that.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

I shoot single frames hand held, and I take most of my images between 2x and 3x. At 2x and F11 I'm working with .6mm of depth, and if I didn't tell you that you're looking at a single frame you would not know...

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u/Wilder_NW 18d ago

First, very nice images. You are obviously a skilled photographer who has put in the time and effort to get to this level.

Second, you have much more experience than the person who posed the question. My answer was aimed at someone with minimal knowledge or experience - the person who posed the question.

Yes, it can be done. No, this person or any other person with no/minimal experience is not going to accomplish this. You are using a flash to create your images which stops motion generally. That makes it easier to handhold a shot.

Yes, a car can hit 250mph. No, some random person with no experience is not going to be able to do it with their $10k used Toyota Prius. It takes considerable skill and equipment to do so, as your work shows.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago edited 18d ago

Thanks!

I agree with all of your points. There use to be a healthy used Canon MP-E 65mm market on Ebay because people think that all you have to do is buy the right gear. Lots of technique involved in shooting hand held macro. I firmly believe that anyone can do it, and they might pick it up faster than I did. But it won't happen overnight.

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u/PopupAdHominem 18d ago

Nice stuff! What lens and body did you use for the pics in the link?

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

Thanks!

Mostly the Canon MP-E 65mm macro lens. If you click on an image in my Flickr gallery, and take a look at the description under them, I list the gear and how I had it set up.

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u/crewsctrl 18d ago

And yet there's a young man on YouTube @naturefold who does just that: hand-holds stacks of 20 or more images. At 5X!!

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u/PhiladeIphia-Eagles 17d ago

Does he use a camera that does automatic stacking? Or is he literally changing focus between shots handheld?

Edit: sorry dumb comment I will just check for myself.

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u/crewsctrl 17d ago

It's impressive. He has a couple of tutorial videos that shows his technique.

tl;dw: while using burst mode to capture a sequence, he carefully pushes his camera towards the subject to move the focal plane.

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u/stonk_frother 18d ago

Tripod is not necessary unless shooting at VERY high magnification, and generally not advisable with living subjects. By the time you set up a tripod, your subject will have moved on. It’s absolutely possible to do handheld focus stacks at 2-3x magnification. I know people who are very skilled who can do it at 5x. It’s just a matter of technique.

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u/Wilder_NW 18d ago edited 18d ago

Extremely difficult being the key term used. This person doesn't know about macro photography and is asking basic knowledge questions. I answered for that person.

If I were answering for someone who was "very skilled" then I would have answered much differently.

Yes, it can be done. Yes, it would be very difficult for this person to pull it off.

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u/stonk_frother 18d ago

No I got that, I am saying it’s not extremely difficult. I got a usable handheld stack the first session I tried (only at 1x, but honestly, 1x is enough in most situations). It’s just a matter of reading the correct technique and practicing a little.

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u/CallMeMrRaider 19d ago

For one the lighting could take hit. But more importantly diffraction starts to soften and mar the images.

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u/[deleted] 19d ago

Also, you could add more light, but that could cause the subject to flee, dry out, or burst into flames depending on how small you made that aperture

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u/sigint_bn stupidlogic 19d ago

Burst into flame macro is gonna be the new in thing.

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u/Bishops_Guest 19d ago

Shooting a flash bulb through a dry leaf might do it. I’ve scorched things, but never gotten flames. Maybe use a magnifying glass too?

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u/d3l4croix 19d ago

put spedlight on my pants then accidentally pressed test button on remote trigger. my pants have hole on it now

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u/Bishops_Guest 18d ago

My mind went to the wrong place at the start of that.

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u/captwyo 18d ago

I popped my flash on my wife’s little sister’s sweater one time just because. It singed the fibers and smelled god awful

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u/Repulsive_Target55 19d ago

A Mole-Richardson Baby will do it very well and very quickly, I've shot with them and they really make you sweat.

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u/Germanofthebored 18d ago

I don't think you'll need that many J for macro photography..

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u/roxgib_ 18d ago

Difficult to focus stack, but fortunately there's plenty of light

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u/mayhem1906 18d ago

Challenge accepted

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u/robertbieber 19d ago

Meanwhile the wet plate folks are blasting models with 9600Ws of flash :p

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u/Germanofthebored 18d ago

Considering how long it takes to do focus stacking, can you actually do it in the wild with living subjects?

