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Comment by dofm | Hacker News Reader

That is from the normal (24mm) camera slightly stopped down (f/1.8), judging by the EXIF.

Odd bokeh was one of the risks of adding a mechanical aperture, and bokeh is very often weirdest at the first or second down from open.

I would hope that the telephoto lens does not show this so severely (because it has a fixed round aperture) but all mobile phone lenses in my experience have had a tendency towards a sort of concentric-ringed, quasi-soap-bubble bokeh; it's a common part of the challenge of really tiny optics (that you either like or dislike). (The iPhone X was really distinctive in this regard). So it's not too surprising to see the aperture do this on top of that.

As a general rule you don't see it in average images, but I guess sensors are now high-enough resolution that it's becoming more obvious, and the blades of a mechanical aperture might make it quite noticeable in some situations.

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Polygonal aperture openings are not the cause of soap-bubble bokeh, it's the cause of polygonal stopped-down bokeh.

Heavily ringed bokeh just comes from the optics.

> Polygonal aperture openings are not the cause of soap-bubble bokeh

Errr, quite obviously not, indeed. But then I didn't say they were?

I said all phone lenses tend to have soap bubble bokeh as a consequence of their optics. Almost all phone lenses don't have mechanical apertures; they have fixed ring apertures and also tiny aspheric lenses.

(In the industry it's seemingly called "onion ring bokeh" to distinguish from soap bubble, presumably because it has more than one ring.)

However! The first stop down of a mechanical iris has a tendency to have odd effects on the lens's bokeh.

You get an interference of the aperture blades and the wide-open bokeh. With a lens that is prone to ring bokeh, slightly stopping down will smear the edge of the bubble, but in this case it is also clearly boosting contrast as you expect (and an irregular shape at different angles)

> But then I didn't say they were?

Is that a question?

I fucking love how the fact that English is totally, totally, literally non prescriptive breaks engineering type people’s brains.

Perfectly fine use of colloquial commenting?

Yes.

Against the ‘rule’ you were taught in primary school English? Also yes.

That’s why English is so interesting.

Thanks for asking, NuclearPM. It was not actually a question. In informal English a question mark can follow a plain statement, where then it indicates a non-specific uncertainty. In the case above, the sentence could be interpreted generally as: “I didn’t say they were... and I'm not sure what gave impression I did" or "I didn't say they were... I think you misinterpreted."

Does that make sense?

English be like this man. It's everything all-in-one. Fascinating language I tells you. Much like all other languages which be fascinating.

I would argue against the siblings and say, yes, it's a question; it's a shortening and softening of the rhetorical "But then I didn't say they were, did I?"

> Odd bokeh was one of the risks of adding a mechanical aperture, and bokeh is very often weirdest at the first or second down from open.

Why? Where can I read/learn more about this?

This is usually due to the blade shape and quantity I believe. The aperture is most likely to be less circular on the widest apertures after fully open unless you have quite a lot of aperture blades, as the curve to make a rounder aperture is usually applied more towards the tip of the blade, and you're only seeing the base of the blades at wider apertures. That varies a lot by aperture design, however - if you have the more banana-shaped blades where the retaining pin and pivot pin are at opposite ends (like in a Yashica TLR) then I believe they can maintain a more consistent curve along the length. Those also suck massively to reassemble, but that's a different story.

I haven't seen a diagram of how the aperture in this new iPhone is designed yet. There's a lot of different ways to do it, with lots of odd shape possibilities.

> This is usually due to the blade shape and quantity I believe.

Also because of things like angle of incidence?

The purely round lens will generally have nice round (or at least cats-eye) bokeh across the frame with an edge that degrades softly as a result of aberration, so beams of light from different angles tend to blur into each other.

As soon as you get aperture blades, you lose that soft edge, get contrast but also a lot of competing shape influences at different angles. They will tend towards more rounded shapes as you stop down more.

And that is putting aside that some aperture shapes are just really insane when they are nearly wide open, right? (Konica 40mm f/1.8 AR I am looking at you with your shuriken bokeh)

> I haven't seen a diagram of how the aperture in this new iPhone is designed yet. There's a lot of different ways to do it, with lots of odd shape possibilities.

Not a diagram but one closeup photo:

https://petapixel.com/2026/09/19/apple-explains-why-the-ipho...

and an animation:

https://petapixel.com/2026/09/09/iphone-18-pro-has-apples-fa...

Six blades with a slightly rounded hook in them by the look of it. Very noticeable sun stars at f/1.8, nice looking results at f/2.8.

Absolutely insane mechanical challenge and assembly challenge.

Ooh yeah I love those weird shapes nearly wide open. I found a lens that had a torx bit shaped aperture the other day, I'll have to fish that out and see what it looks like in an image. Lots of compact cameras have a diamond/square-ish hole, notably the Minox 35 range from what I can recall.

Edit: just saw your update with the photos of the mechanism. Wow that's impressive miniaturisation. The hexagonal shape looks surprisingly good. I wonder what's causing the odd effects in the OP. I have noticed in the past that iPhone cameras produce square specular highlights through tree foliage, so I wonder if it's an extension of that oddity.

