> 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?

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robotmay 3 hours ago | parent [-]

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.

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dofm 3 hours ago | parent [-]

> 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.

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robotmay 3 hours ago | parent [-]

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.

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dofm 3 hours ago | parent [-]

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.

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robotmay 2 hours ago | parent [-]

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

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dofm 2 hours ago | parent [-]

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)

	▲	robotmay 2 hours ago \| parent [-]
		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