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