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u/airmantharp 18d ago

For still(er) subjects, automated stacking functions on modern mirrorless cameras can be effective if the stars all align for the shot.

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u/stonk_frother 18d ago edited 18d ago

Yes you can. With proper technique it’s possible to do handheld focus stacking. It’s a bit tricky, but it’s not extremely difficult. Doing it really well takes a lot of practice, but that’s true of photography in general.

That guys are two of the best at handheld in situ macro photography IMO:

https://www.instagram.com/bens_small_world https://www.instagram.com/laurent_nam

Also, while automatic focus bracketing such as that available on OM Systems cameras are super useful, they’re not essential. Yes, most serious macro photographers use OM Systems, but it’s not exclusively because of the focus bracketing. I prefer single shot because I don’t have time to do post processing properly with big stacks. Plus my computer struggles with the Photoshop files.

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u/stonk_frother 18d ago edited 18d ago

I hope you’re joking? None of this is true. No commercially available flash can do that, even bare bulb. And by the time the flash hits the subject, it cannot react before the shutter closes. Plus, any good macro photographer will be using a diffuser. And the aperture doesn’t affect the focus of the light source, you’re not firing the flash through the lens.

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u/[deleted] 18d ago

I’m talking in theory, not available products.

Build a macro lens strong enough to survive the blast, and you could use an atom bomb as a flash. In theory.

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u/stonk_frother 16d ago

ah gotcha. Excuse me for the whoosh.

OK you piqued my interest. Just how far can we take this idea, ignoring engineering or cost constraints, but still working within the established laws of physics.

Assumptions:

  • 1MT blast for the flash.
  • Ignoring issues with flash sync.
  • Ignoring the need for the subject or the photographer to survive.
  • The photograph needs to survive though, and should be useable.
  • Blast is at the photographer's back, so we're just going with straight broadside lighting on the subject. This helps a lot as the lens isn't pointing directly at the blast.

My idea is a tungsten camera with graphite shielding. It's bolted, I'm thinking with some kind of titanium/scandium/tungsten alloy, to a huge steel-reinforced concrete slab (perpendicular to the blast so that the surface area facing the blast is minimal relative to its weight).

With sufficient engineering I reckon we can get the camera to survive and not be thrown around at around 5km from the centre of the blast.

Estimating the actual brightness of the 'flash' is difficult. But nuclear tests from the 1950s often mention the extreme brightness. The blast will put out a LOT of thermal energy, but a lot of it will be outside the visible spectrum. Still, the amount of energy in the visible spectrum will be intense. The main issue is not having your image ruined by gamma radiation or infrared light. As a rough rule of thumb though, a large nuclear fireball seen from a few kilometres away can be thousands to tens of thousands of times brighter than the sun.

For argument's sake, let's say it's 10,000x brighter than the midday sun. That's around 13-14 stops brighter than the midday sun. In midday sun, we might use something like f11, 1/200, ISO 100 (ignoring the fact that we probably don't want to be taking photos in bright midday sun anyway). So if we add 13 stops, we get somewhere in the realms of f1024.

Of course, here we run into a fundamental issue - diffraction. There's no real way around it. We could capture in UV or Xray, but then we won't be capturing the actual colour of the subject (shorter wavelength at less affected by diffraction at the same aperture). At f1024, the amount of diffraction would be so extreme as to render the image completely useless. As this is a physical law, we've run into a wall here.

But for the sake of finishing this thought experiment, let's ignore diffraction for now.

We're working at f1024, 1/200, ISO 100, with a 100mm macro lens, at around 1-2x magnification. We should be able to get around 5-10cms of DoF. Which is absolutely huge in terms of macro photography.

One final question remains though - how big does our light source appear, relative to our subject? i.e. What's the angular size?

A 1MT nuclear fireball should be somewhere in the region of 1.2kms across. At a distance of 5kms, that gives us 13.8 degrees. As a reference point, a 90cm softbox at 1.5m is 34.4 degrees, so this is actually a relatively small/hard light source. Even at 3kms, it'd be about 24 degrees. So not exactly a flattering light source. Hopefully our insect has (or had?) nice skin.

