> 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?
Why? Where can I read/learn more about this?
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.
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.
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.
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.
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.
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.
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
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)
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
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.