The April 2020 Challenge - day 17

MoonMind

Hall of Famer
Dec 29, 2013
Switzerland
Matt
A seventeen-bladed aperture, what lens is that? :)
Again, it's nothing more than a mathematical joke because I simply couldn't think about anything sensible to say about day 17. It's Gauss's hand-constructed heptadecacon (only ruler and compass) - which he considered his greatest achievement; today, it's considered maths trivia ... Funny that a letters guy like me can only think of maths in this context ... well, it's a number.

However, the question is valid. I don't know when they would last have used something as sophisticated as that - I only own some older lenses with 9- and 10-bladed apertures, but I've definitely read about higher counts ... Though in even earlier times, the apertures were inserted as boards with circular holes, it seems. In fact, my Agfa Isola II (a super-simple and cheap 6x6 tube camera - a proto-Holga) still works that way: f/11 is just a mask with a hole in it that's flipped into the light path:

A7202454.jpg


(Just a quick and dirty attempt to show it, you can just about begin to see the aperture; *not* today's entry by any stretch ...)

I'll have to let it rest here, but maybe someone else can chime in :)

M.
 
Last edited:

theoldsmithy

Hall of Famer
Jan 7, 2013
Cheshire, England
Martin Connolly
However, the question is valid. I don't know when they would last have used something as sophisticated as that - I only own some older lenses with 9- and 10-bladed apertures, but I've definitely read about higher counts ...
I'll have to let it rest here, but maybe someone else can chime in :)

M.
The 7artisans 25mm f1.8 has 12 blades.
 

MiguelATF

Hall of Famer
Aug 27, 2013
Talent, Oregon (far from the madding crowd)
Miguel Tejada-Flores
Again, it's nothing more than a mathematical joke because I simply couldn't think about anything sensible to say about day 17. It's Gauss's hand-constructed heptadecacon (only ruler and compass) - which he considered his greatest achievement; today, it's considered maths trivia ... Funny that a letters guy like me can only think of maths in this context ... well, it's a number.

However, the question is valid. I don't know when they would last have used something as sophisticated as that - I only own some older lenses with 9- and 10-bladed apertures, but I've definitely read about higher counts ... Though in even earlier times, the apertures were inserted as boards with circular holes, it seems. In fact, my Agfa Isola II (a super-simple and cheap 6x6 tube camera - a proto-Holga) still works that way: f/11 is just a mask with a hole in it that's flipped into the light path:

View attachment 219294

(Just a quick and dirty attempt to show it, you can just about begin to see the aperture; *not* today's entry by any stretch ...)

I'll have to let it rest here, but maybe someone else can chime in :)

M.
Well, for a "quick and dirty attempt" to show us your Agfa Isola - and even though this is not your entry for today - it's a fine photograph. The tones, the textures, the light....I think it's a great image.
 

MiguelATF

Hall of Famer
Aug 27, 2013
Talent, Oregon (far from the madding crowd)
Miguel Tejada-Flores
Day 17: post-midnight nocturnal view of my street

The old house (built in 1902) where I live is on the rural outskirts of what used to be a small Oregon farming town - and even before the silence of the corona virus quarantine, it's always been a quiet place - even more so, at night. But on clear-ish spring nights, I sometimes step outside and just stare up at the stars which, in spite of the ambient light from the nearby town, are usually quite visible. I was doing exactly that, tonight, when it struck me --- why not attempt a photograph.

But it's a very windy night, and though I put the Pen F on a tripod, everything was blowing around tonight - although, looking at the results, it almost seems like the stars are what are being blown about.

 

jyc860923

Veteran
Aug 29, 2018
Shenyang, China
贾一川
Day 17: post-midnight nocturnal view of my street

The old house (built in 1902) where I live is on the rural outskirts of what used to be a small Oregon farming town - and even before the silence of the corona virus quarantine, it's always been a quiet place - even more so, at night. But on clear-ish spring nights, I sometimes step outside and just stare up at the stars which, in spite of the ambient light from the nearby town, are usually quite visible. I was doing exactly that, tonight, when it struck me --- why not attempt a photograph.

But it's a very windy night, and though I put the Pen F on a tripod, everything was blowing around tonight - although, looking at the results, it almost seems like the stars are what are being blown about.

View attachment 219301
Really cool, looks like it's getting invaded by UFOs.
 
Again, it's nothing more than a mathematical joke because I simply couldn't think about anything sensible to say about day 17. It's Gauss's hand-constructed heptatecacon (only ruler and compass) - which he considered his greatest achievement; today, it's considered maths trivia ... Funny that a letters guy like me can only think of maths in this context ... well, it's a number.

However, the question is valid. I don't know when they would last have used something as sophisticated as that - I only own some older lenses with 9- and 10-bladed apertures, but I've definitely read about higher counts ... Though in even earlier times, the apertures were inserted as boards with circular holes, it seems. In fact, my Agfa Isola II (a super-simple and cheap 6x6 tube camera - a proto-Holga) still works that way: f/11 is just a mask with a hole in it that's flipped into the light path:

View attachment 219294

(Just a quick and dirty attempt to show it, you can just about begin to see the aperture; *not* today's entry by any stretch ...)

I'll have to let it rest here, but maybe someone else can chime in :)

M.
:sorry: for being off-topic. So I went through my collection of older bellows and enlarger lenses and alas, I didn't find a lens with 17 aperture blades. Got lenses with 15, 16, 18 blades and my highest count is for the Schneider Xenar 4.5/135mm with 19 blades.





Image gallery
 

MoonMind

Hall of Famer
Dec 29, 2013
Switzerland
Matt

Latest threads

Top Bottom