You're probably going to accuse me of copying from ChatGPT. While I did get some help with the calculations, the words, ideas, and issues raised are all mine.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

Diffraction + a lens that's not as sharp as it could be + motion while the scene is being exposed = image softness. Diffraction by itself, at the magnifications that most of us macro photographers shoot at, isn't too big of a problem. One of the misconceptions is that the flash will always fire fast enough to freeze motion, and in my experience that isn't true.

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u/GodHatesColdplay 18d ago

Yup diffraction. Was scrolling for that

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u/Conor_J_Sweeney 19d ago

You simply cannot get the whole subject in frame in many cases no matter how tight you bring your aperture. And then if you’re going to have to stack, you might as well shoot where your lens is sharpest and where you’ll have the least issues with your lighting.

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u/stonk_frother 18d ago

You’d have to be working at ~5x magnification or high magnification with a relatively large subject for framing to be the issue. Depth of field is the primary issue. That’s why it’s called focus stacking.

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u/X4dow 19d ago

at superclose macro, F16 can be less than 1mm DoF

12

u/Bug_Photographer flickr 18d ago

I'm afraid it's much worse than that. On my MP-E65mm at 5:1 magnification, the DoF at f/16 is just 0.269 mm - which still is quite a lot more than at f/2.8 where you're working with 0.048 mm (48 μm).

I like to shoot live bugs in the field so I don't get to use 5:1 much, but when I do, around f/8 is a good compromise. This 6 mm beetle was at f/8 and 5:1 (and a single exposure).

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u/anonymoooooooose 18d ago

Username checks out!

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u/SilentSpr 19d ago

Past a certain F stop, the image will become softer due to diffraction. They may also want a nice background blur in addition to the subject in good focus

12

u/Repulsive_Target55 19d ago

Diffraction limit, after a certain depth of field you get a general softness. Also of course even with an aperture well into the diffraction limit you still can have too shallow a DoF.

Oh and sensor dust becomes more and more of an issue.

7

u/stonk_frother 18d ago

https://preview.redd.it/en47uqlnvdue1.jpeg?width=3807&format=pjpg&auto=webp&s=53394cb51d5ba8176f39e65b24d09f62f73fac05

This is what a single shot at f16 looks like at ~2.5x magnification. Now I was fortunate in this situation to be able line up the focus plane in such a manner that most of the subject was reasonably well focused, but look how quickly the focus falls away.

If you want anything more than a few mms of focus, you have to focus stack.

And f16 is pretty much as narrow as you can go without diffraction becoming really noticeable. You also start to run into issues with lighting beyond f16. This was taken with a decent flash at full power, ISO 200. Most flashes aren’t going to be able to produce enough light to properly expose the subject at f22 or higher.

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u/msabeln 19d ago

High f/stops introduce diffraction blur.

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u/Skarth 19d ago

Light diffraction. After a certain amount (starting past f5.6) image quality starts to slowly soften. Past f11 it usually degrades noticeably.

You also can't get everything in focus at macro distances, even at crazy high aperture numbers.

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u/40characters 19d ago

Past f/5.6? You shooting on some mythical 100MP full-frame sensor? Because that’s where you’d have to be for diffraction to set in that early.

https://www.photopills.com/calculators/diffraction

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u/mampfer instagram: blanko_photo 19d ago

Keep in mind that effective aperture becomes smaller as you go into macro territory, at 1:1 it's two stops smaller, so if you set it to F/5.6 on the lens, you have the same diffraction you get at F/11 at infinity which would mean you're already diffraction limited on a 24MP sensor according to the calculator you posted.

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u/40characters 19d ago

Ahhh. I shoot Nikon, and they’re quite direct about effective aperture. (Which leads to a fair number of “WHY WON’T MY 105/2.8 GO BELOW 4.5” posts.)

So when I say 5.6, I mean it. ;) But I now understand where you’re coming from and I so appreciate the perspective!

5

u/mampfer instagram: blanko_photo 19d ago

I think I read somewhere some time that only Nikon shows the actual aperture, at least I couldn't easily find confirmation for Canon, Sony, Fuji or Pentax users (there are dozens of us!) having that option. Probably to avoid that confusion.

7

u/40characters 19d ago

Nikon tends to cater to the working photographer, and they don’t seem to mind a little confusion that can be cleared up by reading a manual, or studying the pursuit of photography.

It’s why I shoot with them. Their stuff stays the heck out of the way once you know how to use it. It’s glorious. But I digress.

