This is a fixed issue in cameras. Stop down to F16, and use a ring flash, there you go, fixed.
This is basic math. It's interesting that someone else claimed it's "physics" as a retort, when yes indeed it IS physics. It's why you can make a tiny lens fixed focus camera that seems to have everything in focus, from near to far, because the DoF becomes enormous.
You have a 4mm lens at f/2. To get the same depth of field you'd need a 50mm lens at f/25, not f/512.
You don't need to use a 50mm lens though. Macro lenses are typically 24mm or so. So you need to shoot at F12 to have the same depth of field in reality, certainly not f/512...
And my camera actually moves the sensor AND the lens instead of just the lens. Because of that it can stabilize in the near field MUCH more efficiently than an iPhone ever could.
Humorously years back I had authored a giant depth of field essay with online calculators specifically because so many people just couldn't understand why their iPhone couldn't get bokeh. Yes, f/512 would be the impossible equivalent. This is easily calculated.
Regardless, the lens Apple uses for macro mode has a 1.54mm focal length. The 4mm example was just demonstrating how fundamentally small cameras win on depth of field, at least if you want maximal depth of field. Conversely they lose when you want to limit depth of field, which is why we have computational bokeh.
"Macro lenses are typically 24mm or so."
The smallest from most makers is 35mm, but the majority are 50mm+.
This conversation has turned weird. As someone who has had many SLRs, and many lenses, and has taken thousands of macro photos, I know that in the real world macro photography is a massive pain. That DoF is by far the number one obstacle (which is why focus stacking is simply necessary, often with ten or more varied focuses). Physics benefits small camera systems for that specific scenario.
Also yes, the wide angle of the iPhone 13 is much smaller. Just stop down even further then.
Cheap macro lenses in 2021 are typically around 24mm. I'm talking about the Mitakons and the Laowas of the world.
Focus stacking is needed when you're trying to take very high detail pictures with 60, 70, 90mm lenses on high resolution sensors. You don't need anywhere near as much to take an image with the same magnification as a 13mm equiv. 2cm away.
Go to the wikipedia page on depth of field and see how it is calculated.
"Cheap macro lenses in 2021 are typically around 24mm"
You claimed they were the norm. Now it's that they simply exist.
"Focus stacking is needed"
Focus stacking is needed when the depth of field is so small that the resulting photo would be unpleasant. This is the case for almost all macro photographs shot on SLRs. It's interesting that someone else claimed this is a fixed issue and posted a photo that looks like it was taken with one of those terrible lens adapter kits. If that is one's standard for "fixed", then sure, but most of us have higher standards.
However, for a smaller format, we arguably ought to reduce the CoC proportionally. And I think that reduction will end up canceling out one factor of f, bringing us back to the ratio of the focal length to the f stop (i.e. the absolute diameter of the aperture).
The iPhone is widely assumed to have a CoC of 0.004mm (this actually increases on the most recent iPhone, though it's tough to get precise numbers). A Nikon D5000 (going with an equivalent resolution -- larger pixels -- on an ASP-C camera) has a CoC of 0.020.
So let's calculate hyperfocal distance of the two systems for the same effective focal length (but obviously very different real focal lengths)-
iPhone 12 telephoto lens - 65mm (7.5mm real) equivalent, f2.2.
Nikon D5000 equivalent lens - 65mm (43mm real) equivalent, f2.2.
For the iPhone, the HF is 6.4m. For the Nikon, it is 54.3m. For those who don't know, hyperfocus is the point where everything from 1/2 of that distance to infinity is in focus if you set the focus to that magical point. It's a proxy for the other depth of field calculations, and is the simplest to demonstrate.
Anyone who owns an iPhone w a "telephoto" and an ASP-C SLR w/ a 50mm lens needs to try to replicate bokeh at various distances without the computational bokeh. Focus on a subject at 1m, 2m, 4m, etc at the same aperture. Close down the aperture on the SLR even.
I think it makes sense to assume the same target resolution for the iPhone and the DSLR, even though this isn’t true in practice. The DSLR user is obviously free to downsample their photo to a lower resolution and thereby (in a rather uninteresting way) gain more depth of field. We shouldn’t be giving the iPhone extra DoF points just because it happens to have a lower resolution.
So we are not talking about any empirically derived value for the iPhone’s CoC. The CoC here is a value derived for each format from an arbitrarily chosen target resolution.
