External star aperture lens

[torashi]

Hi y'all!

I once saw somewhere fotos and info about a wide angle lens with an external star-like aperture that was slid on to the exterior element. I was recently trying to find some info on it again, but it seems that I'me completely unable to find any info on it. Maybe some of you can help me out with a manufacturer and lens name.
Thank you very much.

HFG

[Steven Tribe]

Perhaps you mean the Goerz Hypergon series X?

This (or rather some versions of it) had a rotating device in front of the lens which evened out falling edge illumination. This is before graduated ND filters were introduced.

[torashi]

Yes, I think it is the right one. I was mistaken. It's not an aperture, but rather a curious way of dealing with falloff.

[Dan Fromm]

Perhaps you mean the Goerz Hypergon series X?

This (or rather some versions of it) had a rotating device in front of the lens which evened out falling edge illumination. This is before graduated ND filters were introduced.

Steven, you're right, the Hypergon was introduced in 1900. Graduated ND center filters weren't far behind. Rodenstock sold one as early as 1912. See www.pacificrimcamera.com/rl/00718/00718.pdf

[Jim Jones]

External star-shaped apertures have been used to form star-shaped out-of-focus point light sources in images.

[Jac@stafford.net]

I'm sorry this picture is not as clear as it could be.
The rectangle in the center is a reflection, not part of the filter.

Anyway, the star pattern is a center-filter. It mitigates darkening by the edges. (Format is 8x10. Lens is wide angle.) Camera is in 'service position'. In use it points straight-up.



(Another angle - link here)

[torashi]

Wow! Is that an anti-aerial camera? That's a cool contrast and center filter all in one.

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[torashi]

External star-shaped apertures have been used to form star-shaped out-of-focus point light sources in images.

Yes, I've used masks on shallow dof lenses to get cheesy figure bokeh

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[Jac@stafford.net]

Wow! Is that an anti-aerial camera? That's a cool contrast and center filter all in one.

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I cannot tell if you are talking to me. The filter is just one of a set of clear, yellow and red. I might still have another.

Not anti-aerial. I think it was one of a cluster to observe aerial launches. I've given away the factory notes.

A most interesting part was the high-speed shutter. I added a b/t manual control. The rest was electric - not shown.

[torashi]

I cannot tell if you are talking to me. The filter is just one of a set of clear, yellow and red. I might still have another.

Not anti-aerial. I think it was one of a cluster to observe aerial launches. I've given away the factory notes.

A most interesting part was the high-speed shutter. I added a b/t manual control. The rest was electric - not shown.

Yes, I was replying to your comment and photo. Sorry for not quoting.

I didn't know the name, so since it was ment to be pointed upwards (unlike an aerial camera, and clearly very different in characteristics and design) as you mentioned, I just used the word "anti" to badly imply opposite, not anti-aircraft batteries.

Now that you mentioned a cluster of cameras, it must have been expensive as hell to produce cf's for them all. This would have been more cost effective.
This makes me wonder how the grooves affect diffraction and contrast vs. a metal vapor deposition cf.

I have to say, this is becoming a really interesting thread about unusual center filters. I wonder what other designs there are out there. Maybe even some lost to history.

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