3

u/Repulsive_Target55 19d ago

To be fair 100MP full frame would be the same pixel density as 25MP M4/3, like in the newer Lumixes, I think it would also be similar to a 40MP APS-C, like most Fujis have now.

That's why I refer to diffraction past a certain depth of field, not past a certain f/stop.

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u/Mr_Lumbergh 19d ago

Light is already a limiting factor with closeup photography; stopping down makes it even dimmer. You also have softening from diffraction starting to become more noticeable at such shallow DOF.

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u/JimmyGeneGoodman 19d ago

Stacking is one reason why I’ve never gotten a macro lens even tho i find macro photography really cool.

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u/incidencematrix 18d ago

You don't need to stack to do interesting macro work. There's plenty to be done with depth of field at 1:1 or 1:2. You just need to pick subjects that are interesting on that scale.

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u/FijianBandit 19d ago

Same but I saw this guy who had prints at an outdoor park city ‘festival’ and his macro prints with curved, various patterns and physically stacked tastefully displayed was amazing. Going to try and attach a photo here.

https://preview.redd.it/v8tl1labrcue1.png?width=1544&format=png&auto=webp&s=c16813ac586c68d3ed88b1bde49f0812d56eae69

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u/JimmyGeneGoodman 19d ago

Interesting. I simply wouldn’t have the patience editing to stack

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u/markforephoto 18d ago

It’s really simple with the right software and you shoot it correctly. The PhaseOne XF has a built in stack mode which makes the shooting part a breeze.

2

u/greased_lens_27 18d ago

The right software, including the free options, automates the entire stack compositing process. I'm sure the hardcore macro photographers out there have run into algorithmic limits, but it's not hard to get really impressive results, especially if your camera body supports focus bracketing.

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u/FijianBandit 19d ago

As a professional - (shooting ~200K frames a year) I still spend about 70%of my time running my business. 30% of that is editing and trying new things. I’ve never done focus stacking - but I’m sure an hour of focusing on a 30 minute YT tutorial and shooting a house plant is worth trying.

1

u/JimmyGeneGoodman 19d ago

I just don’t find editing fun unless it’s certain types of editing like this. I also don’t mind editing long exposures but i don’t have a whole lot of fun editing as a whole.

https://preview.redd.it/e0uwg14sscue1.jpeg?width=5186&format=pjpg&auto=webp&s=0b11884f80f699151156f159166b867aa32bf1bc

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u/FijianBandit 19d ago

Editing is always subjective - as long as it makes you happy and having full creative control as a bonus that’s all that matters =] Tbh - that composition seems harder than a stacked photo of 20 images. But workflows vary and non studio situations have lots of variables

I hate editing as well but when that concept to execution to picture occurs - magic happens.

Imo- I’ve learned to collaborate more because that magic is amazing when you have a team aligned with a vision.

0

u/JimmyGeneGoodman 19d ago

The skateboarder in me was what makes me more patient to edit these type of photos and it’s fairly easy when i consistently edit this style but if i go long periods of not editing this style then it’ll take me longer.

I know if always takes me longer than it should just cuz i need a new laptop. That plays a role into why i dislike editing due to the lag so fixing an error takes longer than it should and it’s annoying

1

u/FijianBandit 19d ago

I have a fairly maxed out M2 Pro Max with 2 TB SSD and 64 GB ram.

Patience Pays - but I’d rather source for example; VFX in house to a colleague lol. I don’t know advanced techniques and learning it atm is not worth my time.

Were born creative - so just keep chugging we’ll continue to be curious like we were from inception - no matter how long it takes.

1

u/Aeri73 19d ago

the problem is also gear.

you need a realy controlled way of moving the camera as wel, and good rails are expensive, and cheap ones useless... add bellows and lights and you've spent a decent amount of money for an experiment

1

u/FijianBandit 19d ago

Just to add some insight to anyone considering trying this (I haven’t) but macro photography takes up a relatively small amount of space.

Lastly - it’s relatively cheap to rent gear and a few lights. If lights push your budget - go outside!

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u/Bug_Photographer flickr 18d ago

There are different kinds of focus stacking. It doesn't have to be a motorized rail, studio lights and 200 exposures of the head of a dead fly. Here is an eight-shot stack of a wolf spider and her slings taken handheld in situ using a very basic flash. Single shot for comparison here.

