Author Topic: Lyman-Alpha II Experimental f1.1/90mm mirror lens  (Read 12819 times)

John Geerts

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #30 on: November 19, 2018, 10:59:15 »
Yes, love it.

Is such a lens easy to 'reproduce' ?

Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #31 on: November 19, 2018, 12:45:18 »
Yes, love it.

Is such a lens easy to 'reproduce' ?

If you are willing to grind mirrors and have them coated, sure ;-)
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Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #32 on: November 19, 2018, 12:46:21 »
Btw. here is a video I took a while ago using this lens: https://youtu.be/9H2xTk7z7rI
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John Geerts

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #33 on: November 19, 2018, 13:07:07 »
 :)   Thanks for the link. Really looks 3 dimensional.


Termite

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #34 on: November 19, 2018, 15:17:02 »
Thanks for the video! I'd like to see you walk down a street with this lens, to see what it would do to houses and people.

Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #35 on: November 19, 2018, 18:09:19 »
Thanks for the video! I'd like to see you walk down a street with this lens, to see what it would do to houses and people.

Difficult, as DOF is razor thin, and I don't have a follow focus...
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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #36 on: November 20, 2018, 21:49:21 »
Quote
Difficult, as DOF is razor thin, and I don't have a follow focus...

Ah, I  meant what houses and people would look like if you shot them similar to the pictures above.  I wasn't expecting perfect follow focus   ;)

Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #37 on: November 21, 2018, 08:36:06 »
Ah, I  meant what houses and people would look like if you shot them similar to the pictures above.  I wasn't expecting perfect follow focus   ;)

Have a look, here is some in there: https://www.flickr.com/photos/kds315/albums/72157702692038345
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Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #38 on: November 22, 2018, 00:08:55 »


Amber tree (aka American Sweetgum) in late autumn
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Robert Camfield

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #39 on: November 24, 2018, 00:39:09 »
Klaus,

Very, very interesting...I don't have a sense of the optics, and why the out-of-focus areas are rendered circular, rather swirl-like.

Thanks much...Robert

Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #40 on: November 28, 2018, 00:36:46 »
Klaus,

Very, very interesting...I don't have a sense of the optics, and why the out-of-focus areas are rendered circular, rather swirl-like.

Thanks much...Robert

It is this special mirror lens construction which causes a bent field, as there are no field flatteners, as in other mirror lenses.
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Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #41 on: November 28, 2018, 16:10:08 »


Its does UV, too. A rather "unfriendly" comparision of its f1.1 to the UV Nikkor 105mm at f4.5 (left) [UV-Nikkor 105mm with Baader-U front filter, Lyman Alpha II with rear UG11+S8612 filter stack]
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Robert Camfield

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #42 on: November 30, 2018, 03:42:39 »
Klaus,

Thanks for clarifying the point regarding the bent field...The comparison with the Nikkor - an orchid perhaps - provides further evidence of the capabilities of the UV 105.

Tks, Robert   

Dr Klaus Schmitt

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #43 on: December 04, 2018, 16:02:22 »
Klaus,

Thanks for clarifying the point regarding the bent field...The comparison with the Nikkor - an orchid perhaps - provides further evidence of the capabilities of the UV 105.

Tks, Robert

Indeed it does, yet those mirror lenses also have their merits, as there is no focus shift over a very wide field, deep-UV to far-IR for instance and there are quite longer focal lengths available, too. And not to forget their high speed (low f-stop) like this f1.1 lens (effective about f1.4 due to the central obstruction)
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Frank Fremerey

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Re: Lyman-Alpha II Experimental f1.1/90mm mirror lens
« Reply #44 on: December 04, 2018, 19:26:46 »


Its does UV, too. A rather "unfriendly" comparision of its f1.1 to the UV Nikkor 105mm at f4.5 (left) [UV-Nikkor 105mm with Baader-U front filter, Lyman Alpha II with rear UG11+S8612 filter stack]

I do understand right: there is no aperture mechanism to create a comparable DOF? can it be built into a shutter with aperture mech like a Copal?
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