Manual Focus Lenses Forum

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

hello to all users. sorry for my english (translated by google)
I have this lens, which has a diamond-shaped aperture with two blades. anyone knows about news and any quotation? thanks to all for the answers that you give.

Pancolart · Expire: 2013-11-18

Interesting aperture indeed. Judging by the serial number it is a Sankor made lens.

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

do you know any quotation?

Langstrum · Joined: 16 Feb 2014 Posts: 351

I think it's about 30 Euro http://www.sitiodocanoamarelo.com/objetiva-carenar-50mm-f2-8-m42.html

But seems like this lens is supposed to have 6 blades, not 2 like yours. It looks like Helios 44M1. Maybe someone combined the diaphragm of Helios 44M1 and the rest of Carenar

Oh, I found it on Italia ebay, so you're selling it there?

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

Lloydy · Expire: 2022-01-01

I like that, you've got some great pictures from it - without overdoing the bokeh.

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

yes, thank you. I would like some information about lenses with this type of diamond blades, if they exist ........

Langstrum · Joined: 16 Feb 2014 Posts: 351

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

the diaphragm is formed by two blades that any opening in the shape of a diamond, diamond ....... from f 4 to f: 16 ...... I do not think it has been changed ..... ..
is just like that from the factory.

Attila · Expire: 2025-11-18

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

Attila ..... so there are already built factory?

Lightshow · Joined: 04 Nov 2011 Posts: 3666 Location: Calgary

I have an enlarger lens with 4 blades that has a square aperture, my Fujian 35/1.8 had a few blades that were shaped differently so that as you stop down the aperture becomes a rectangle, I opened it up and tried to round it out some.
So it is very possible to get non-standard aperture shapes.

vintageoptic · Joined: 24 Feb 2013 Posts: 14 Location: Italy

thanks ..... then tell me that this type of blades does not come from the factory?

Gamera · Joined: 16 Feb 2014 Posts: 86 Location: Scandinavia

I can not figure out how only two blades could function properly. Maybe there is more, like four?

I have a lens which is kinda related to this. I'll describe it here as info of diamond shaped diaphragms is requested.

C-mount Schneider-Kreuznach Xenoplan 25mm/1:1.9. This is the older silver version from 60's.
This one has two sets of blades, 4+4. These are in two planes, the set closer to camera body also closes in 45 degrees to the foremost one. The set closer to camera also is a bit more open all the time when opening and stopping down the diaphragm. When one looks through the lens from the front element, one sees only the almost diamond shaped diaphragm (the blades are very slightly curved). The other set seems to have some effect only when the diaphragm is stopped down. The other set likely cuts some of the light passing through the now effectively square opening of the foremost set of 4 blades. As the other set is in 45 degrees the combination makes a more rounded effect.

If this hijacks this thread, please open another thread and copy this post there.

G.

AlexKV · Joined: 12 Jan 2017 Posts: 14 Location: Serbia

Maybe a little late to post to this thread, just came here by google searching this lens.
I have the same lens with a little smaller serial number.
Disassembled the lens, and it is a factory made two bladed aperture, no mods. And it's pretty interesting how they made the aperture mechanics inside, quite different from other lenses.

Lightshow · Joined: 04 Nov 2011 Posts: 3666 Location: Calgary

Yup, factory design, just like the Rollei lenses with a 3 blade iris, an odd duck.
Post some pictures of all the parts please.
Thanks

AlexKV · Joined: 12 Jan 2017 Posts: 14 Location: Serbia

Here it is. The part which contains lenses is much smaller than the outer casing of the lens, so there is a lot of space inside when assembled, so it feels light in hands.
Japanese engineers made it from very few parts with nice machining inside.
There seem to be 3 lenses, or the center glass is actually two cemented lenses, not sure.
Also, all lenses have multicoating, which is nice.
And at last, you can see pretty interesting aperture blades.

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devinw · Joined: 19 Aug 2016 Posts: 207 Location: Portland, OR

Very interesting effect, and good usage of it to the OP ! Like 1 small

Mechanically, that's about as dead simple as you can make an aperture (short of a fixed hole Very Happy

)

AlexKV · Joined: 12 Jan 2017 Posts: 14 Location: Serbia

Yeah, couldn't be less complicated than this. This is the least complicated lens design I've disassembled so far.

alex ph · Joined: 16 Mar 2013 Posts: 1802

I once disassembled a faulty point-and-shoot plastic Ricoh camera. As already Cosina 35 and many later automatic exposure compact cameras, it had a similar joined aperture/shutter construction, with the same diamond-shape diaphragm in a relatively large lens barrel. I wonder was not that Carenar an attempt to test in SLR engeneering a solution found earlier for point-and-shoot cameras?

AlexKV · Joined: 12 Jan 2017 Posts: 14 Location: Serbia

Maybe they just went for "as cheap as possible" solution, as the machining of whole lens looks cheap, but still precise. Even lenses are pressed and embedded into the rings, so less parts are used.