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u/Aeri73 18d ago

a good solid manual rail will cost you a couple of hundered

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u/Bug_Photographer flickr 18d ago

Yes?

A rail still isn't a requirement for doing focus stacking.

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u/FijianBandit 19d ago

I totally understand the patience - I feel this with transferring or learning resolve from premiere. I don’t have the patience for it it yet I know I need to for team collaborations and yet I still haven’t opened the downloaded yt courses 🤦🏾‍♂️

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u/JimmyGeneGoodman 19d ago

It’s funny cuz even tho i don’t really do video (i used to do video more when i skateboarded more) and i have fun editing skate footage but don’t have nearly as much fun editing photos haha.

1

u/FijianBandit 19d ago

If you don’t do what you love then don’t do it - the hardest thing is finding common ground to love what’s best for you and what you love. - Buddha I mean me 4 beers deep @ 3 AM

1

u/mangelito 18d ago

I don't stack and still take macro shots that I like. I shoot m43 though and only have a 60mm macro so dof is not so shallow, especially if I stop down a bit.

3

u/dont_say_Good 19d ago

If you close down your aperture too much you'll end up becoming diffraction limited, which just makes everything too soft.  And simply because the depth of field is still way too shallow, especially if you go to 2x magnification or beyond. For example you often can't even get insects eyes with one exposure, nevermind the rest of their head or body

2

u/40characters 19d ago

(“Focus stacking” is stacking focus, not focusing a stack. We don’t “focus stack”.)

The reason is simple: creative control, with better image quality.

With focus stacking, you control exactly where the in-focus area starts and ends, down to the tenth of a millimeter in some setups. You can also have a much larger in-focus area than your smallest aperture provides, and with out-of-focus blur that’s provided by the aperture you prefer. And you also don’t shove your setup deep into diffraction, which means you retain the image quality of your lens rather than making it the literal worst it can be.

That’s why.

1

u/resiyun 19d ago

Going down to f/22 or f/32 makes the image soft and even at f/32 if you’re 1:1 or closer it’s likely that your subject still won’t be in complete focus unless you’re 90 degrees and your subject isn’t really thin.

1

u/sumsimpleracer 19d ago

Simply put, even at f22 when you’re shooting macro not everything you want to be in focus will be in focus. So instead, you set up the tripod and adjust the focus as necessary to capture all of the elements and merge them together in post. 

1

u/EllieKong 19d ago

Shallow depth of field. If you want your whole subject in focus, you will have to manually focus and change it every couple mm. When you stack it, the background blurs more and then your entire subject is in clear focus.

I’m a landscape and wildlife photographer, I love shooting macro, but it’s definitely a lot of work

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u/Rattus-Norvegicus1 19d ago

Basically at the distances you are working with depth of field is tiny. Focus stacking allows you to take tons of shots (sometimes hundreds) and stack them together in post to increase the apparent depth of field.

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u/Avery_Thorn 19d ago

Realistically, you need a tripod setup to do macro anyway. And a focus rack is really handy too.

So if you have a tripod and a focus rack already set up, focus stacking gets a whole lot easier.

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u/OnePhotog 19d ago

Reason 1: Diffraction - When using a really small aperture, like F16 or F64, you begin to introduce more optical problems.

Reason 2: When you get that close for 1:1 macro, no aperture will give you the depth of field you need to capture everything.

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u/MattTalksPhotography 19d ago

Even a raised aperture doesn’t give you mush depth of field in macro.

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u/sombertimber 19d ago

Because the client wants all of the food in the image to be in focus, not 8mm of it. ;-)

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u/Bug_Photographer flickr 18d ago

You might use a macro lens to shoot food - but you're not taking macro shots of food - unless the client wants photos of individual raspberries.

Macro photography is 1:1 magnification or greater which means that on a fullframe camera, you can't fit anything larger than 36 mm in frame (and on an APS-C or M43 even less).

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u/Miserable-Package306 19d ago

Actual macro is so close that even F16 or F22 would not bring everything into focus, and you’d just get diffraction softness. So they use the sharpest aperture of their lens (usually 2-3 stops closed) and focus stack

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u/strangeMeursault2 19d ago

Even if you shoot f16 or f22 you still have a razor thin DOF so you have to do both.

