Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

How does a fisheye lens work?

0 views
Skip to first unread message

mike

unread,
Mar 19, 2010, 5:20:16 AM3/19/10
to
How does a fisheye lens work?

Assume I can stand a LOT of image distortion.
Why does a fisheye lens have so darn many elements?

But the KEY question is this...

If I want a telephoto lens, I can get there with
a transmissive lens or a reflector.

Is there a reflective analog for a very wide angle (fisheye) lens?
How would one construct one?

Thanks, mike

dadiOH

unread,
Mar 19, 2010, 9:16:04 AM3/19/10
to
mike wrote:
> How does a fisheye lens work?
>
> Assume I can stand a LOT of image distortion.
> Why does a fisheye lens have so darn many elements?
>
> But the KEY question is this...
>
> If I want a telephoto lens, I can get there with
> a transmissive lens or a reflector.
>
> Is there a reflective analog for a very wide angle (fisheye) lens?

Yeah. Auto parts stores sell them...the small, round, wide angle mirror
thing to stick on your regular mirror.
______________

> How would one construct one?

1. Get a plastic mirror

2. Heat it

3. Bend it around part of a sphere. The more of the sphere you use, the
wider the view will be.


--

dadiOH
____________________________

dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

Message has been deleted

Paul Furman

unread,
Mar 19, 2010, 2:47:53 PM3/19/10
to

The difficulty with fisheye is the distance from back of lens to sensor
for DSLRs with a mirror box. That's why so many elements. You could use
a relay lens system but lose quality & speed, plus the image would be
upside down, or a front screw on type, which is the same idea sort of
but right side up. You can hang the camera above a silver ball and get
everything but the part of the sky that the camera blocks. I saw one
like that using an old 1970's L'Eggs panty hose 'egg' container,
apparently the guy found some advantage to the parabolic shape. Google it.


--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Savageduck

unread,
Mar 19, 2010, 2:59:19 PM3/19/10
to

There are such things as security mirrors.
http://www.domesandmirrors.com/mirrordome.htm
http://www.superiormirror.com/


--
Regards,

Savageduck

0 new messages