It yields a practically perfect comparison of focus. This isn't a trick or handicapping, and the degree of focus/defocus is identical whether that SLR had 10x the resolution. There is utterly nothing arbitrary chosen here, and the amount a tree 10 feet outside the focus is out of focus will be identical on a 12MP SLR or a 24, 48, or 96MP version with the same focal length / f / sensor size.
By resolution here I’m talking about what we could crudely measure in megapixels. Say for example that we have a target resolution of 5MP. We then calculate the corresponding CoC for both cameras based on their respective sensor sizes. You’ll find that the CoC for the iPhone will be smaller in proportion to the difference in focal lengths between the iPhone and DSLR. That cancels out one of the factors of f.
Sudosysgen is saying the same thing, but without going indirectly via the DoF formula that you’ve been using.
I calculated the hyperfocal length for an iPhone and an equivalent zoom SLR, at the same aperture. These yield effectively identical degrees of focus from 1/2 the HF to infinity. The iPhone is from 3.2ft to infinity, the SLR is from 27 feet to infinity.
Nothing else matters if you can't tell me why that's wrong. Because it isn't wrong. It's absolutely right. The same zoom level and cropping. MASSIVELY larger focus zone.
If we doubled both dimensions of the sensor, thus doubling the CoC, it would halve the HF. If we instead doubled the focal length it QUADRUPLES the HF. The focal length is a squared factor and outweighs any other component. For a reason.
That's your issue - you need to use equivalent apertures.
Set sensor size to "custom (NaNx)". Set Custom Sensor to "1". Set focal length to "25mm". Set aperture to "f/2". Set distance to 2m You will find a DoF of 759mm.
Then set Custom Sensor to "0.5". Set focal length to "50mm". Set aperture to "f/4". You will find a DoF of 748mm due to rounding errors in the calculator.
Then if you set custom sensor to 2, focal length to 12.5, and aperture to f/1, you'll find a DoF of 739, again not quite equal due to rounding errors.
As you see, if you double the sensor size, double the focal length, and use an equivalent aperture, you have the same DoF.
Your mistake is one that’s easy to make and one that I’ve made myself before. We’re not trolling you. You’re just losing track of a factor of f and thereby getting the wrong result.
By the way, I also agree with your overall point about smaller sensor cameras being better suited to macro photography. It’s just that your f512 claim is based on a mistaken calculation.
There is no mistake. Your first paragraph is unfortunately founded on some misunderstandings of optics, however I calculated the hyperfocal length for an equivalent ASP-C 35mm system and an iPhone at the same crop (which anyone with an SLR and an iPhone can replicate in moments). The iPhone has a dramatically higher DoF. There are no mistakes in that calculation. This is the reason why you need computational bokeh. It's why it's so easy for everything to always be in focus. Could someone contrive ridiculous focal length / f-ratio / CoC parameters? Of course they can -- it's just a function with parameters that you punch in, and they can offset. In actual reality, however, short focal length is the primary input into why small cameras feature larger depths of field. Why we talk about the equivalent aperture in the way that we talk about equivalent focal length.
sudosysgen's argument in the end seems to distill down to "yes, but compare it via the equivalent DoF f-stop on the larger camera" which is a short circuit of the entire argument. It is basically saying that AMC is worth the same as Apple if AMC shares were each worth $4636.
Okay.
Therefore, when you use the same CoC, you are asking the DSLR to be dozens of times closer to perfect focus, in pixel terms, than the iPhone, which is why you are calculating outlandish f stop values.
If instead, you have a target that the object must resolve to a pixel with the same resolution on both, you will arrive to an f stop linearly proportional to the sensor size, instead of proportional to the square of the sensor size.
At this point I feel like you are just posting things hoping some future visitor will think that your commitment must demonstrate that you are right. I guess.
If your goal for macro photography is to take a picture that is reasonably sharp at 12MP 2cm away with a magnification of less than 2, then yes, getting acceptable depth of field is a solved problem. Set your wide angle macro lens to F/22 and there you go.
If you have higher standards, then the problem is not fixed on DSLRs. But the iPhone doesn't do it either.