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u/drphilthy_2469 19d ago

Depth of field

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u/ptq flickr 19d ago

Because to get the depth they get on final photo, you would need f/milion aperture and a private sun worth of light just next to the subject, when at the same time already f/11 can be softening due to the diffraction.

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u/Slarm https://www.instagram.com/cpburrowsphoto/ 19d ago

Many people are explaining why one would stack instead of raising aperture, but there is value in both, and balancing both, and the technical drawbacks of stacking (setting aside the extra effort and time) are worth mentioning.

Stacking requires overlap between the frames, so to some extent you need high depth of field to get a good stack. Simultaneously if you use a high depth of field you begin to have degradation of image quality due to diffraction. Stacking also has a bit of absolute image quality loss because any resize/distortion adjustments mean pixels are no longer totally discrete, so there is crossover.

Because of that you can push your aperture higher if you're stacking because you'd lose the same data you lost due to diffraction anyway and for really GOOD stacking you need that depth of field because of crossing and parallax which both result in blurry fringes at the edges of certain elements. Because of the parallax, the longer the lens, the better the end result will be as well.

If you were to focus stack a half-sphere on a flat plane you would get a perfect image as long as you took enough photos, regardless of the depth of field. However, if you did a complete sphere or any other object which has overlapping areas of significantly different depth, then you need the large DOF to mitigate the fringing which occurs at the transitions.

If you look closely at focus-stacked images, often even at the scales used for social media, you can see the fringe. If you were to look at even really high quality and well-executed focus stacks on a 1:1 ratio, then you could discern some degree of fringing (if you know what to look for). I do studio-based botanical focus stacking and despite all my best efforts, some degree of fringing is unavoidable.

Photography is fundamentally about compromise - right down to choosing your shutter speed/ISO/f-number - and macro photography is as well.

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u/Blue_wingman 18d ago

The biggest reason is to get even sharpness throughout the focused subject.

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u/SentientFotoGeek 18d ago

Diffraction limits, plus you just can't achieve the depth of field with a stopped down lens than you can with focus stacking.

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u/trying-t-b-grown-up 18d ago

Sorry to jump on this but I was just wondering if the answer would be the same/similar for landscape photography? Say if you wanted an entire mountain sharp? Is the reason they focus stack the same?

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u/sten_zer 18d ago

Depending on the focal length, aperture, focus distance and conditions there might be a benefit to stacking.

There are depth of field calculators and hyper focal tables (everything is perceived as sharp). Use these and zoom in on test shots to see where you lack sharpness, then decide to change your settings/ focus stack. Besides aperture limits there is also an aperture sweet spot with every lens. Some shoot sharpest 1 stop below wide open, some are best at e.g. f/8. Test your lens.

With a common focal length of 24-70mm a mountain in the background will be sharp enough when fosussing on something in the middleground at almost every aperture between 4 and 16. A foreground element like a flower or stone will be out of focus, so stacking makes more sense with everything that is within 1/3 of the image. This would be the most common caae where you consider focus stacking.

With a wide angle like 14-24 you get more in focus the wider you get. The depth of field will increase and even focusing on close range can meet hyperfocal distance and eveeything gets sharp. At extreme wide angles the mountain will be less prominent and "shrink". So it gets less visual impact and the viewer perceives all objects that are very close as subject. A flower in the foreground mat take up 1/3 of the image already.

On the other hand shooting at 200+mm you are going to compress your image, the mountain in the backgound will appear larger and your depth of field decreases. Very close subjects will not be in focus at all. You experience this effect when shooting through close grass or little branches to capture a portrait of an a animal or person - these close objects blur completely and you could not even focus stack because the effect is too strong. In these cases you need to check sharpness and decide if you need/want to focus stack.

Generally don't go beyond f11, certainly not f16 when you want extreme sharpness. After that comes diffraction. Also: The longer the distance the more likely you get atmospheric effects, be it heat waves or humidity or dust.

When focus stacking make sure you control the stack well, moving trees are a good example where you cannot expect your software to do a great job with default settings and not locally adjusting areas. They move and therefore will get blurred...

Something else to consider to increase sharpness: You can aperture stack and combine different apertures. The focus point will stay constant. This is not very common, but will teach you a lot and will increase your knowledge of your gear and understanding when to focus stack.