Yes that mechanism only has two blades! They are sort of sickle-shaped. (Presumably gave the Soviet cloners a chuckle)

I found myself looking at it when I was considering making a DIY aperture for my DIY lenses. (I've personally settled on swappable Waterhouse stops for now but I might fit an eBay microscope aperture, many of them have loads of blades).

Oh and now I'm going to end up looking on eBay for a Minox 35ML or 35GT again. Seriously, never do this while logged in; Minox 35 sellers may be among the most desperate I've ever seen in terms of sending you offers, it's relentless.

Haha there's certain camera models that are very prone to that. Some of the Pentacon M42 lenses are worth a look if you want an unholy amount of blades - I have a 135mm f/2.8 sat around that has like 15 blades or something daft.

Coincidentally I think I have a non-working 35GT in my market stall (https://camerasetc.wales), so if you want a project drop me an email as I'll send it to you for the cost of postage. I have too much in my repair backlog and those things are fiddly little bastards at the best of times :D

Oh I think I have seen your website before!

I too have too much clutter so I will have to turn down your kind offer but I will peruse your sites and I may ping you a note sometime about a particular lens I have been looking for — quite a random cheap old one I regret parting company with. (I'm in Kent but I have a friend in Cardiff and if my wallet does not protest I may pop in on your stall)

Ooh do drop me any odd things you're looking for - I never know what's going to turn up, and I do keep a lookout for anything people ask me about. I have debated trying some sort of online stock listing but I think that might just end in chaos due to the lack of space I have for organised storage and other people moving my stuff around.

That reminds me that I need to do a new update post, whoops. I've had an absolute buttload of Pentax K mount gear the past couple of months, which is quite annoying as I don't have that many customers that shoot it. I'll have to big up the Pentax cameras a bit more haha.

Do swing by if you're ever in town when the market's open! I've always got lots of fun cheap stuff kicking about, and a bin of broken shit if you need parts :D

> Minox 35 sellers may be among the most desperate I've ever seen in terms of sending you offers, it's relentless.

Because they are a nightmare to own. So lovely when they work but so frustrating because you keep readjusting the shutter mechanism with those tiny screws and you end up wasting so many rolls (and pictures) in the process.

I own a 35GT, barely use it but wouldn't sell it because I have too much empathy. It would feel like receiving money to spell a malediction on someone.

It's not due to the aperture blades. It's due to the amount of spherical aberration in the lenses.

Professional camera lenses carefully control this. It's actually one of the only intentional "flaws" added to lens. Technically bokeh with a slight ring on it (on point lights) usually results in a tack sharp lens. You can see this in most macro lenses.

Portrait lenses are sort of the opposite - they want super smooth bokeh (point light sources in the blurred out of focus area will have a nice gradient that is soft and gradually drops off toward the edges). This results in a lens that has slightly less sharpness on the in focus portion. It's not that noticeable though on a great lens.

Most lenses are a balance. When shooting professional cinema many lenses are intentional chosen for their bokeh qualities. "Nervous" bokeh is more on the side of rings and is often found on older Russian and East German glass.

There are two lenses where the amount of spherical aberration is not baked into the lens. They were made by Nikon called "Defocus Control". The 105mm 2.0 DC and slightly older 135mm 2.0 DC both have a second ring that looks another aperture ring but allows adjustability of the spherical aberration from "nervous" to "smooth". They were marketed poorly and misunderstood but are some of the best glass you can get - they test insanely well and have huge flexibility.

> The 105mm 2.0 DC and slightly older 135mm 2.0 DC [...]

I almost never change the defocus control on the 135/2.0 from neutral, yet I believe the lens makes it almost impossible to take a bad portrait. The only reason to keep a DSLR around instead of a mirrorless is that this lens has an old-school camera driven auto-focus, which Nikon's F-to-Z adapters don't support. While manually focusing that lens can be done, the shallow depth of field makes it very challenging for moving subjects.

It's definitely worth messing with. The reason it has a F and R side (with aperture markings) is that a lens will be optimised to either provide ideal bokeh at close or long focus (long focus bokeh being things blurred in the foreground closer to the camera). Try setting it for example to F 2.8 real aperture and then I believe move the DC ring to R 2.8 or 4 and you should get a very pleasant creamy blur. Or for a slightly sharper portrait move to neutral or R 2.0

Soap bubble bokeh comes from overcorrected SA. Onion rings and related brightness anomalies/unevenness in bokeh are mostly the result of molded aspheric lenses. Stopping slightly down has not significantly impacted bokeh (apart from apodized lenses) since rounded aperture blades have been invented about fifty years ago.

The iPhone 18 aperture does not have rounded blades (except the tip). Six hooked blades, very truncated hexagon aperture (perhaps exactly a regular dodecagon, it’s a little difficult to tell from the promo images)

An aside re: telephoto lens: Duo doesn't have one! It creates the effect of a 2x lens by enlarging the unmagnified image.

Following on for clarity, this is why the Duo lacks a dynamic aperture. Seems they must have been quite squeezed for space.l indeed.

Even on the 18 Pro Max the 8x zoom of the telephoto lens is just the 4x using the same 12 MP crop of the 48 MP sensor to "double" the 4x optical zoom as the last generation. I hope we can get some level of optical zoom on a future Duo.

The 18 Pro does this too for 1x -> 2x. Same as the iPhone Air, as well.

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