If you don't understand why using the CoC criteria for depth of field is incorrect on two cameras with vastly different sensor sizes, I can't help you. The only measure for depth of field that works across cameras with two different sensor sizes is the ratio of distance and aperture diameter, which determines the solid angle of light capture. You're the one that brought up physics, so actually look at the physics instead of using photographer's ready-made formulas without actually understanding them and where they break down.
As for the image that you replied to, it doesn't look any worse at all to the images in the post technically. If you look at the image of the lightning connector, it doesn't even have 2mm of depth of field at a pretty low actual resolution. You can say whatever you want as for the composition and artistic value, that's not what we're talking about.
No, you can't, because you are painfully ignorant on this topic.
Literally, spend 30 minutes with an iPhone and an SLR and you'd be illuminated. Instead you seriously argue that I need to look at the "physics" (which is farcical when you ignore the most important part of a camera, which is the focusing from the lens to the sensor. Dismissing that betrays a complete misunderstanding of optics).
This conversation is clearly futile, but again - spend 30 minutes and actually test your theories. Or, you know, read any single article on the tubes.
Or how about simply ask yourself "why does the iPhone need to do computational bokeh"? 65mm equivalent lens, f/2.2...should be the easiest thing in the world. In SLR world that is bokeh gold.
That is literally the one and only thing that matters. The diameter of the lens, and the distance from the object. Take a piece of paper, draw the lens as a slit, draw the object as a point, and make a line from the two edges of the slit to the point, that continues furhter back. You'll get two triangles. Everything that is contained in those two triangles will be focused to the same point on the sensor. That's why the ratio between the two is what matters. That's why closer objects produce a more out of focus background than objects farther appart. That's what I'm trying to explain to you.
The DoF formula that photographers use does not work for comparisons across two different film sizes.
Further my 70mm lens has a smaller aperture than my 35mm f1.4 lens. Yet it has a much smaller depth of field for a given distance. Weird! Lens makers must not know your remarkable "slit lens" trick.
At this point I'm convinced you are either trolling, or have dug so far into the depths of wrongness that you're dedicated to sticking with it. So good luck with that. I'm out of this conversation.
The ratio between distance and focal length only works if the focal lengths are equivalent across the two cameras. Otherwise it doesn't work. That's to say, a 70mm f/2.8 has the same depth of field as a 35mm 1.4 lens if the second is on a camera with 2x crop factor.
Try it out, crop the image of your 70mm lens at f/2.8 and compare it to the image of your 35mm f/1.4 lens and you will get exactly the same image with the same blur (assuming the lenses are exactly 70mm and 35mm at the focus setting, which is not guaranteed due to focus breathing and manufacturers rounding off their focal lengths)
Your 35mm f/1.4 lens has a physical aperture of 35mm/1.4 = 25mm, so the equivalent 70mm lens with a 25mm aperture would have an F-stop of f/2.8. Hmm, can't think of many modern 70mm lenses besides Sigma's 70mm/2.8 macro which should have the same DoF, or if it's a standard zoom they should have equivalent DoF as well (unless it's Canon's f/2 zoom).
The (acceptable) depth-of-field is derived from blur-disk diameter, and the circle-of-confusion, for an object at a certain distance from subject ("point of focus") and relies only on physical aperture and distance to subject as stated (or alternatively, f-stop _and_ focal-length, because "phys. aperture = focal-length / f-stop").
Bokeh is the quality of rendering of out-of-focus highlights.
It's a fixed issue.
I don't think that is the demonstration you think it is. Most macro photographers would not rack that up as a successful photo.
And again, focus stacking is what everyone does to compensate for the DoF weakness.
You don't, which is why higher depth of field is the golden standard. See: The entirety of this discussion.
"so confidently to take such a superior tone"
To be clear, you dismissed my post by claiming that it's a "fixed" issue, then posting proof that doesn't show it to fixed. I don't believe I'm the one who attempted a superior tone.
Depth of field is *THE* issue in macro photography. Small focal length cameras are at an advantage in that regard. It's pretty simple.
It's exactly the same reason why 50mm f/2 lens produces the same image on a full frame camera as a 75mm f/2.8 lens on an APS-C 1.5x camera. It's just that instead of multiplying by 1.5 you're multiplying by 8.4.
Indeed an iPhone 13's ultrawide will provide exactly the same image and bokeh as a 13mm f/15.1 lens on FF
However, at 90mm the object would also be farther away, so you wouldn't need to stop down a lot more than you'd expect.