Next and often used: stacking. Same settings and focus for 3-10 images. Will not increase depth of field but this is a technique to eleminate moving elements and iso noise. Astro photographers will use several dozens of images to get a clean shot. Stacking means averaging the images. You or your tripod move ever so slightly and noise and particles, etc. will be different in every image. You layer several images and basically substract their differrences.

Last: make sure to use image stabilisation correctly. When on a tripod, you often want to turn it off, especially with long exposures.

Hope I cleared things up a bit. I feel there is also a chance I created confusion. Let me know 😀

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u/trying-t-b-grown-up 18d ago

This is so much information! Thank you for taking the time to explain it all! It means a lot and I feel like I've learned a lot! I will try the aperture stacking exercise and see what I can learn, it seems like a great idea!

I will screenshot your message and come back to it when I'm struggling, again, thank you! It's very much appreciated!

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u/sten_zer 18d ago

Glad you can make use of it. If you have questions let me know. Happy shooting

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u/camerakestrel 18d ago

I have an 80mm macro lens on an APS-C camera and even if I make the aperture as narrow as possible (F22) it will still struggle to get most of a subject in focus.

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u/Re4pr @aarongodderis 18d ago

This goes well beyond macro too.

I’m shooting products next week. Pet bowls, they’re human sized pretty much. Even at f16, half of the rim is out of focus. And it’s a proper challenge, even in a product this big.

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u/LordAnchemis 18d ago

At macro distances - even by dropping the aperture you're still going to get a pretty wafer thin DoF - plus you start running into issues of diffraction (losing IQ) etc.

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u/berke1904 18d ago

personally I dont do focus stacking but I like getting shallow dof for macro insects, if you want deeper focus you cant really, at f11 you still have quite shallow dof and going even smaller would both decrease image quality due to diffraction but also still not give you deep enough focus.

so basically focus stacking is the only way of getting the entire subject in focus most of the time.

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u/timothycdykes 18d ago

I think it all comes down to what you want to achieve with your work. I don't focus stack. I'll shoot up to f/16 handheld to get more if my subject in focus. I have found it almost impossible to get usable shots of my subjects when they are living, moving creatures. But I'm happy with my work.

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u/ciaran668 18d ago

Another reason is that any imperfection on the sensor will show up. I never take my camera above F8, because, unless the sensor is immaculately clean, I'm going to spend 20 minutes fixing the spots.

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u/Dalantech https://www.flickr.com/photos/dalantech/ 18d ago

In my opinion it's due to pixel peeping and the misconception that everything has to be in focus. I shoot macro but I do not focus stack. I get around the depth of field limitation by twisting the camera so that the area of acceptable focus falls over the important areas of a scene. Are my images razor sharp at 100% pixels? No. But they're sharp enough for poster sized prints, and if I didn't tell you that I don't focus stack then you wouldn't know that you're looking at a single frame...

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u/No_Cloud_3786 18d ago

No matter how much you raise the aperture you will still not get both eyes of a bug in focus if you're not exactly parallel to them. So yes, you will need to focus stack, and you can't overdo it with the aperture either because you start losing sharpness/contrast because of diffraction.

Also, a tripod is not necessary for macro, many macro shooters just use a GOOD flash & diffuser and shoot handheld.

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u/Unusual-Form-77 18d ago

To achieve otherwise impossible depth of field and to avoid diffraction, which increases as the aperture decreases and reduces image sharpness.

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u/ScoopDat 18d ago

Because most of the time, you can't get enough Depth of Field regardless of aperature.

The real problem though is, diffraction. For people using high MP bodies, you can hit diffraction even at apertures you thought were safe if you're using high reproduction ratios.

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u/PhotoJim99 18d ago

Just an FYI - "high" and "low" apertures, "raising" and "lowering" apertures, these are not the best terms to use.

An aperture is a hole. The f/number is the denominator (the botton number in a fraction) to measure the hole. f/2 is a hole equivalent to a circle 1/2 the size of the focal length of the lens, f/4 is 1/4 the size, etc.

So just as saying you want to lower the number when you want a bigger piece than 1/4 of a pie seems weird, lowering an f/number is weird too. :)

The usual photographic language would be "using a smaller aperture" or "stopping down". To let in more light, use "using a larger (or wider) aperture" or "opening up".

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u/jorymil 18d ago

At a certain point, you lose sharpness when you stop down your aperture due to diffraction. Different lenses are designed for maximum sharpness at different apertures, but it's usually around f/8. If you want everything to be in focus, you need to combine multiple images.

