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  • Welcome to the new site. Here's a thread about the update where you can post your feedback, ask questions or spot those nasty bugs!

Do you love bubbly bokeh?

Asher Kelman

OPF Owner/Editor-in-Chief
Anything that helps rank important versus unimportant in a subtle manner is valuable.

This lens does a great job of bringing in the boat to appear sharply from a blur.

I love it too!

Thanks so much for sharing!

What happens when the lens stops down or this is fixed?

Asher
 

Dr Klaus Schmitt

Well-known member
Anything that helps rank important versus unimportant in a subtle manner is valuable.

This lens does a great job of bringing in the boat to appear sharply from a blur.

I love it too!

Thanks so much for sharing!

What happens when the lens stops down or this is fixed?

Asher
Thank you Asher!

There are VERY few specialized mirror lenses which an aperture, and this one also does not have that,
but a built in ND-filter wheel. No change to the bubbles though.
 

Jerome Marot

Well-known member
shot using a scarce scientific f1.1/90mm mirror lens
Can we have some info about the lens design? f/1.1 is very unusual for a mirror lens. The reason is that mirror lenses usually need a secondary mirror and a large aperture implies a large secondary mirror, which creates a large obstruction. Indeed the bokeh bubbles on your picture hint at a large obstruction as the "bubble" is very thin, but I find the whole idea puzzling.

It is possible to dispense with the secondary mirror by putting the camera at its place and that gives quite fast mirror lenses indeed (e.g. Celestron hyperstar, etc...). Is this what you used? That would be consistent with the horrendous coma aberration at the edge of the picture.
 

Dr Klaus Schmitt

Well-known member
Can we have some info about the lens design? f/1.1 is very unusual for a mirror lens. The reason is that mirror lenses usually need a secondary mirror and a large aperture implies a large secondary mirror, which creates a large obstruction. Indeed the bokeh bubbles on your picture hint at a large obstruction as the "bubble" is very thin, but I find the whole idea puzzling.

It is possible to dispense with the secondary mirror by putting the camera at its place and that gives quite fast mirror lenses indeed (e.g. Celestron hyperstar, etc...). Is this what you used? That would be consistent with the horrendous coma aberration at the edge of the picture.
The design is a very simple one and it is two mirrors ONLY! It was intended as a deep UV lens, to record images where glass and even fluorite / quartz lenses will not work anymore.

The is the sister lens, a 2.8/200mm one, as I don't have a picture of teh other one handy:

Nye 200mm image2_(c).jpg
 

Tom dinning

Registrant*
The lens looks really cool, Doc. Sort of thing I’d use to impress an astrophysicist.
As for the bokeh , Im less than ambivalent. Just a personal choice but is seems to be tizzing up a lousy photo. Or even good one.
Like a dag wearing a suit. Or a beautiful woman wearing too much makeup.
 

Dr Klaus Schmitt

Well-known member
The lens looks really cool, Doc. Sort of thing I’d use to impress an astrophysicist.
As for the bokeh , Im less than ambivalent. Just a personal choice but is seems to be tizzing up a lousy photo. Or even good one.
Like a dag wearing a suit. Or a beautiful woman wearing too much makeup.
Well, I got it (actually them) as they reach down to 190nm and I do a lot of UV photography, so the bokeh was a kinda neat side effect ony ;-)

And it does things no others lens does from what I have seen yet; slightly defocused to get that "tunnel whirl effect":



and focused:
 

Dr Klaus Schmitt

Well-known member
It is just two mirrors, but which ones? It is not as simple as it looks. What are the dimensions of the lens, in particular the diameter of the main mirror and the distance between the two mirrors?
Packed away, sorry....

The main mirror is approx. 100-120mm diameter from what I remember. The secondary approx. 50mm also from memory.
 
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