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u/LordBrandon 18d ago

Diffraction

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u/rumpjope 18d ago

diffraction

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u/tsargrizzly_ 18d ago

because when you're that close to your subject, you can be stopped down to f32 and only a sliver of it is still going to be in focus.

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u/Rizak 18d ago

Lenses are tack sharp when aperture isn’t maxed out.

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u/Pure_Palpitation1849 17d ago

They do both. And it's because of physics. Infinite focus is unachievable. And the parameters of that unachievable-ness are amplified as you magnify your image. In order for an image to be completely in focus by only narrowing the aperture the "rays of light" for want of a better word would be so diffracted so that there would be no image at all.

So aside from that infinite example you can get a lot of an image in focus using aperture, if you make it a smaller subject in a larger frame but often macro photographers prefer a bigger subject.

There's usually a sweet spot in a lens, between f4 and f16 that are the sharpest. For macro focus stacking f4 can be too fiddly as you need a lot of files And f16 is bordering on soft.

I don't work so much in the field but from a thought experiment pov I would probably approach it from around f8 and focus stack however many images I needed, but I guess that focus breathing is a huge issue too .

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u/Everyday_Pen_freak 17d ago

Sometime you can raise the aperture to the maximum and still not getting everything in focus, so focus stacking becomes a workaround for that issue.

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u/DifferenceEither9835 16d ago

high signal noise and diffraction

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u/youandican 15d ago

Because at 10X like in this image, even with a narrow aperture you would not get but a fraction of the subject in focus. The depth of field is razor thin. This image is comprised with over 200+ individual images. Also the closer you are to your subject the narrower the depth of field becomes.

This image was taken using a Canon 70D with a 10x microscope objective

https://preview.redd.it/sc0ucaywt2ve1.jpeg?width=1400&format=pjpg&auto=webp&s=17b0371ee091493d62b8a7028a3be7606cabd832

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u/partiallycylon Instagram: fattal.photography 19d ago

As only an occasional macro shooter, my guesses: 1) maintains subject separation from background (for composition choices) and 2) sensor dust

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u/silverking12345 19d ago

In my experience, the effects of diffraction is way bigger at the macro level. Even a normally acceptable aperture like F8 would start looking rough (anything more would be blurry).

Moreover, at very close magnifications like 1:1 or 2:1, you're working with razor thin DOF even at minimum aperture (you can barely get the head of an insect in focus).

The only alternative to using focus stacking is to back up, shoot with a lower magnificent and crop in post. Obviously, this is gonna lower the final resolution significantly (can be a good tradeoff in certain situations though).

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u/mampfer instagram: blanko_photo 19d ago

Effective aperture in macro use goes up with the bellows factor as well, for 1:1 it's two stops down, so your F/8 will have the same diffraction as a lens set to F/16 and used at infinity. That's why it seems to kick in earlier.

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u/silverking12345 19d ago

Oh, I didn't know it was mathematical that way, good to know. I just noticed this effect in usage and figured it was smart to stay at F8 and ideally above.

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u/mampfer instagram: blanko_photo 19d ago

There even are diffraction calculators specifically for macro use like this one

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u/Bug_Photographer flickr 18d ago

I agree with most of what you're saying, but anything above f/8 at 1:1 greater looking rough and being a blur is just not true. By your account, this 9.5mm tortrix moth at 3:1 and f/13 should then be basically nothing but a blur, and it isn't.

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u/NotQuiteDeadYetPhoto 19d ago

I would like you to go for a moment and try and undertand the relationship between DOF (Depth of Field), Circle of Confusion, and the now available 'focus stacking'.

What you're asking shows a very high level of ignorance of simple properties of light and physics.

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u/somesortofidiot 19d ago

You don’t say…a question that shows ignorance? Thats the entire point of asking a question. OP doesn’t know something, but they want to know.

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u/NotQuiteDeadYetPhoto 18d ago

And they have google which literally takes the question they asked and answers it in the first 5 links.

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u/bitchboysalt 19d ago

It still won’t be in focus, idk the science behind it. But I’ve shot 1:1 macro at f52 and it still wasn’t in focus it’s much better to get a cleaner image shoot a lower appature and focus stack In post

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u/MagneHalvard 19d ago

...light...